Cu2ZnSnSe4 based solar cells combining co-electrodeposition and rapid thermal processing. (October 2018)

• Record Type: Journal Article
• Authors: Valdés, M.; Hernández-Martinez, A.; Sánchez, Y.; Oliva, F.; Izquierdo-Roca, V.; Perez Rodriguez, A.; Saucedo, E.
• Is Part Of: Solar energy. Volume 173(2018)
• Page Start: 955
• Page End: 963
• Publication Date: 2018-10
• Subjects: Co-electrodeposition -- Precursor -- Rapid thermal processing -- Kesterite -- Solar cells; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2018.08.049
• Languages: English
• ISSNs: 0038-092X

Abstract

Graphical abstract: Highlights: CZTSe are deposited combining co-electrodeposition of CZT films and RTP selenization. CZT compositions required for PV cells are achievable with a short deposition time. The use of RTP treatments reduces selenization time by a factor of 5, favoring cost and energy saving. Best solar cells achieve efficiencies over 5% and reaches quantum yields of 70–80%. Low open circuit value is attributed to the low quality of the Mo/CZTSe interface. Abstract: In this work, a fast two-step process combining co-electrodeposition of a CuZnSn precursor plus a reactive selenization step with a rapid thermal annealing to synthesize Cu2 ZnSnSe4 thin films is presented. By tuning the electrochemical procedure is feasible to obtain with a short electrodeposition time (15 min) the precursor composition required for high efficiency solar cell devices. XRD characterization reveals that the precursor is mainly composed of binary Cu-Zn and Cu-Sn alloys that after thermal treatment completely react to form a kesterite thin film. Raman spectra and Raman mappings demonstrate that best quality kesterite films are obtained after selective chemical etching necessary to remove secondary phases, like ZnSe and SnSe, which are detrimental for solar cell performance. Best solar cells prototypes achieve efficiencies of 5% with a current density of 30.9 mA/cm 2, an open circuit potential of 327 mV and a fill factor of 51.5%. The low value of open circuit voltage is attributed to the presence of voids and partial delamination observed in the Mo/Cu2 ZnSnSe4 interface.