Enhanced AgBiS2 Colloidal Quantum Dot Infrared Photodetector by Modifying with 2D MXene Nanoflakes

Abstract

Colloidal quantum dot (CQD) infrared (IR) photodetectors exhibit great application potential in the fields of optical communication, environmental monitoring, imaging, and wearable sensing. Specifically, AgBiS2 CQD IR photodetectors have garnered extensive attention because of their excellent photoelectric properties, solution-processability, as well as non-toxicity and environmental friendliness. However, the high trap density and relatively low carrier mobility of AgBiS2 CQDs have limited their development in high-performance IR photodetectors. Herein, a representative 2D transition carbide, Ti3C2Tx, is introduced into the AgBiS2 CQD films to develop enhanced IR photodetectors based on MXene/AgBiS2 hybrid films. By finely controlling of the MXene additive concentration, this combination possibly helps reduce trap state density in AgBiS2 films to suppress carrier nonradiative recombination and simultaneously constructs an efficient conductive pathway in AgBiS2 films to enhance the extraction of photo-generated carriers. Consequently, compared to the pristine AgBiS2 CQD devices, the MXene/AgBiS2 CQD-based infrared photodetector exhibits significant promotion in the responsivity, EQE, and estimated normalized detectivity under a broad band from 500 to 900 nm, demonstrating an alternative method for tailoring the performance of AgBiS2 CQD optoelectronic devices.