Organic position sensitive photodetectors based on lateral donor-acceptor concentration gradients

We report on an organic photodiode configuration based on a donor/acceptor bilayer with opposed complementary thickness gradients. We rely on the strong dependence of the optical field on thickness to achieve spatially dependent spectral responses, a proof-of-concept for position sensitive detection. Ratiometric photocurrent values at two wavelengths allow for position determination independently of the light intensity with a spatial resolution below 600 mu m. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3631731]