Scalable synthesis of CuInS2 nanocrystal inks for photovoltaic applications

Abstract

Chalkopyrite copper indium disulfide (CuInS₂, CIS) nanoparticles in the range of 10 nm particle size have been prepared via hot-injection and precipitation by an easily scalable synthesis. The influence of reaction time and precursor composition on the nanoparticle properties was assessed. After surface ligand exchange CIS nanoparticle inks were deposited as thin precursor layers for CuIn(S,Se)₂ (CISSe) solar cells. Film formation, morphology and crystallinity after exposure of the CIS precursor layer to selenium vapour at elevated temperature have been investigated. Application of CIS precursors allows for a better control of the film composition, the lattice volume expansion by the exchange of S by Se during the selenization process minimizes the risk of voids. Solar cells made from CIS nanocrystal precursors gave power conversion efficiencies of up to 6.5% under standard AM1.5 illumination.