Colloidal quasi-2D Cs2AgBiBr6 double perovskite nanosheets: synthesis and application as high-performance photodetectors

TL;DR

This paper reports the synthesis of colloidal quasi-2D Cs2AgBiBr6 nanosheets and their application in high-performance, stable, lead-free photodetectors with impressive sensitivity and speed.

Contribution

It introduces a low-temperature colloidal synthesis method for quasi-2D Cs2AgBiBr6 nanosheets and demonstrates their effectiveness in fabricating high-performance, stable photodetectors.

Findings

Achieved nanosheets with lateral sizes up to 1.4 μm and thickness of a few nanometers.

Photodetectors showed high detectivity (1.15×10^12 Jones) and responsivity (121 mA/W).

Devices maintained performance after 80 days in ambient conditions.

Abstract

The search for non-toxic lead-free halide perovskites that can compete with the lead-based counterparts has led to the emergence of double perovskites as potential candidates. Among many options, Cs2AgBiBr6 stands out as one of the most suitable eco-friendly materials for numerous optoelectronic applications. In this study, quasi-2D Cs2AgBiBr6 nanosheets (NSs) were prepared via the low-temperature injection colloidal synthesis and used to fabricate high-performance photodetectors in a transport-layer-free architecture. The reaction temperature and ligands played vital roles in the structural purity, shape, and size of the synthesized Cs2AgBiBr6 NSs. The fabricated NSs disclosed lateral sizes of up to 1.4 um and are only a few nanometers thick. The high-performance photodetectors fabricated using the Cs2AgBiBr6 NSs yielded a high detectivity (D) of 1.15*10^12 Jones, responsivity (R) of 121 mA/W, a notable on/off ratio of 2.39*10^4, and a fast rise and decay time of 857 and 829 us, respectively. The device demonstrates remarkable stability. Basically, it sustains its entire photocurrent after storage in ambient conditions for 80 days. This work showcases a pathway for the colloidal synthesis of quasi-2D Cs2AgBiBr6 lead-free double perovskite NSs with suitable properties for high-performance photodetection and other optoelectronic applications.