Space‐Confined Growth of Individual Wide Bandgap Single Crystal CsPbCl3 Microplatelet for Near‐Ultraviolet Photodetection

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 15; no. 39; pp. e1902618 - n/a
• Main Authors: Gui, Pengbin, Zhou, Hai, Yao, Fang, Song, Zehao, Li, Borui, Fang, Guojia
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.09.2019
• Subjects: Artificial intelligence; CsPbCl3 single crystal microplatelets; Dark current; Energy gap; low temperature growth; Machine vision; Nanotechnology; near‐ultraviolet photodetectors; Perovskites; Single crystals; Thermal stability; Ultraviolet detectors
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201902618

Perovskite photodetectors (PDs) with tunable detection wavelength have attracted extensive attention due to the potential application in the field of imaging, machine vision, and artificial intelligence. Most of the perovskite PDs focus on I‐ or Br‐based materials due to their easy preparation techniques. However, their main photodetection capacity is situated in the visible region because of their narrower bandgap. Cl‐based wide bandgap perovskites, such as CsPbCl3, are scarcely reported because of the bad film quality of the spin‐coated Cl‐based perovskite, due to the poor solubility of the precursor. Therefore, ultraviolet detection using high‐quality full inorganic perovskite films, especially with high thermal stability of materials and devices, is still a big challenge. In this work, high‐quality single crystal CsPbCl3 microplatelets (MPs) synthesized by a simple space‐confined growth method at low temperature for near‐ultraviolet (NUV) PDs are reported. The single CsPbCl3 MP PDs demonstrate a decent response to NUV light with a high on/off ratio of 5.6 × 103 and a responsivity of 0.45 A W−1 at 5 V. In addition, the dark current is as low as pA level, leading to detectivity up to 1011 Jones. Moreover, PDs possess good stability and repeatability. A simple space‐confined growth method is introduced to synthesize high‐quality all‐inorganic wide bandgap single crystal CsPbCl3 microplatelets (MPs) at low temperature. This method overcomes the poor solubility of the precursor and obtains high‐crystallinity CsPbCl3 MPs. The as‐synthesized individual CsPbCl3 MP is introduced into a photodetector with high near‐ultraviolet photodetection performance and excellent high‐temperature thermal stability.