Highly conductive CdS inverse opals for photochemical solar cells

Abstract

Semiconductor materials with an inverse opal structure have previously demonstrated promise for photovoltaic applications. However, their use in solar cells is still restricted by their poor electron transfer properties. Here, highly conductive CdS inverse opal structures are prepared via a multistep process, where CdS inverse opal backbones are first built up on conductive glass substrates via co-deposition of CdS quantum dots and polystyrene microspheres, followed by calcination, after which subsequent electrodepositon and annealing treatments are applied to transform the fine constituent nanocrystals into larger ones, thus considerably enhancing the electrical conductivity. The obtained CdS networks are tested as anodes in photochemical solar cells and demonstrate conversion efficiency values up to 2.00% under the illumination of one sun. After depositing an additional CdSe layer, the conversion efficiency of the structures is further increased to 2.47%.