Structure of CuInGaS2 nanocrystals for photocatalytic applications

Cu(In,Ga)S2 (CIGS) quantum dots (QDs) are semiconducting nanocrystals with optical properties of great interest for optoelectronic applications such as photocatalytic H2 generation due to strong light absorption, high stability, and absence of toxic elements. However, the role and place of gallium in these systems, which is critical to control the QDs properties, must be fully investigated. Through modulation of the reaction conditions and pathway, we are developing a panel of CIGS with differing ligands, compositions, passivation shells, and optimised optical properties. Via XAFS, we intend to study the local structure of Ga in these QDs (and synthetic intermediates) in various media. This information in conjunction with the photophysical and other characterisations will help us not only understand the effects of the reaction conditions on the structure and optical properties but also enable us to propose the best QDs for the photocatalytic H2 production from water.