Final Report Summary - KESTCELLS (Training for sustainable low cost PV technologies: development of kesterite based efficient solar cells)
From a scientific point of view the main achievement is that as far as technical aspects are concerned, CZTSSe has been identified as one of the most promising material for future thin films PV applications, which meets the requirements of abundance of the constituent elements, low toxicity level and a full compatibility with the standard processes employed for the PV community at present time. As a result, kesterites are now considered a potential alternative at medium and long term to the conventional CIGS technology, which presents the inherent problem of In and Ga scarcity. In the frame of the project, the fundamental properties of kesterites have been studied using different advanced characterization methods, including X-ray and neutron diffraction, Raman spectroscopy, photoluminescence and ellipsometry. In this sense, KESTCELLS has largely contributed to understand basic and applied characteristics of these materials such as the band-gap properties, the energetic position of the bands and ionisation energy of defects, the crystal structure and the structural origin of intrinsic point defects and the fundamental vibrational properties, as well as their dependence on the compound composition and growth process. This has been a significant step forward in the fundamental knowledge of kesterites. The project has also developed different approaches for the synthesis of high quality kesterite layers, which combined with the advancements on the re-design and optimization of the device structure, has allowed achieving solar cells with efficiencies in the range of 9-11%, and a record value of 11.8%. The project has also laid the foundations for the identification of characterization methods suitable for future development of on-line quality control tools, as well as the availability of a complete 2D model for the simulation of kesterite based devices. All these research activities have been complemented with the analysis of future industrialization of the technology.
In parallel, KESTCELLS has trained fourteen researchers through a customized programme, designed in accordance to each fellow needs. Fifty-six specific seminars, five specialized workshops, eight project meetings, two business schools, one summer school in photovoltaics, ten open day activities, three newsletters, twelve video-clips, and thirty-eight secondments have been implemented during the project, which demonstrates an outstanding training effort at network level. Thanks to all these activities, a broad training that goes beyond the scope that each institution is able to offer with own resources has been feasible. In consequence the fellows have received a notable training focused on scientific aspects and complementary soft-skills in management, IPR, communication, writing, reporting, business creation, entrepreneurship and others. The success of the training is validated by the large number of outputs generated, which include 147 contributions at international conferences (invited conferences, key note speeches, oral and poster presentations), and 82 papers in peer-reviewed journals.
In summary, KESTCELLS has demonstrated the potential of the kesterites based solar cells technology, increasing the TRL from 2 (basic technological research) at the beginning of the project, to 4 (validation at a laboratory level) at the end. Through an effective and fruitful scientific collaboration between research centers, universities and companies, most of the KESTCELLS’ ESRs have completed Doctoral Degrees enriched with a multidisciplinary training paying special attention to industrial aspects and interests. All in all, the project represents a step towards more integrated collaborative schemes in PV at EU level.
www.kestcells.eu
Contact Person: Dr. Edgardo Saucedo (esaucedo@irec.cat)