Silicon-Rivalling Large-Area Flexible Broadband Organic Photodetectors.

Abstract

Organic photodetectors (OPDs) have demonstrated significant advantages as a promising next-generation photodetection technology, especially for application in flexible and curved image sensing. However, there is still a big gap in device performance between OPDs and commercial silicon photodiodes, which hinders their practical application. Herein, using a novel near-infrared electron acceptor featuring acceptor-donor-acceptor molecular skeleton and electron-withdrawing cyano-substituted terminal groups, the study reports an OPD that can fully compete with the commercial silicon photodiodes. Benefiting from the strong electron push-pull effect and large molecular dipole moment, the OPD exhibits a broad detection range from 300 to 1100 nm and a peak external quantum efficiency of 70% at 940 nm. Moreover, owing to the reduced energetic disorder and trap density, the OPD exhibits a picoampere-level dark current density (1.30 × 10^-10 A cm^-2) at -0.1 V bias. Such high responsivity and low dark current density endow the OPD with a detectivity surpassing 10¹³ Jones across the whole spectral range. More importantly, this superior photodetection performance can be maintained in large-area flexible device (80 mm²). These results demonstrate the huge potential of OPDs in addressing the limitations of silicon photodiodes for application in flexible and wearable electronics.