High efficiency polymer photodiodes

Organic polymer photodiodes have been fabricated using different device designs, and by the use of blends between derivatives of poly(thiophene) and poly(phenylene vinylene), a broad wavelength response is accomplished. For single layer devices, an external quantum yield of 4.5% is achieved under short-circuit conditions, increasing to 28% at 2V negative bias. Even better results are found for double layer devices, having a spectral response covering the range from 350 nm to 750 nm, and exhibiting 28% external quantum yield at short circuit and reaching almost 60% at -2V bias.