Suchergebnisse

The effect of Zn content on compositional, structural and vibrational properties of Cu2ZnSn1-xGexSe4 (CZTGSe, x ~ 0.5) thin films is studied. Kesterite layer is deposited by co-evaporation onto 5 x 5 cm2 Mo/SLG substrate followed by a thermal treatment at maximum temperature of 480º C, obtaining areas with different composition and morphology which are due to the sample position in the co-evaporation system and to the non-uniform temperature distribution across the substrate. Kesterite layers with higher Zn amounts are characterized by lower Cu and Ge contents; however, a uniform Ge distribution through the absorber layer is detected in all cases. The excess Zn concentration leads to the formation of ZnSe secondary phase on the surface and in the bulk of the absorber as determined by Raman spectroscopy. When higher Ge content and no ZnSe are present in the absorber layer, a compact structure is formed with larger grain size of kesterite. This effect could explain the higher Voc of the solar cell. The Zn content does not affect the bandgap energy significantly (Eg near 1.3 eV), although the observed effect of Zn excess in CZTGSe results in a decreased device performance from 6.4 to 4.2 %. This investigation reveals the importance of the control of the off-stoichiometric CZTGSe composition during the deposition process to enhance solar cells properties. ; This work was supported by Spanish Ministry of Science, Innovation and Universities Project WINCOST (ENE2016-80788-C5-2-R) and European Project INFINITE CELL (H2020-MSCA-RISE-2017-777968). ARP also acknowledges financial support from Community of Madrid within Youth Employment Program (PEJD-2017-PRE/IND-4062). This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness(ACCIÓ).

We report the effect of an ultra-thin Al2O3 layer (down to 3 nm) as interface passivation strategy for the improvement of the performance of Cu2ZnSnS4/CdS based solar cells. After an initial optimization, the Al2O3 deposited by thermal evaporation is proved to improve the properties of the p-n junction. The fabricated devices showed an increment in Voc depending on the composition of the absorber, and an improvement in fill factor (FF) apparently related to the insulation of possible shunt-paths. Also, the impact on other optoelectronic parameters is discussed. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ). This research has also been supported by the H2020 Programme under the project INFINITE-CELL (H2020-MSCA-RISE-2017-777968), by the Spanish Ministry of Science, Innovation and Universities under the IGNITE project (ENE2017-87671-C3-1-R), and by the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007–2013). Authors from IREC and the University of Barcelona belong to the SEMS (Solar Energy Materials and Systems) Consolidated Research Group of the "Generalitat de Catalunya" (Ref.2017 SGR 862). M.P. thanks the Government of Spain for the Ramon y Cajal Fellowship (RYC-2017-23758). This research was also supported by Consejo Nacional de Ciencia y Tecnología (CONACYT) with the scholarship No. 433146 and with the project CB-CONACYT-255062. Finally, this research was also supported by Programa de Fortalecimiento de la Calidad Educativa (PFCE 2019) and by Project VIEP 2019.

This work has been published in Solar Energy 198 (2020) 696–703 (DOI:10.1016/j.solener.2020.02.009). In this work, we report the effect of an ultra-thin Al2O3 layer (down to 3 nm) as interface passivation strategy for the improvement of the performance of Cu2ZnSnS4/CdS based solar cells. After an initial optimization, the Al2O3 deposited by thermal evaporation is proved to improve the properties of the p-n junction. The fabricated devices showed an increment in Voc depending on the composition of the absorber, and an improvement in fill factor (FF) apparently related to the insulation of possible shunt-paths. Also, the impact on other optoelectronic parameters is discussed. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ). This research has also been supported by the H2020 Programme under the project INFINITE-CELL (H2020-MSCA-RISE-2017-777968), by the Spanish Ministry of Science, Innovation and Universities under the IGNITE project (ENE2017-87671-C3-1-R), and by the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007–2013). Authors from IREC and the University of Barcelona belong to the SEMS (Solar Energy Materials and Systems) Consolidated Research Group of the "Generalitat de Catalunya" (Ref.2017 SGR 862). M.P. thanks the Government of Spain for the Ramon y Cajal Fellowship (RYC-2017-23758). This research was also supported by Consejo Nacional de Ciencia y Tecnología (CONACYT) with the scholarship No. 433146 and with the project CB-CONACYT-255062. Finally, this research was also supported by Programa de Fortalecimiento de la Calidad Educativa (PFCE 2019) and by Project VIEP 2019.