Photomultiplication Type Organic Photodetectors with Broadband and Narrowband Response Ability

Abstract

AbstractIt is a great challenge to achieve highly sensitive organic photodetectors (OPDs) with broadband and narrowband response ability. The OPDs with an extraordinary structure of ITO/PFN‐OX/P3HT:PTB7‐Th:PC61BM (100‐x:x:1, wt/wt/wt)/Al are elaborately fabricated, exhibiting tunable spectral response dependent on the bias polarity. The optimized ternary OPDs with 3 µm P3HT:PTB7‐Th:PC61BM (40:60:1) as active layers exhibit broadband spectral response from 350 to 800 nm under forward bias and narrowband spectral response from 750 to 850 nm with a full width half maximum (FWHM) of ≈40 nm under reverse bias. In particular, the FWHM of narrowband response windows can be kept well under different reverse biases. Moreover, the optimized ternary OPDs also exhibit photomultiplication (PM) phenomenon under forward and reverse bias, resulting from the interfacial trap‐assisted hole tunneling injection from external circuit. This should be the first demonstration of PM type OPDs with broadband and narrowband response ability, which would possess wide potential applications, especially in integrated optoelectronic products.