A Wide Bandgap Halide Perovskite Based Self-Powered Blue Photodetector with 84.9% of External Quantum Efficiency.

Yun, Yeonghun; Han, Gill Sang; Park, Gyu Na; Kim, Jihyun; Park, Jinhong; Vidyasagar, Devthade; Jung, Jina; Choi, Won Chang et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

A self-powered, color-filter-free blue photodetector (PD) based on halide perovskites is reported. A high external quantum efficiency (EQE) of 84.9%, which is the highest reported EQE in blue PDs, is achieved by engineering the A-site monovalent cations of wide-bandgap perovskites. The optimized composition of formamidinium (FA)/methylammonium (MA) increases the heat of formation, yielding a uniform and smooth film. The incorporation of Cs<sup>+</sup> ions into the FA/MA composition suppresses the trap density and increases charge-carrier mobility, yielding the highest average EQE of 77.4%, responsivity of 0.280 A W<sup>-1</sup> , and detectivity of 5.08 × 10<sup>12</sup> Jones under blue light. Furthermore, Cs<sup>+</sup> improves durability under repetitive operations and ambient atmosphere. The proposed device exhibits peak responsivity of 0.307 A W<sup>-1</sup> , which is higher than that of the commercial InGaN-based blue PD (0.289 A W<sup>-1</sup> ). This study will promote the development of next-generation image sensors with vertically stacked perovskite PDs.