Periodic Reporting for period 1 - TRIUMPH (Triple junction solar modules based on perovskites and silicon for high performance, low-cost and small environmental footprint)
Reporting period: 2022-10-01 to 2023-11-30
The TRIUMPH project aims to initiate the development of a future PV cell technology node, based on an advanced triple junction cell concept, that is widely considered to be the next technology node to come after tandems. Presently, there is considerable amount of attention and research and development (R&D) activities devoted to Pk/Si tandems and already promising cell efficiencies, reliability and outdoor performance results have been obtained. The highest efficiency reported for a 2-terminal (2T) Pk/Si tandem is 33.9%, which has already gone past the Auger limit of Si. Therefore, in TRIUMPH, we plan to venture a step further than tandems by targeting TRIple junction devices, that can add the extra “OOMPH” (hence the name TRIUMPH) needed to reach efficiencies even >33%. These 2T triple junction devices will be based on perovskites for the middle and top cells and silicon for the bottom cell and will build on the knowledge garnered in the field of Pk/Si tandems. Additionally, cost-effective processing techniques that are industrially viable will be selected for scale-up developments, with minimal upscaling performance loss and degradation during reliability testing and outdoor monitoring. As we enter the tera-watt (TW) era of PV deployment, using earth-abundant materials and enforcing circularity become necessities. Towards this objective, we not only explore options that reduce critical raw materials (CRM) such as silver (Ag) and indium (In) in the triple junction devices, but also apply design for recycling principles to the triple junction modules. The consortium consists of 14 complementary partners from both research institutions and industry, each bringing their best forte to the table, which will help to establish the pathway and the value chain for future multi-junction modules. In this way, TRIUMPH would help the European Union (EU) to maintain its technological leadership in the PV domain for the future generation of PV technologies.
There are 4 specific objectives defined for the TRIUMPH project: (1) very high efficiencies, (2) cost-effective and scalable technology, (3) design for sustainability, and (4) value chain buy-in. The activities of the project in the first reporting period have addressed all these objectives to varying extents, but mostly devoted to this first and third objectives. The related WPs are WP3, 4 and 5 and Task 7.2. Activities in WP6 and all of WP7 except T7.2 are just starting up or yet to start, while WP8 is focussed mainly on data collection and preparing the framework for the analyses to be done in the remaining part of the project. Towards objective 1, the main achievements so far can be summarized as follows. A comprehensive opto-electrical model has been developed, which provides directions for the optimal bandgap and thicknesses for the top and middle Pk absorbers. This model predicted that the practical efficiency limit of Pk/Pk/Si 3J cells is 44.3%, assuming ideal electrical properties. Based on this, the building blocks of the 3J cell, i.e. the top, middle and bottom sub-cells were developed. In particular, a relatively photostable Pk absorber with an appropriate bandgap of 1.8 eV has been achieved. High-performant and stable middle and top cells, with appropriate bandgap as recommended by the modeling, have been realized. Putting these building blocks together, 3J cells with the best efficiency of 23.4% have been attained so far, which improved on the state-of-the-art of 12.7% before the start of the project. For evaluating and reporting the performance of 3J devices correctly, a reliable methodology for measuring the JV and EQE characteristics of 3J devices has also been established. Towards objective 2, upscalable technologies for Pk deposition are in development, and upscale routes for 3J modules have been identified. Towards objective 3, the main activities so far are the following. Considering the deployment of 3J technology in the TW-era, AZO as a replacement for scarce indium-containing TCOs has been developed using both spatial ALD and magnetron sputtering, with the latter even on a non-heated substrate (suitable for use on Pk materials). At module level, release encapsulant technology that was demonstrated previously for Si modules is being extended to tandem and 3J technology, whereby an encapsulated module can be triggered to release on demand, when using the release encapsulant. A release encapsulant laminated at low temperatures (< 150°C) has shown sufficient adhesion in the non-triggered state (more than 2x the 20 N/cm threshold), while demonstrating residue-free release upon triggering. Towards objective 4, all industrial partners have contributed to the project activities in this period. RENA provided additives to IMEC to achieve sub-micron Si texturing. Dyenamo expanded their portfolio of self-assembled monolayer (SAMs) for use as interface passivation to >20 types (called Dyenamo’s SAM factory) and made them available to consortium partners. VA worked on AZO by magnetron sputtering on non-heated substrates. SALD developed a spatial ALD recipe for AZO at 230 °C so far.
TRIUMPH has already improved the state-of-the-art in terms of 3J device performance from 12.7% (before the project) to 23.4% (current status), well ahead of the plan to achieve the project's high efficiency goal. The challenges addressed in the process of these developments can be continuously uptaken by companies involved in the project and could also have spill-over benefits in other business areas for the companies, e.g. tandem research and commercialisation by Qcells, addition of new SAM materials to Dyenamo's portfolio which is also interesting for the field of single-junction perovskites and tandems, indium-free TCOs as an option for Von Ardenne and SALD towards single-junction c-Si solar cells, single-junction perovskite solar cells as well as tandems. Progress has also been made towards bringing standardization for accurate and trust-worthy measurements for multi-junction cells and modules. This would benefit the community is reporting on the next-generation multi-junction devices in a way that allows for benchmarking across different entities globally. Insight into modeling of metastability and degradation in Pk-based multi-junctions are key enablers and solving those issues are critical for the commercialization of multi-junction technology, and progress is being made on these aspects as well within TRIUMPH. Lastly, sustainability in PV is crucial in the TW-era of PV depolyment and concepts for material sustainability and circularity are already being explored in this project. It is too early for the first reporting period to discuss about needs for further uptake and success beyond the end of the project at this stage.