Improved optical-to-electrical conversion efficiency by doping silole derivative with low ionization potential

In this paper, we investigated photoconductive characteristics of blue-sensitive organic photoconductive devices with different silole derivatives. A most important finding is that an external quantum efficiency (EQE) increased with decreasing ionization potential of silole derivative. The significant improved EQE can be explained by the dislocation efficiency of photogenerated carriers in the organic layer, which is estimated from the photoluminescence (PL) quantum yield. A maximum EQE of 52% at -26 MV m-1 was obtained by optimizing the molecular structure and the concentration of silole derivative. This value is the highest EQE for the reported solution-processed blue-sensitive organic photoconductive device. Another interesting result is that the signal-to-noise ratio was drastically improved by doping silole derivative. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)