Influence of OLA and FA ligands on the optical and electronic properties of Cu2ZnSn(S,  Se)4 thin films and solar cells prepared from nanoparticle inks. (15th November 2018)

• Record Type: Journal Article
• Authors: Campbell, S.; Qu, Y.; Bowen, L.; Chapon, P.; Barrioz, V.; Beattie, N.S.; Zoppi, G.
• Is Part Of: Solar energy. Volume 175(2018)
• Page Start: 101
• Page End: 109
• Publication Date: 2018-11-15
• Subjects: Cu2ZnSn(S, Se)4 -- Thin film solar cells -- Photoluminescence (PL) -- Formamide; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2018.03.065
• Languages: English
• ISSNs: 0038-092X

Abstract

Graphical abstract: Highlights: PL properties of CZTSSe absorbers prepared using OLA and FA ligands were studied. PL analysis revealed different recombination mechanisms for OLA and FA absorbers. Working solar cells were fabricated using a stack of OLA and FA absorbers. The OLA + FA device has a reduced back contact barrier with lower R s and higher FF . The fine grain C layer at the back contact is removed improving device performance. Abstract: The use of formamide (FA) as an alternative capping ligand to oleylamine (OLA) during the preparation of Cu2 ZnSnS4 (CZTS) nanoparticle inks was investigated. Photoluminescence properties of the selenised CZTS absorber layers revealed quasi-donor acceptor pairs (QDAP) as the main transition for carrier recombination with similar electrostatic potential fluctuations in both type of ligands. In OLA layers the transition shifts from QDAP to band-impurity as temperature rises. Solar cell devices fabricated from FA Cu2 ZnSn(Se, S)4 were shunted due to the high porosity of the film while in contrast, the combination of FA + OLA absorber yielded reduced back contact barrier height, lower series resistance and higher fill factor and efficiency compared to OLA devices. This is a direct result of the removal of the fine grain carbon rich layer from the back contact interface usually present in films prepared with OLA only.