Narrowband Green-Light-Selective Organic Photodiodes for Full-Color Imaging
Journal
OPT EXPRESS
Date
2019.08.22
Abstract
In this work, two newly synthesized p-type dipolar small molecules are reported for application to green-light-selective organic photodiodes (OPDs). The two molecules get a cyanine-like character with intense and sharp absorption in the green color by adjusting the strength of their donating and accepting parts, and by choosing a selenophene unit as a ？-linker. When combined to C60 as the n-type material in a bulk heterojunction (BHJ), the external quantum efficiency (EQE) reaches 70％ in a complete device composed of two transparent electrodes. In addition, in order to reduce the blue-color absorption induced by the use of C60, the electron donor:electron acceptor composition ratio is tuned in the BHJ. With this light manipulation approach, the blue EQE is minimized to 18％ after reducing the C60 concentration in the center part of the BHJ. Finally, a hybrid full-color image sensor is fabricated without additional filter by using the developed green OPD as the top-layer in a stacked device architecture.