Low Band Gap Polymer: Fullerene based Photodetector with Spectral Response from 350 nm to 850 nm

Abstract

We report fabrication and characterization of high performance wideband photodetector with inverted device structure based on low bandgap polymer (poly[[4, 8-bis [(2 Ethylhexyl) oxy] benzo[1, 2-b:4, S-b′]dithiophene-2, 6-diyl] [3-fluoro-2-[(2ethylhexyl) carbonyl] thieno [3, 4-b] thiophenediyl]] (PTB7)): fullerene ([6, 6]-phenyl C61 butyric acid methyl ester (PCBM)) bulk heterojunction. ZnO nanorods are used to serve dual functions one as an electron transport layer (ETL) second as an active layer. Herein, we successfully demonstrated polymer: fullerene composites-based photodetectors with a wide spectral response from 350 nm to 850 nm. The proposed photodetector at a low external bias of -0.5V exhibits a high value of responsivity greater than 1.23 A/W over the broad spectral range from 350 nm to 850 nm. © 2021 IEEE.