CsPbX3‐ITO (X = Cl, Br, I) Nano‐Heterojunctions: Voltage Tuned Positive to Negative Photoresponse. Issue 28 (9th June 2021)

• Record Type: Journal Article
• Authors: He, Qiqian; Chen, Gaoyu; Wang, Yongkai; Liu, Xiaoyu; Xu, Danting; Xu, Xiangxing; Liu, Ying; Bao, Jianchun; Wang, Xun
• Is Part Of: Small. Volume 17:Issue 28(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-09
• Subjects: indium tin oxide -- nano‐heterojunctions -- negative photoresponse -- perovskites -- positive photoresponse -- quantum dots; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202101403
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: All‐Inorganic perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) have attracted tremendous attention in the past few years for their appealing performance in optoelectronic applications. Major properties of CsPbX3 QDs include the positive photoconductivity (PPC) and the defect tolerance of the in‐band trap states. Here it is reported that when hybridizing CsPbX3 QDs with indium tin oxide (ITO) nanocrystals to form CsPbX3 ‐ITO nano‐heterojunctions (NHJs), a voltage tuned photoresponse—from PPC to negative photoconductivity (NPC) transform—is achieved in lateral drain‐source structured ITO/CsPbX3 ‐ITO‐NHJs/ITO devices. A model combining exciton, charge separation, transport, and most critical the voltage driven electron filling of the in‐band trap states with drain–source voltage ( V DS ) above a threshold, is proposed to understand this unusual PPC‐NPC transform mechanism, which is different from that of any known nanomaterial system. This finding exhibits potentials for developing devices such as photodetectors, optoelectronic switches, and memories. Abstract : A peculiar voltage tuned photoresponse—from positive photoconductivity (PPC) to negative photoconductivity (NPC) transform—is achieved in CsPbX3 (X = Cl, Br, I) quantum dots (QDs) based lateral drain–source structured ITO/CsPbX3 ‐ITO‐NHJs/ITO devices. The electron filling of the in‐band traps of CsPbX3 QDs above a voltage threshold is proposed to elucidate the PPC‐NPC transform mechanism.