Final Report Summary - HELATHIS (High Efficient Very Large Area Thin Film Silicon Photovoltaic Modules) Executive summary:Photovoltaic (PV) solar energy generation already is the third renewable energy source after hydropower and wind power in Europe. The thin film silicon PV module is one technology which could achieve a wide market application due to easy production at large area and low cost and low environmental impact of production. To improve thin film silicon PV modules, optical confinement was identified as a major source of efficiency improvement by the 5 partners of the HELATHIS project. T-Solar Global S.A. (TS), silicon thin film PV module producer using Applied Materials SUNFAB technology, AGC Glass Europe (AGC), flat glass producer and three research institutions, the Forschungszentrum Jülich (FZJ), the Utrecht University (UU) and the University of Barcelona (UB) had formulated the Work Program of the HELATHIS project including the following 5 Work Packages (WP) to promote R&D of very large area (5.7 sqm) thin film silicon PV modules. The Work Packages (WPs) (apart from the WP1 for the Project Management) were organized by research dedicated to the -Front Surface- (WP2), the -Glass/TCO (Transparent Conductive Oxide) Interface- (WP3), the -Intermediate Reflector- for tandem cells (WP4), the -Back Reflector- (WP5) and -Advanced Characterization Methods- (WP6). The objective of the project was to push the implementation of optical layers as part of adapted thin film silicon solar cells into large scale production facilities, including most of the optical confinement strategies that are state-of-the-art in highest efficiency silicon thin film laboratory cells. In the time frame of 3 years a stabilized large scale 2.6 m x 2.2 m (5.7 sqm) module efficiency of 8% for single junction amorphous silicon (a-Si:H) and 11% for a-Si:H/microcrystalline silicon (mc-Si:H) tandem modules were scheduled. These module efficiencies together with cost reductions in the raw materials, as e.g. the TCO glass substrate supplied by AGC, was expected to lower the module production cost clearly under the 1 EUROS/W level at the end of the project.In the frame of the HELATHIS project AGC has improved its TCO glass from initially standard TCO glass AN10 to ANS10ME TCO glass, latter providing about 2% higher optical transmission. The solar cell fabrication process was optimized by TS for the ANS10ME substrate, resulting in an increase of stabilized efficiency of 5.7 sqm a-Si:H modules in production average from about 6.7% (382W) at the beginning of the project to about 7.3% (420 W) at the end of the project and achieving in the best R&D module an efficiency of 7.95% (455W). Production cost was about 0.7 EUROS/W in middle of 2012 and was estimated to reach 0.6 EUROS/W in 2013 including latest R&D steps and new implemented automation. During the operation of the project, the whole module production of Applied Materials SUNFABs in Europe (initially 5 factories with a nominal TCO glass volume of approx. 3 Mio. sqm/year) had changed from formerly in Japan produced NSG/Pilkington TCO glass to TCO glass produced by AGC in Moustier, Belgium, which presents a big impact on the European economy.For further improvement of the TCO glass, TiO[sub(2)] layers were identified at AGC and UB as suitable candidates to produce graded index layers between the SnO[sub(2)] TCO layer and the amorphous p-layer of the solar cell to reduce optical losses at this interface. However, within the project a suitable layer for the implementation in modules could not be successfully developed for the TS production process. Nevertheless, the interesting result obtained on small scale samples suggest, that this research should be pursued further. Furthermore, the application of a sol-gel anti-reflection coating (ARC) on the front surface of the TCO glass was investigated by AGC and UB and it was shown that the transmission of the ARC covered TCO glass could be increased by about 2%. The ARCs developed at UB and AGC were subjected to standard durability test conditions as e.g. in IEC 61646 norm and were found to be very stable. However, the implementation of a production process for sol-gel ARC resulted to be not cost effective at the actual low level of module price and efficiency.Intermediate reflector (IR) technology was investigated and developed in 1 sqcm tandem solar cells and laboratory modules up to a size of 30 cm x 30 cm. For this purpose properties of microcrystalline silicon oxide (mc-SiOx:H) layers deposited by PECVD were studied and optimized. A 30 cm x 30 cm tandem module with mc-SiOx:H IR with a record initial efficiency of 12.2% was fabricated by FZJ very close to the 12.5% efficiency aimed at the beginning of the project. The deposition technology of n-type mc-SiOx:H IR layers was implemented in the TS production process. With top cell and the mc-SiOx:H IR layer deposited in TS and bottom cell prepared in FZJ, a maximum initial efficiency of 11.9% has been achieved in 1 sqcm tandem cells. With the top cell and ZnO:Al IR layer prepared at TS and the bottom cell prepared at FZJ a maximum initial efficiency of 11.6% has been achieved in 1 sqcm tandem cells and 10.1 % for a 10 cm x 10 cm mini module for which, FZJ has developed an innovative laser scribe design for conductive ZnO:Al. Tandem module development could not be extended to 5.7 sqm module since TS could not make the expensive upgrade of the PECVD deposition system which was required in order to deposit device-quality intrinsic mc-Si:H, as a consequence of the photovoltaic market development with extremely low module prices and the global financial situation.ZnO:Al layers for the back reflector (BR) sputtered from rotatable targets were successfully optimized and implemented by FZJ on 30 cm x 30 cm scale. In a-Si:H/mc-Si:H tandem solar cells prepared with this BR, an initial efficiency of 11.3% was achieved. Ga-doped ZnO layers (ZnO:Ga) were implemented and optimized by UB. However, these two approaches finally were not considered for an implementation in TS production for cost reasons. The key issue in improving the BR performance is the use of an Ag layer instead of Al as BR which could improve the efficiency by about 5%. The increase of the Ag price and the decrease of overall module production cost in last years were shown to present a strong negative impact on the cost effectiveness of the implementation of the Ag layer and therefore the implementation was not considered by TS.To support the TCO glass and solar cell development, the surface morphology of industrial and laboratory TCOs was determined by SEM, AFM, XRD spectroscopy, optical transmission spectroscopy and angular resolved spectroscopy. Electrical properties were determined by Hall-effect measurements. Electrical and optical properties were determined of a-Si:H, mc-Si:H and mc-SiOx:H layers. The local transmitted light intensity distribution on TCO glass and TCO glass covered with a-Si:H p-i-n structure was obtained experimentally by near-field scanning optical microscopy (NSOM) and theoretically by rigorous solution of Maxwell's equations using the finite-difference time-domain method. A CCD camera inspection system was developed and successfully implemented in the TS production line for the detection of infrared radiation emitted from the module when stimulated by a forward current and so indicating defective areas, providing an excellent assessment of the electrical quality of each module at the end of the production process.Project Context and Objectives:Project contextThe European Union's new energy and environment policy, agreed by the European Council in March 2007, establishes a forward-looking political agenda to achieve the Community's core energy objectives of sustainability, competitiveness and security of energy supply. To make this a reality, the European Union (EU) is committed to the "20-20-20" initiative [Communication from the Commission, COM (2008) 781 final, Brussels 13.11.2008 p. 2.]. To adapt the research activities to the recent difficult economic situation in Europe triggered by the financial crisis starting in 2008, the EU has created the new Framework Program for Research and Innovation - Horizon 2020 [http://ec.europa.eu/research/horizon2020/index_en.cfm'pg=h2020]. It is expected that around 35% of the Horizon 2020 budget (approx. 80.000 Mio. EUROS) will be climate related expenditure e.g. in renewable energies [Communication from the Commission, Horizon 2020 - The Framework Programme for Research and Innovation, COM (2011) 808 final, Brussels, 30.11.2011 p. 5.]. Photovoltaic solar energy generation (PV) will play a relevant role in the future renewable energy production presenting with 58% annual growth rate from end 2006 to 2011, the highest growth rate of all renewable energy sources worldwide [Renewables 2012 Global Status Report, (Paris: REN21 Secretariat, Renewable Energy Policy Network for the 21st Century) p.13.]. With about 52 GW of PV installed in 2011 in Europe, PV [Global Market Outlook for Photovoltaics until 2016, p. 12 (EPIA, http://www.epia.org)] already is the third renewable energy source after hydropower (260GW) [International Hydropower Association Activity Report 2011 (IHA, London) p. 13.] and wind power (98 GW) [Renewables 2012 Global Status Report, (Paris: REN21 Secretariat, Renewable Energy Policy Network for the 21st Century) p.57.] in Europe.When creating the HELATHIS consortium (see http://www.tsolar.com/helathis online), the 5 partners had jointly identified optical confinement as a major source of efficiency improvement for thin film silicon PV modules. To promote this development, a work program had been formulated based on the expertise of 2 companies with high volume production and the know-how of 3 widely recognized public research organizations.- T-Solar Global S.A. (TS) is a company producing very large area a-Si:H modules having increased its production capacity within the project from nominal 40 to about 70 MWp/year. The 5.7 sqm PV modules fabricated by TS with "SUNFAB" technology from Applied Materials are the largest modules in the world market.- AGC Glass Europe (AGC) is the European branch of the worldwide biggest producer of flat glass with long time experience in fabrication of transparent conductive oxides (TCO) on glass, the substrate for silicon thin film modules.- The involved research centre Forschungszentrum Jülich, (FZJ, Institute of Energy and Climate Research 5, IEK-5, Germany), the University of Barcelona (UB, Dept. of Applied Physics and Optics) and the Utrecht University (UU, Debye Institute for Nanomaterials Science, located now in High Tech Campus Eindhoven) are performing research in silicon thin film technology since several decades and provide detailed knowledge on laboratory scale high efficiency thin film silicon solar cell technology, on deposition technology of thin film silicon and TCO layers and micro and nanotechnology.ObjectivesThe objective of the project was to push the implementation of optical layers as part of adapted thin film silicon solar cells into large scale production facilities, including most of the optical confinement strategies that are state-of-the-art in highest efficiency silicon laboratory cells. In the time frame of 3 years a stabilized large scale 5.7 sqm module efficiency of 8% for very large area single junction amorphous silicon (a-Si:H) and 11% for very large area a-Si:H/ microcrystalline (mc-Si:H) tandem modules were scheduled. These module efficiencies together with cost reductions in the raw materials, as e.g. the Transparent Conductive Oxide (TCO) glass substrate supplied by AGC, was expected to lower the module production cost clearly under the 1 EUROS/W level at the end of the project. To achieve these objectives a Work Program containing 5 Work Packages (WP) dedicated to research and development activities was organized apart from the WP1 Management- for the project coordination.The present project identifies optical light confinement as a key point to increase efficiency in silicon thin film modules. The optimization of the properties of TCO layers deposited on front glass as front contact of the solar cell and the back reflector have to be achieved for large area deposition. Additionally, methods for the reduction of reflection losses at the front glass are developed. This optimization has to be done, on the one hand, for modules with a-Si:H single junction (SJ) and, on the other hand, for modules with a-Si:H/mc-Si:H tandem junction (TJ), where, in the latter case, also an intermediate reflector for light management between top and bottom cell is considered.The project developed innovative schemes for application in very large area industrial modules. This finally included most of the optical confinement strategies that are presently state-of-the-art in highest efficiency thin film silicon laboratory cells. The objective of the project was the implementation of optical layers as part of adapted thin film silicon solar cells into large scale production facilities. In the time frame of 3 years a stabilized large scale module (5.7 sqm) efficiency of 8% for very large area single junction and 11% for very large area tandem modules was scheduled. Furthermore, in 30 cm x 30 cm a-Si:H/mc-Si:H tandem mini modules an initial (stabilized) efficiency of 12.5% (11.5%) and in a-Si:H/mc-Si:H tandem solar cells of 1 sqcm of 13.5% (13%) and was projected. The module of the TS production consists of a glass/Poly Vinyl Butyral (PVB)/glass laminate in which the front glass is the TCO covered glass substrate (in the following TCO glass) where TS deposits the solar cells structure. The TCO glass is fabricated in a float glass line by AGC on very large area (about 6 x 3 sqm) and then cut to the 5.7 sqm size. The back glass of the module has a hole where the electrical contact is provided by a junction box glued on the back glass. On the back glass also metal profiles are glued to fix the module on the ground structure. The a-Si:H/mc-Si:H tandem structure was also under investigation in the frame of this project. a-Si:H/mc-Si:H TJ solar cells and modules have been intensively studied on laboratory level at the laboratories of the FZJ, UU and TS with the objective to optimize tandem structures with intermediate reflectors (IR) and high efficient tandem cells and mini modules were fabricated with ZnO layers and newly developed microcrystalline silicon oxide (mc-SiOx:H) IR layers. The main objectives will be presented in the following by Work Packages (WP).WP2 Glass front surface4% of the light reaching the surface of a solar module is reflected at the air/glass interface. Any reduction of this reflection represents a significant and assured increase of solar module output. This reflectance reduction can be achieved by antireflective coatings (ARC) that have a refractive index that e.g. decrease with their thickness from the index of glass (n=1.5) towards the index of air (n=1).This index variation is obtained e.g. by controlling the porosity of the coating throughout its thickness. Principle objectives of WP2 were:- Development of anti-reflective coatings (ARC) on front glass surface.- Implementation of ARC on large area solar modulesWP3 Glass / TCO interfaceTo get a baseline of the performance of different TCO glasses in single junction a-Si:H solar cells, at the beginning of the project benchmark tests have been performed with a variety of TCO glasses available within the consortium. Next, the objective for AGC was to further develop its TCO glass to reduce the gap between off-line and in-line industrial TCO glass and to perform the respective test-runs in the production line of TS. Objective was to produce a prototype very large area (5.7 sqm) module with 8% stabilized efficiency and a prototype large area (5.7 sqm) a-Si:H/mc-Si:H tandem junction module with stabilized efficiency of 11%. Moreover, an objective was to develop new concepts to improve the TCO functions at a laboratory scale. Furthermore, AGC and UB have investigated the application of a thin refractive index (n) matching TCO layer with intermediate refractive indices between the standard tin oxide TCO layer (n=2) and the amorphous silicon layer (n=3) to reduce the reflection losses at the TCO/a-Si:H interface.The principal objectives in WP3 were:- Benchmarking of commercial and laboratory TCO substrates with newly developed TCOs.- Development and improvement of new front TCOs by in-line and off-line APCVD.- Characterization of newly developed TCOs.- Application of newly developed TCOs on very large area.WP4 Intermediate reflector (tandem structure)The incorporation of intermediate reflecting layers has a great potential for the optimization of tandem solar cells with a-Si:H top cell and mc-Si:H bottom cell. Intermediate reflectors (IR) are used to provide selective light distribution for light management inside thin film silicon solar cells. The objectives for thin film silicon solar cell development are the improvement of the total energy conversion efficiency by increasing the absorption in the top cell and the reduction of the top cell thickness without losses in the total efficiency. The latter will reduce the material consumption and production costs, in addition to the improvement of the stabilized efficiency. Further objective was the development of 1D photonic layers or the so-called distributed Bragg reflector (e.g. ZnO/Si/ZnO .Si/ZnO) as IRL.The main objectives in WP4 were:- Decreasing the thickness of the top cell by the use of a spectrally selective intermediate reflector between the sub cells and maintaining the current of the tandem cell.- Successful development of a robust IR that can be implemented in industrial production.- Development of novel multilayer IR that has photonic properties.WP5 Back reflectorThe state-of-the-art back reflector deposition of the TS production line is done by dc sputtering of ZnO:Al followed by an Al metal layer. The back reflector along with the front TCO layer plays a crucial role in p-i-n type thin film silicon solar cells by increasing the optical path of light inside the device resulting in short circuit current gain. The objective was to evaluate at the beginning of the project the performance of the current back reflectors (BR) of the laboratories (UU, UB, FZJ), who in particular apply an Ag-layer in the BR, to give an accelerated feed-back for the possible efficiency gain which could be achieved in large area modules using an alternative BR structure. In order to investigate new materials and techniques for producing efficient BRs, objective was to develop back reflectors with Ga-doped ZnO (ZnO:Ga) by UB and the deposition of ZnO:Al layers by sputtering from rotatable targets by FZJ.The objectives in WP5 were:- Accelerated feedback from laboratories to improve the efficiency of industrial modules- Development of back reflectors on the laboratory scale with potential for up-scaling to large area modules- Evaluation and application of the optimized back reflector to industrial large area modulesWP6 Advanced characterization methodsIt is the aim of the project to increase the efficiency of thin film solar cells by improving the light trapping efficiency and by reducing parasitic losses. The improvement in the light trapping is achieved e.g. by antireflection coatings at the front glass surface, the optimization of the surface morphology of the front TCO layer, the implementation of intermediate reflectors (in the case of tandem solar cells) and the improvement of the back reflector. Standard methods for the characterization of solar cells are the measurement of current voltage curves and external quantum efficiency however, more advanced methods were developed and applied to determine the properties of materials and layers and to characterize the light trapping properties of TCO layers and ARCs.The main objectives in WP6 were:- Analysis of the surface structure and identification of optimised profiles for light trapping- Application of advanced electrical and optical characterization methods- Identification of the best stabilized ARC under light-soaking and environmental conditions- Development and implementation of an IR camera inspection system in TS for module quality assessment.Project Results:Work Package 2: Glass front surface4% of the light reaching the surface of a solar module is reflected at the air/glass interface. Any reduction of this reflection represents a significant and assured increase of solar module output. This reflectance reduction can be achieved by antireflective coatings (ARC) that have a refractive index that e.g. decrease with their thickness from the index of glass (n=1.5) towards the index of air (n=1). This index variation is obtained e.g. by controlling the porosity of the coating throughout its thickness. In Work Package (WP) 2 antireflection coatings based on sol-gel processing were developed to reduce the reflection of light at the front side of the TCO glass used as the substrate for thin film silicon solar modules.Task 2.1 Industrial very large area SiOx ARC by sol-gel (AGC) and Task 2.3 Test of ARC on large area moduleIn this task AGC developed a process to cover the front glass on large area with a thin SiOx-containing layer based on a sol-gel process which e.g. is used also for cover glass of crystalline silicon modules. The new challenge here was that the glass was already covered with the TCO-layer at the back side and an optimization of the whole sol-gel process had to be performed. The objective of the task was to demonstrate in the frame of the project a transmission increase of 2% in the wavelength range interesting for a-Si:H single junction (300-800 nm) and a-Si:H/mc-Si:H tandem junctions (300-1100 nm) on an area of 1 m x 0.5 m. Latter was the maximum size on which AGC actually could perform the ARC process on industrial level in a pilot line. Deposition of ARCs on the front surface (tin side) of a TCO coated glass sheet has been performed at the AGC R&D centre's pilot line in Lodelinsart, Belgium. The average reflectance in a wavelength range from 400 to 1000 nm is 7.4% (varying from 7.2 to 7.6%). On the TCO glass before AR-coating the reflectance was measured as 9.2% (average 400-1000 nm). This means that on average a reduction of reflectance (or gain in transmission) of 1.8% was obtained. In certain areas of the ARC covered TCO glass a reduction of reflectance of 2% could be obtained, most of the sample presented a gain of 1.8 to 1.9%. By further fine tuning of the process parameters a reflectance reduction of 2% over the whole area is supposed to be achievable.Once to potential of the ARC was determined AGC has performed respective cost evaluations for the investment into an ARC processing line for very large area TCO substrates as used in the T-Solar module production.The calculation was based on the following numbers:- Expected reflectance reduction (resp. transmission gain): 2%- Expected solar panel efficiency (tandem type): ~10%- Module price: 1 EUROS/WpThe power of a tandem-type silicon thin film module at 10% efficiency at that time was estimated to be 100 Wp/sqm. The estimated power gain by reduction of the reflectance by about 2% amounts to 1-2 Wp/sqm. At a module price of 1 EUROS/Wp, the benefit of these extra 1-2 Wp amounts to 1-2 EUROS/sqm. Admitting that this benefit would be shared 50/50 by AGC and its customer, this would mean for AGC an additional revenue of 0.5-1 EUROS/sqm. The deposition of such an antireflective coating on a TCO involves additional costs, especially as this coating cannot be deposited in the same production line as the TCO coating (which is done directly in the float line), but e.g. the TCO-glass must be turned around and transferred to another process line.Concerning the additional costs incurred for an ARC coating process the following has to be considered:- Investment of large-scale sol-gel coating line (a small pilot line already costs approximately 500 k EUROS)- Operating costs of coating line- Additional transport and handling costs- Overall yield lossThere exist some data in crystalline silicon PV technology about the additional cost incurred by a crystalline silicon module producer for using anti-reflective coated glass instead of normal glass which was reported by Centrosolar [CENTROSOLAR Group AG, Investor Presentation, November 2009] to be approximately 7 EUROS/module. For a typical module size of 1 to 2 sqm this corresponds in average to 7 EUROS/1.5 sqm = 4.7 EUROS/sqm. This is more than two times higher than the expected price difference that could be obtained for our case on a tandem-type silicon thin film module. Although the cost figure reported above for the anti-reflective coating is already 3 years old it seems unrealistic that it would have been reduced by more than 50% in the meantime. In general, on crystalline silicon modules with higher cell efficiencies the cost of ARC is more easily justified as the total gain in power due to reflection reduction is higher than on thin film solar cells. In consequence of the cost evaluation, the production of TCO glass with an sol-gel ARC coating was not implemented by AGC on large scale however, an alternative technology was identified that could be applied on a float glass line and first experiments performed within the project presented promising results. In consequence of the negative result of the cost evaluation, no prototype TCO modules including a TCO glass with sol-gel ARC could be produced in T-Solar.Task 2.2 Laboratory scale textured SiOx ARC by sprayAt the University of Barcelona (UB) a SiOx sol-gel solution was deposited on lab scale glass substrates by spray-coating and texturing was done by hot-embossing process which consists in the replication of a master onto this polymeric or gel-like coating. Thermal curing treatment is necessary to eliminate the organic molecules and to rigidify the film. To synthesize SiOx materials Si(OR)[sub(4)] and R-(SiOR)[sub(3)] precursors were used. The homogeneous low temperature deposition and texturing of ARC on lab-scale was achieved with a uniformity of about 5% on 10 cm x 10 cm substrates. These films show high diffused transmission, especially in the wavelength range higher than 700 nm, which is beneficial for the light scattering into the thin film solar cells. The as-deposited films were successfully textured by the hot embossing process. The deposition and embossing process parameters were optimised in such a way that this layer can be implemented into the fabrication of amorphous silicon thin film solar modules, e.g. using the autoclave process which forms part of the module lamination process. The perspective and main attraction of the here developed process is the flexibility to replicate any type of master texture to the ARC and to evaluate its improvement in the light scattering and light absorption in silicon thin film solar cells.Work Package 3: Glass/TCO interfaceTo get a baseline of the performance of different TCO glasses in amorphous single junction solar cells, at the beginning of the project benchmark tests were performed by the different laboratories with a variety of TCO glasses available within the consortium. At the beginning of the project, the standard TCO glass of AGC produced in large volume production was so-called 'AN10' TCO glass which was further improved in two development cycles to 'ANS10ME' TCO glass mainly increasing the transmission of the TCO glass. In this framework, prototype TCO glasses from AGC were tested several times in the TS production line to find the best TCO glass and to optimize the module fabrication process to this TCO glass. In a third development cycle the introduction of an interface layer (IFL) to reduce the reflection loss at the TCO-layer/p-layer interface was investigated.Task 3.1 Benchmarking of commercial TCOs with ZnO developed at FZJ and validation of TCOs developed in task 3.3At the beginning of the project, a number of commercially available (Asahi-U, AN10, NSG/Pilkington) and experimental TCO-glasses provided by AGC (Asahi-VU, AN10+ARC with anti-reflection coating (ARC)-, AN10ME with mobility-enhanced (ME) TCO layer-, ANS10 extra clear glass with low iron-content) were benchmarked at the different laboratories with their standard solar cell process for a-Si:H single junction solar cells. In this first benchmarking, the Asahi-U TCO-glass and the industrial TCO-glass with low iron-content (AGC ANS-type) presented the highest solar cell efficiencies. The high efficiency with the Asahi-U TCO-glass was not surprising, since the solar processes of the laboratories have been optimized for the Asahi-U TCO-glass. The good results found with the low iron-content substrate glass indicated that the implementation of low iron-content glass could be cost effective not only for a-Si:H/mc-Si:H tandem modules, but also for a-Si:H single junction modules. Furthermore, this first benchmarking showed the difficulties associated to the implementation of an ARC layer on the front side of the TCO-glass by the low efficiency of the devices suffering from contamination problems. In a second benchmarking experiment the solar cell processes of different laboratories were compared with a cell process similar to the TS fabrication process i.e. the thickness of the i-layer in the p-i-n structure was fixed to 200 nm. The objective was to find out the potential of improvement of the TS solar cell when compared to laboratory high efficiency processes. This gave a guide line for the optimization of the solar cell fabrication process in the TS production line. In a third benchmarking the effect of light-induced degradation (LID) of solar cells fabricated with the standard laboratory processes and different TCO glasses, including the new developed ones, was investigated. Here the dependence of the LID on i-layer thickness was determined. [M. Vetter et al., Proc. 27th European PVSEC 2012, Frankfurt, p. 2594] A fourth benchmarking was performed to investigate and to optimize a new type of TCO layer developed by AGC with enhanced carrier mobility (ME-type) which resulted in reduction of the TCO layer thickness and higher layer transparency. This layer then was combined with low iron content glass resulting in the ANS10ME TCO glass. Table presents the electrical parameters of 1 sqcm solar cells at standard test conditions (STC) fabricated in the TS production line at the beginning and at the end of the project. In the stabilized state the solar cell efficiency improved by more than 12% from 7.32% to 8.22%.In a fifth benchmarking the performance of ZnO:Al TCO glass developed at FZJ was investigated in the a-SiH single junction device. For this purpose, ZnO-based TCO glasses require a different device structure than SnO[sub(2)]-based TCOs, namely a p-doped mc-Si:H/a-Si:H layer stack must be included to provide a good electrical contact between the p-doped layer (p-layer) and the ZnO:Al-layer Single junction a-Si:H p-i-n solar cells have been deposited at FZJ on their in-house ZnO:Al TCO-glass and on Asahi-U TCO-glass as reference. The device structure of both sets of cells is identical (i-layer thickness, back reflector, etc.) except for the p-layer structure. The implemented p-layer is the optimized one for each TCO-glass for single junction a-Si:H cells: amorphous single p-layer on Asahi-U and double structure p-doped mc-Si:H/a-Si:H on ZnO:Al. The efficiency of cells on ZnO:Al TCO-glass was found to be about 10%relative lower than on Asahi U TCO-glass. A lower fill factor (FF) on ZnO:Al TCO-glass was due to the unfavorable contact between the zinc oxide layer and the p-doped thin film silicon layer. This effect is well-known and the reason that a multi-stack mc-Si:H/a-Si:H p-layer is used on this TCO-glass. If a single a-Si:H p-layer had been used (like on Asahi-U), the FF value would have been even lower. A higher open circuit voltage (Voc) measured on ZnO:Al was always observed on this kind of devices. The root cause of the effect was not found and is still under investigation. Morphology of the ZnO:Al-layer may be the reason behind this increased Voc. The lower Jsc measured on ZnO:Al, comes from different effects: higher light absorption in the mc-Si:H/a-Si:H p-layer double structure, and maybe in the ZnO:Al-layer as well, and the fact that in single junction a-Si:H p-i-n solar cells, one does not fully benefit from the light trapping of the ZnO:Al front TCO-layer, since this kind of TCO-layer is optimized for mc-Si:H and a-Si:H/mc-Si:H tandem devices, where light trapping is more essential in the longer wavelength range as compared to a-Si:H single junctions.Task 3.2 Process development of front TCO by small-scale in-line APCVD and Task 3.6 Development of TCOs with graded optical propertiesThe work in these two tasks was addressed to an important issue concerning the interface between the thin film silicon layers of photovoltaic cells and the TCO layer of the substrate. The TCO layer that is used consists of fluorine-doped tin oxide and has a refractive index of n=1.9 (at a wavelength of 600 nm). Silicon thin films however have a much higher refractive index of about 3 to 4.5 (at a wavelength of 600 nm). The result is that some of the light is reflected upon reaching this interface and can therefore not be harnessed by the photovoltaic layers. From the Fresnel formulae (which are valid only for smooth interfaces), the reflectance of the light would be theoretically zero if n[sub(TCO2)] = (n[sub(TCO1)] x n[sub(a-Si])[sup(1/2)] and 4 x.n[sub(TCO2)] x d = L, where, n[sub(TCO2)], n[sub(TCO1)] and n[sub(a-Si)] are the refractive indices of the intermediate TCO, front TCO and silicon p-layer respectively. The thickness of the intermediate TCO layer and the wavelength of incident light are presented by d and L.From literature was known that the addition of a high refractive index layer as e.g. TiO[sub(2)] (n=2.6) on top of the tin oxide TCO layer helps to reduce the reflectance at the TCO/Si interface. However, it has been found that TiO[sub(2)] presents two major issues. One is that it is not sufficiently conductive, thereby introducing an additional series resistance in the electrical circuit of the solar cell. Secondly, TiO[sub(2)] can lead to additional absorption depending on deposition conditions.At UB, Nb-doped TiO[sub(2)] (NTO) films were deposited at room temperature by rf and dc magnetron sputtering over Corning 1737F substrates in order to optimize their properties before using them as second TCO layer in the graded index structure. When NTO films were annealed at temperatures higher than 350 ºC, their crystalline structure changed to anatase phase and the films became conducting. Deposition parameters (rf or dc power applied, O[sub(2)] partial pressure and doping level of the target) and different post-annealing treatments (duration, temperature, atmosphere) were explored to optimize film properties, i.e. to minimize optical absorption in the spectral range of interest for a-Si:H and a-Si:H/mc-Si:H tandem cells and to get a conductivity high enough to avoid increasing the cells series resistance. The optical transmission spectra showed negligible free carrier absorption and this gave a wide scope for the utilization of this TCO layer for different applications. The reduction of the reflection losses at the TCO/a-Si:H interface was verified by depositing on the Asahi U/NTO stack a 200 nm a-Si layer and a 200 nm Ag layer back reflector in order to reproduce, from the optical point of view, the behaviour of a real device. The electrical resistivity of the thin NTO layer (40 nm) was 2x10[sup(-3)] ohm cm. There was only little change in sheet resistance when NTO was deposited on Asahi U substrates and hence, no significant contribution to the series resistance of the cell is expected with this additional coupling layer. The sheet resistance of the Asahi U was 8.5 ohm/sq and it was 9 to 9.5 ohm/sq for the NTO layer deposited on Asahi U substrate.Task 3.4: Implementation of developed TCO in very large area modulesIn this task several front transparent conductive oxide (TCO) glasses developed by AGC have been tested in large area (2.2 x 2.6 sqm) modules at the production line at T-Solar. These TCO glasses had already been characterized, tested and benchmarked in small scale cells as described in tasks before. The evolution of the average efficiency of the module production at TS can be seen. The increase in efficiency from 6.68% (382 W, BKM15) to 7.34% (420 W, BKM25) at the end of the project, almost a 10% relative increase, is the result of an improvement in the properties of the TCO glass (ANS10ME has become the standard T-Solar production TCO glass in the meantime) together with an improvement of the device (optimization of the different layers and adaption to the new TCO glass, laser process improvement, etc.).Task 3.5 Textured TCOs by embossing of sol gel coatingsIn this task the UB has explored the possibility of using spray technology to deposit ZnO layers from sol-gel solutions, and then applying hot embossing to transfer a surface texture to the films. The novelty of this method is to obtain TCOs with a tailored surface morphology in order to optimize their optical performance as front contacts in thin silicon solar cells. Unlike conventional spray pyrolysis of TCOs that involves spraying of a solution containing precursors onto a substrate heated above 400 °C, here the approach is to prepare a sol-gel of ZnO and deposit the film at low temperature (85 °C) to allow the embossing of the film. Additional thermal treatments may be needed after embossing to remove organic solvents. The master used for the hot embossing was a nickel hologram plate (5 x 5 sqcm) with randomly distributed periodic texture.Work Package 4: Intermediate reflector (tandem structure)The incorporation of intermediate reflecting layers (IRLs) has a great potential for the optimization of tandem solar cells with a-Si:H top cell and mc-Si:H bottom cell. Intermediate reflectors (IR) are used to provide selective light distribution, one of the three important mechanisms (the other two are light diffusion by the front TCO and reflection at the back reflector) for light management inside thin film solar cells. As the incorporation of IRL influences both the optical and the electrical properties of the whole device, the impact on the solar module performance is a complex topic. Due to the higher band-gap energy of a-Si:H, a photon, which is absorbed in the top cell provides a higher electrical power as in the bottom cell. Task 4.1 Demonstration of small tandem modules with intermediate reflectorThe first step of the incorporation of intermediate reflectors in very large area thin-film technology was the demonstration and optimization of IR materials on laboratory scale. At FZJ, silicon oxide layers were used as IR in a-Si:H/mc-Si:H tandem structures. The material parameters of microcrystalline silicon oxide''mc-SiOx:H) layers were investigated and were optimized. The optimum properties are an electrical conductivity (s) in the range s=10[sup(-4)] -10[sup(-2)] S/cm, a refractive index (n) in the range of n=2.2 2.6 and an optical band gap (E[sub(04)]) of E[sub(04)]=2.2-2.4 eV. The optimum layer thickness for the IRL is around 30-100 nm.Task 4.2 Development of suitable materials by PECVDAt the beginning of the project an exchange of tandem cells and IR structures between UU and FZJ was performed within this task. The purpose of this exchange was to implement a baseline for IR at UU by using n-type SiOx IR already developed by FZJ and to adapt this IR structure to the best tandem cell produced in UU. After testing several top cell i-layer thicknesses and two different IR thicknesses the best UU tandem cells with IR were obtained for 150 nm i-layer, 1.5 'm bottom cell and a 32 nm or 65 nm IR layer. These cells showed almost matched top and bottom cell currents due to the IR and thus the best values for the efficiency. In this frame, a tandem cell fabricated in UU with IR deposited in FZJ achieved an initial efficiency of 9.22% with 65 nm thick IR while the respective cell without IR presented a lower efficiency of 8.48% (150 nm i-layer thickness in the top cell and 1500 nm i-layer in the bottom cell) demonstrating that the IR concept works well in the UU tandem cell. The sample exchange process also showed that such sample transfer and multiple depositions at different laboratories with intermediate air breaks and sample handling has no significant effect on the cell performance due to robust nature of the device structure with IR and this was used as a guiding principle for sample exchange in Task 4.3. ZnO as IR was also tried in the UU tandem cell structure. ZnO layers, optimised for this purpose, showed significant reflection to the top cell, however, further development was needed to reduce the optical absorption loss in the ZnO IR layer.Task 4.3 Testing of intermediate reflector developed at laboratory scale at TS production lineThe objective of this task was to test the intermediate reflector layer concept in a-Si:H/mc-Si:H tandem structures at an industrial level. Two types of intermediate reflector materials have been considered in the project. One of the materials considered as IR is sputtered ZnO, a material which is the production standard in the back reflector structure in TS single junction modules and, therefore, was already available on large scale in the TS production line. ZnO layers, when moderately doped, are highly transparent in a wide wavelength range and provide sufficient transverse conductivity to conduct the current flow from the top cell to the bottom cell. Work Package 5: Back reflectorThe state-of-the-art back reflector deposition of the TS production line is by dc sputtering of ZnO:Al followed by an Al metal layer. The back reflector along with the front TCO plays a crucial role in p-i-n type thin film silicon solar cells by increasing the optical path of light inside the device, resulting in short circuit current gain. In the optimum doped ZnO/metal back reflector the doped ZnO layer should have low absorption and sufficient conductivity and the ZnO/metal interface should provide a high reflectivity and a low ohmic contact resistance.Task 5.1 Evaluation of the process conditions and modifications that can improve the state-of-art T-Solar back reflectorThe objective in this task was to evaluate the performance of the current back reflectors (BRs) of the laboratories (UU, UB, FZJ), who in particular applied an Ag-layer in the BR, in TS single junction a-Si:H cells and to give an accelerated feed-back for the possible efficiency gain which could be achieved in large area modules using an alternative BR structure. The efficiency gain due to an exchange of the standard Al-layer by an Ag-layer in the back reflector was found to be approx. 5%. However, the cost analysis showed that the Ag price of about 700-900 EUROS/kg was too high to implement the Ag-deposition into the TS production line. Then, it was investigated if it is possible to reduce the thickness of the Ag layer e.g. by applying a stack of Ag and Al layer. The use of a very thin (50-100nm) layer of silver in a stack TCO/Ag/Al/NiV as BR could also improve about 5% the efficiency of the modules. However, reliability aspects have to be investigated in detail before implementing the stacked layer.Task 5.2 Development of ZnO:Al/Ag back reflectors for single junction solar cells by sputtering from ceramic tube targets and Task 5.5 Benchmarking of the single junction solar cells with newly developed back reflectorsThe aim of this task was the development of ZnO:Al layers for the back contact in thin-film silicon solar cells with an industrial compatible process and improved properties. The main improvements are expected to be a higher deposition rate and a higher optical transmittance of the layers by a reduced doping concentration. Furthermore, the rotatable target technology presents a higher material utilization rate and therefore results in less maintenance time for the target exchange in a high volume production. The better yield of the rotatable targets in comparison to flat targets results in a reduction of production cost however, it has be balanced with a higher cost of the target fabrication.Task 5.3 Development of ZnO:Ga/Metal back reflectors for single junction solar cells by rf magnetron sputteringGa-doped ZnO layers (ZnO:Ga) layers were characterized and optimized at the UB, where trials onto cells fabricated at UB and onto 10 x 10 sqcm coupons with the pin structure of TS were performed. Different problems arose during the project when TS p-i-n structures were used at UB or FZJ. Given that the exposure to air of an n-layer causes the oxidation of the interface, a bad device performance was unavoidably found after the standard transportation of the cells from TS and finished to solar cells in another laboratory consisting in an S-shape of the current voltage (J-V) curves near the point of open circuit voltage (Voc), giving a poor fill factor (FF), and a lack of reproducibility of the results. To overcome the problem, coupons from TS were then delivered with either a very thin protection layer of standard ZnO:Al TCO-layer over the p-i-n structure or in an inert gas environment like nitrogen or vacuum. After experimenting with the back reflector deposition from many different approaches it can be concluded that it is so far not possible to deposit a proper TCO-layer on a pin structure in a different place than where the active part of the device was fabricated. E.g. in the TS production line the time between p-i-n deposition in the PECVD machine and the BR-deposition in the PVD machine typically is between 1-4 hours and is mainly due to the time needed to cool down the panels from about 200ºC to ambient temperature. In this time the panels are stored in clean room with controlled 50% humidity. The reason is the formation of a thin oxide layer on top of the n-layer which appears when silicon is in contact with air. This thin oxide layer changed with time. Once the problem was identified, the layer was tried to be removed by chemical or reactive ion etching obtaining non-reproducible results. Task 5.5 Benchmarking of the single junction solar cells with newly developed back reflectors and Task 5.6 Transfer of the optimised back reflector deposition technology to large area modulesThe objective of Work Package 5 was to improve the industrial back contact structure implemented in the T-Solar production line. This back contact structure consists of a thin sputtered low Al-doped ZnO-layer (ZnO:Al) and a thin sputtered Al-layer followed by a thin NiV layer. The back contact structure has multiple electrical and optical functions as e.g. the extraction of the electric current from the p-i-n-structure, and the reflection of light which has not been absorbed in the p-i-n structure in the first pass. The industrially implemented back contact structure is a compromise among the cost of materials and fabrication, the deposition speed in production, and the desired physical properties of the layers which finally impact on the efficiency of the solar cell device. Apart from the materials which are implemented in the back contact structure also the deposition technology has an impact on the solar cell efficiency due to the physical properties of the layers and the layer interfaces.In order to develop new materials and new deposition technologies for producing efficient back reflectors, systematic studies were carried out by UB and FZJ to develop back reflectors with the objective to produce higher efficiency in TS single junction a-Si:H solar cells. In this project, Ga-doped ZnO (ZnO:Ga) at UB and Al-doped ZnO (ZnO:Al) at FZJ, were considered for the back reflector stack. These materials have been deposited by two different techniques; rf magnetron sputtering at UB from planar target and DC magnetron sputtering from ceramic tube targets at FZJ. Furthermore, two different metal layers, aluminum (Al) and silver (Ag) have been used in the back reflector by UB and by FZJ to determine the difference in electrical and optical performance in solar cells and to evaluate the advantages or disadvantages of each layer for industrial application. The metal layers have been deposited by magnetron sputtering and thermal evaporation.The first conclusion that can be drawn from these experiments is that packaging and shipment of the p-i-n coupons lead to a poorer electrical behavior of solar cells compared to those produced inline mainly due to native silicon oxide formation of the n layer of the p-i-n structure. Typically, lower FF and higher series resistance values have been found in solar cells prepared after transportation. Nevertheless, the use of a ZnO:Al layer DC sputtered from rotatable target presented comparable results to the planar targets presently used in TS, but with rotatable targets a better yield of the target material is achieved what makes this process interesting for industrial application. In the case of ZnO:Ga layers, although a slight increase in Jsc could be detected, results are also very close to those of ZnO:Al deposited by the same technique.The two main conclusions of the studies that can be drawn from this work package are:1) The deposition of the back reflector TCO must be carried out inline to prevent any issue with contamination and the native silicon oxide formation on the p-i-n structure. Only under this condition, an exact value of the efficiency gain can be determined. The type of TCO layer (ZnO:Al or ZnO:Ga) and the deposition technique applied (planar or rotatable target) is of secondary importance for the efficiency gain and should be selected according to the process with lower overall implementation costs (target cost, yield, maintenance etc.).2) The key issue in improving the back reflector performance is the metal layer used in the first 50-100 nm of the back reflector. The use of a very thin layer of silver in a stack TCO/Ag/Al/NiV as back reflector could improve about 5% the efficiency of the modules. However, reliability aspects have to be investigated in detail before implementing the Ag layer. The evolution of the Ag price and the overall module production cost has strong impact on the cost effectiveness of the implementation of the Ag layer. In the graph it can be seen that increasing the silver price beyond 600 EUROS/kg to about 850 EUROS/kg reduces the benefit by about 1% when using an Ag layer in the back contact.Work Package 6: Advanced characterization methodsIt was the aim of the project to increase the efficiency of thin film solar cells by improving the light trapping efficiency and by reducing parasitic losses. The improvement in the light trapping is achieved e.g. by antireflection coatings at the front glass surface, the optimization of the surface morphology of the front TCO layer, the implementation of intermediate reflectors (in the case of tandem solar cells) and the improvement of the back reflector. Standard methods for the characterization of solar cells are the measurement of current voltage curves and external quantum efficiency as reported in former work packages. Task 6.1 Characterization of surface morphologyObjective of this task was to support the development of new improved TCO layers by providing additional information about the morphology of the TCO layer. Knowledge about the TCO morphology and the correlation with its optical properties helps to interpret the electrical results of solar cells prepared on the TCO glasses. At the beginning of the project, basically 4 different glasses with TCO layers were available in the consortium: NSG/PKT (large volume industrially produced TCO glass provided by NSG/Pilkington, Japan), AN10 (large volume industrially produced TCO glass provided by AGC, Moustier, Belgium), Asahi U (commercially available TCO glass for laboratory purpose provided by AGC) and Asahi VU (experimental TCO glass provided by AGC). The morphology of these substrates was investigated at the beginning of the project. In the images one sees the typical microcrystalline structure of Sn[sub(2)]-type TCO layers grown at temperatures higher than 400ºC. In the top view the dimension of the crystal grains ranges from about hundred nanometers to about half of a micrometer. Task 6.2 Measurement of the properties of individual materialsObjective of this task was to obtain the optical properties (given as refractive index n and absorption coefficient ''in function of the wavelength (or respective energy) of different amorphous and microcrystalline silicon layers manufactured by TS, UU and the FZJ. These optical properties are necessary for understanding the optical as well as the electrical characteristics of solar cells containing these materials. The optical data was obtained using a combination of photothermal deflection spectroscopy (PDS) and spectroscopic ellipsometry. While PDS measurements deliver a very precise absorption coefficient for values up to 10[sup(5)]/cm, it is possible to obtain the refractive index n and the absorption coefficient for values above 10[sup(5)]/cm via ellipsometry.Task 6.3 Correlation of local light trapping behaviour and solar cell performance by experimentTextured surfaces are used to improve the light absorption in solar cells. The improvement is attributed to light scattering at the rough interfaces (e.g. at the TCO/silicon interface for transmission and at the silicon/back reflector interface for the reflection). A further optimization of the light scattering needs a detailed knowledge about the scattering properties of individual surface features of the statistically rough interfaces (roughness in the nm to 'm scale). To provide this knowledge, an optical near-field analysis was done in this task. The analysis is done by near-field scanning optical microscopy (NSOM) experiments in combination with optical simulations based on finite-difference time-domain (FDTD) method. From this, the evanescent part of light as well as the local light absorption in the silicon is extracted. Light that is totally internally reflected shows an exponential decrease in intensity in the surrounding medium. These are the evanescent modes that reflect the intensity of the guided optical modes inside the layer. Therefore, these modes are taken as a benchmark for the light trapping in the solar cell, since NSOM experiment is only possible in the outer medium air and not inside the silicon. In contrast, the optical simulations allow also studying the local absorption inside the silicon. Therefore, the combination of both methods provides important knowledge about the light trapping properties of individual surface features.Task 6.4 Durability test of ARCIn the framework of WP2, two different approaches for anti-reflecting coatings (ARC) deposited on the front glass of the superstrate (TCO-covered glass) of a-Si(:H) thin film modules were investigated. The first approach consisted in the deposition by high temperature sol-gel based processes carried out by an in line process performed during or after the manufacturing of the TCO-covered front glass (TCO-glass). The second approach consisted in low temperature spraying and curing of sol-gel solutions. In addition, the development of the SiOx coatings and their texturing by hot-embossing lithography by this second approach was performed. The first approach, on the one hand, has the advantage of being an established method that produces a clear increase in optical transmission of the superstrate, e.g. the cover glass of crystalline silicon modules. On the other hand, since it is a high temperature process, the ARC has to be deposited before p-i-n silicon layers deposition, and the ARC must be compatible with the vacuum deposition process and eventual contamination of silicon layers has to be checked. The second approach presents the advantage of being applicable after finishing module fabrication process. Task 6.5 Infrared inspection of very large area modulesIn the solar module production process of T-Solar efficiency losses due to resistive losses can appear at different places in a solar module, e.g. resistive heating under current flow can occur in electrical contact areas due to incomplete soldering of the buss bars, in small shunts in the pin structure or due to failures in the laser scribing process. The here applied method is to inject an electrical current into a module and to detect the electrical power losses of the defects in form of radiation with a camera. The radiation can result from resistive heating e.g. produced in shunts or from electroluminescence radiation emitted from the solar cell operating in so-call "forward conditions". The radiation is typically in the infrared wavelength range. These investigations were carried out first on a laboratory level with quarter size modules (1.1 m x 1.3 m). Several experimental studies were performed in order to correlate the appearance of defect structures in the images of modules with variations in the production process. So, several defects resulting from errors in the production process causing shunts have been identified and were related e.g. to the laser scribe processes, to dust particles etc., in addition the electroluminescence radiation from modules could be photographed. It was demonstrated that infrared imaging can contribute significantly to the quality assessment of the module production process. Then, the implementation of an in-line camera inspection system for full size (2.6 m x 2.2 m) modules was demonstrated. Two camera systems, one applying CCD chip technology , (Hamamatsu, silicon technology), sensible in the NIR wavelength range, and another camera system applying lock-in thermography (Thermosensorik, LIT), using an InSb chip sensible in the MIR wavelength range, were evaluated for module quality assessment. The experimental set-up of LIT is much more complicated and about a factor of five more expensive than the CCD camera set-up, however, both methods are complementary and in principle able to detect the same defects in modules. Since the CCD technology presents before mentioned cost advantage experimental work was concentrated on this technology. After the determination of the optimum range of current and exposure time for the acquisition of images and other experimental details off-line in the laboratory, a Hamamatsu Orcaflash 4.0 camera was installed in the solar simulator of the T-Solar production line. The solar simulator is an excellent place for this kind of camera inspection, since it is a completely enclosed dark space and the module is connected electrically to measure the current voltage (IV) curve under standard test conditions. So, for the acquisition of the images only a switch has been to be introduced in the electric measurement system to disconnect the IV curve measurement system and to connect a current source to inject the current into the module. One sees only the electroluminescence radiation homogeneously distributed and eleven dark horizontal lines are visible resulting from so-call hot-spat laser scribes to protect the module for high current flow under partially shadowing conditions. The laser scribe design results in 12 parallel blocks of 216 one cm wide solar cells connected in series. Other marks and lines on the module seen in the photo are artifacts resulting from parasitic light entering the solar simulator box. On the right side one sees a photo of a module from a test series of prototype TCO glass with TiO2 interface layer (IFL) performed in WP3. With the IFL layer the process parameters of all laser scribe process needed to be newly adjusted which was not done successfully for the here shown module and is nearly impossible to detect in this detail with any other method. It seems that due to the slightly thicker layers of the p-i-n structure in the middle of the module the P2 and P3 laser scribe are not processed with adequate energy resulting in shunted cells indicated by the black lines (or black cells). In this way, high resolution images where every 1 cm wide solar cell can be identified in a 5.7 sqm module can be generated in the solar simulator. By injecting forward currents into the module in the range of about 1-3 A and applying exposure times from a few seconds to one minute, data acquisition times are achieved well below the production tact time of 3 minutes per module in the solar simulator. The implementation of such a CCD camera system is very easy to perform in the solar simulator box and presents a very low cost solution providing an excellent assessment of the electrical quality of each module at the end of the production process. It presents an excellent method especially to control the laser scribe processes performed in each module.Potential Impact:In the frame of the dissemination activities, three articles presenting work performed within the HELATHIS project are published by the project partners in peer-reviewed journals (J. App. Phys., J. Non-Cryst. Sol., Mat. Sci. Eng. B) so far and eight contributions were presented in conferences and are published in the respective conference proceedings (EU-PVSEC, ICANS, E-MRS, CDE), three of them were oral presentations. Another two contributions were presented in February 2013 in the Spanish Conference of Electronic Devices (CDE) 2013 and will be published in the next weeks. TS published several press releases during the last years e.g. when the project started or about the publications on conferences. To promote the distribution of the publications of the HELATHIS project the respective data have been introduced on the OpenAIRE portal created in the frame of the Seventh Framework Programme (FP7) project "Open Access Infrastructure for Research in Europe" (FP7 Infrastructures, GA 246686). Apart from this, the HELATHIS project was presented in four workshops by the coordinator, reporting on the progress of the scheduled work (1st EU PV-Cluster Workshop "Photovoltaics and Nanotechnology, Sept. 2010, Aix-les-Bains, France; Spanish Workshop "Energía en el Programa Marca de IDT", organized June 2011 within the EU-Project ER-INNOVA, Ferrol, Spain; European Energy Research Alliance (EERA) Workshop, Oct. 2011, Berlin and 4th International Workshop on Thin-Film Silicon Solar Cells (IWTFSSC-4), March 2012, Neuchatel, Switzerland).Exploitation of the project results has been made in very large volume production on industrial level of TCO glass by AGC and silicon thin film modules by TS. On the one hand, development of ANS10ME TCO glass for large volume production has been a great success since, apart from the increase in module efficiency in the T-Solar production to nearly 8%, during the operation of the project the whole module production of Applied Materials SUNFABs in Europe (T-Solar Global 40MW corresponding to approx. 700.000 sqm TCO glass per year, Signet Solar 25 MW, Masdar PV 40MW, SUNFILM 60MW, Malibu 40MW, Moncada Energy 40MW) had changed from formerly in Japan produced NSG/Pilkington TCO glass to TCO glass produced in Moustier, Belgium, which has resulted in a big impact on the European economy.List of Websites:http://www.tsolar.com/helathis Related documents Final Report - HELATHIS (High Efficient Very Large Area Thin Film Silicon Photovoltaic Modules)
