Hybrid Solar Cells Based on Nanoparticles of CuInS2 in Organic Matrices

We report on solution‐processed hybrid solar cells consisting of a nanocrystalline inorganic semiconductor, CuInS2, and organic materials. Synthesis of quantized CuInS2 nanoparticles was performed using a colloidal route, where the particle surface was shielded by an organic surfactant. First attempts were made to use nanocrystalline CuInS2 with fullerene derivatives to form flat‐interface donor–acceptor heterojunction solar cells. We investigated also bulk heterojunctions by replacing the CuInS2 single layer by a blend of CuInS2 and p‐type polymer (PEDOT:PSS; poly(3,4‐ethylenedioxythiophene:poly(styrene sulfonic acid) in the same cell configuration. Bulk heterojunction solar cells show better photovoltaic response with external quantum efficiencies up to 20 %. Combining nanocrystalline CuInS2 with organic materials, heterojunction solar cells have been fabricated by spin‐coating. Promising cell performance is achieved in double‐layer configurations of CuInS2 and fullerene derivatives with an external quantum efficiency of ∼ 5 %. Bulk heterojunctions are also studied by replacing the CuInS2 single layer with a blend of CuInS2 and p‐type polymer in the same cell configuration, with a significant increase of the external quantum efficiency up to 20 %.