Co-evaporated bulk heterojunction solar cells with >6.0% efficiency.

High power conversion efficiencies of over 6.0% are achieved with a squaraine compound from co-deposited photovoltaic cells with a simple device structure, in which the efficiency is insensitive to blending ratios and thicknesses of photoactive layers. It demonstrates the huge potential of low molecular weight materials in photovoltaic cells via vacuum processes.