Nanocrystalline titanium dioxide-dispersed semiconducting polymer photodetectors

Abstract

Photodetection properties of nanocrystalline titanium dioxide, TiO₂, dispersed in poly-2-methoxy-5-(2'-ethyl-hexoxy)-1,4 paraphenylenevinylene MEHPPV are studied. Responsivity as high as 50 mA/W is observed in the single− layered composite device. The spectral response is sensitive to the magnitude of the bias in the low-voltage range and the crossover from a symbatic to antibatic response is closely followed. At higher reverse bias, the response is relatively uniform throughout the entire spectral range. Differences in the switching response in the forward bias and reverse bias are observed with a pronounced effect of the persistence photocurrent in the forward bias.