High-Sensitive Organic Quasi-tandem Narrowband Photodetector with Enhanced Spectral Selectivity

Abstract

Narrowband photodetectors (NPDs) with spectral selectivity capabilities have emerged as crucial components in diverse applications, including optical communications, surveillance systems, machine vision, and biomedical imaging. Here, we propose an all-organic quasi-tandem narrowband photodetector (QT-NPDs) comprising a PM6/ PEDOT:PSS/ PM6:IT-4F multi-stack quasi-tandem architecture. The PEDOT:PSS is strategically introduced as an intermediate connecting layer between the PM6 layer and the PM6:IT-4F heterojunction, effectively preventing mutual dissolution between these two films. Through manipulating the dissociation of Frenkel excitons in the front PM6 layer, we successfully suppress the light response induced by short wavelength corresponding to the PM6 absorption wavelength band. Further improvements in device performance are achieved by optimizing film preparation processes, resulting in increased light transmittance and absorption efficiency within the response range, along with enhanced charge carrier transport characteristics. These optimizations lead to an external quantum efficiency of 71% at a peak of 730 nm for the QT-NPDs, accompanied by a high specific detectivity of 6.99×1013 Jones. Our work represents the first innovative exploration of all-organic quasi-tandem narrowband detectors, paving the way for enriching both the fundamental theory and key implementation strategies of narrowband detectors.