Spectrally selected photodiodes for colorimetric application

We demonstrate that it is possible to fine-tune the photocurrent action spectrum of an organic photodiode, based onto a prototype semiconducting polymer, simply varying the active layer thickness and properly exploiting the filter effect of the optical absorption. The theory adopted to model the experimental data represents a useful tool to predict with accuracy the position and the spectral shape of the photovoltaic current. Based on this result, we apply our method in the colorimetric field, where a simple way to tune the spectral response of the detector unit is highly desired: we realize an organic color sensor device without any optical filtering. (C) 2009 Elsevier B.V. All rights reserved.