Lead‐Free Perovskite Photodetectors: Progress, Challenges, and Opportunities

Abstract

State‐of‐the‐art photodetectors which apply hybrid perovskite materials have emerged as powerful candidates for next‐generation light sensing. Among them, lead‐based ones are the most popular beyond doubt on account of their unique and superior optoelectronic properties. Nevertheless, trade‐off toward commercialization exists between nontoxicity and high performance, with the poor stability of lead‐based perovskites, indicating that it is indispensable to substitute lead with nontoxic element meanwhile bringing about a comparable figure of merit of photodetectors and relatively long‐term stability. Herein, recent advances in lead‐free perovskite photodetectors are reviewed, analyzing the principle while designing new materials and highlighting some remarkable progress, which are comparable, even superior, to lead‐based photodetectors. Furthermore, their potential strategy in optical communication, image sensing, narrowband photodetection, etc., is examined and a perspective on developing new materials and photodetectors with superior properties for more practical applications is provided.

Highly Sensitive Ultraviolet and Visible Wavelength Sensor Composed of Two Identical Perovskite Nanofilm Photodetectors

“…Perovskite materials have demonstrated great potential in various optoelectronic applications due to their convenient solution processability, outstanding optical absorption capability, and tunable optoelectronic properties. [1][2][3][4][5] For example, to the conventional sensor employing optical filters. [27] Li and coworkers have synthesized an in situ formed gradient perovskite film with variable absorption edge from 450 to 780 nm, through controlling the heating temperature.…”

Photodetectors with High Responsivity by Thickness Tunable Mixed Halide Perovskite Nanosheets

“…The spectral responsivity and detectivity curves of the NS devices show a distinct region of applicability (Figure S23). − While Br 3 NS devices have a limited spectral range between 300 and 450 nm, the Br 1.5 I 1.5 and I 3 NS devices have broadband responses from 300 to 550 nm and 300 to 650 nm, respectively. The enhanced responsivity and detectivity of Br 1.5 I 1.5 NS-SCL devices is commensurate with its spectral response in a broad wavelength range.…”

Recent Progress on Perovskite Photodetectors for Narrowband Detection

“…Although lead-based halide perovskites have relatively good optoelectronic properties, their instability and toxicity of lead halide have hindered their commercialization on a large scale. [34,35,102,103] Therefore, lead-free perovskite materials gradually appear in the public eye. In the field of narrowband detection, we also find that there have been more literature reports on narrowband detection based on lead-free perovskites.…”

“…For example, with the replacement of A-site by large organic molecules (e.g., CH 3 (CH 2 ) 3 NH 3 þ , C 6 H 5 (CH 2 ) 2 NH 3 þ (abbreviate as BA þ , PEA þ )), the original 3D structure is disrupted to form a layered 2D structure; [32,33] the M-site can also be replaced by nondivalent elements Sn and Sb, constituting a lead-free halide perovskite variant. [34,35] The advantages of perovskites for making narrowband photodetectors stem first and foremost from its easily adjustable bandgap and excellent photoconversion capabilities. [27,36,37] The absorption spectral range can be easily adjusted by composition conversion engineering, and a range of perovskites that respond to different spectral ranges can be easily obtained.…”