In Situ Surface Modification Enables High Stability and Optoelectrical Performance for a Self‐powered Photodetector

Abstract

Perovskite single crystals (SCs) have gained significant interest in various applications owing to their superior optoelectrical and physical characteristics as compared to polycrystalline films. However, a considerable portion of incident light is typically reflected at the surface of perovskite SCs, leading to insufficient light absorption within the crystal bulk, ultimately resulting in reduced performance of SC‐based photodetectors. In the present work, an inverted pyramid‐shaped structure is in situ introduced on the surface of an MAPbBr3 SC during the crystal growth process, which can reduce light reflection in the surface region and enhance light absorption of the SC. Additionally, the hydrophobic small molecule copper (II) phthalocyanine (CuPc) is thermally evaporated onto the SC, forming a CuPc/MAPbBr3 heterojunction for the first time. The CuPc/pyramid‐shaped MAPbBr3 heterojunction‐based photodetector exhibits self‐powered characteristics and superior optoelectrical performance, achieving a photocurrent of greater than 10−5 A (10−7 A), a responsiveness of 257 mA W−1 (8.84 mA W−1), and a detection rate of 2.98 × 1012 Jones (1.02 × 1011 Jones) at −2 V (0 V) bias. Simultaneously, the device demonstrates excellent long‐term stability under high humidity conditions, retaining 90.5% of its initial photocurrent even after 60 days in a 60–80% humidity environment.

High-performance self-powered ultraviolet photodetector based on a ZnO/CuPc inorganic/organic heterojunction

“…Moreover, the absorption spectrum of the CuPc lm (Fig. 2(d)) shows two obvious absorption edges located at ∼622 nm and 694 nm, which are called Q-bands, originating from the electron conversion of p-p 26,27 However, the hybrid lm formed by the combination of ZnO and introduced CuPc not only improves the absorption but also broadens the range of absorption spectra. This suggests that the hybrid lm may be applicable in the manufacturing of broadband optoelectronic devices.…”