Thickness-dependent photoresponse of P3HT:PCBM organic photodiode fabricated by drop-casting method

In this article, P3HT:PCBM organic photodetectors with micrometer level thickness active layer are fabricated by drop casting method. It is found that while the dark current of these detectors are all ~10 nA cm ^-2 , the photoresponse of these OPD decreases with thickness. When the active layer thickness is ~2 μm, a responsivity as high as 0.86 A/W is achieved when biased at -3V, resulting a directivity up to 10 ¹³ Jones.