Band Structure Engineering of Interfacial Semiconductors Based on Atomically Thin Lead Iodide Crystals

  • Yan Sun
  • , Zishu Zhou
  • , Zhen Huang
  • , Jiangbin Wu
  • , Liujiang Zhou
  • , Yang Cheng
  • , Jinqiu Liu
  • , Chao Zhu
  • , Maotao Yu
  • , Peng Yu
  • , Wei Zhu
  • , Yue Liu
  • , Jian Zhou
  • , Bowen Liu
  • , Hongguang Xie
  • , Yi Cao
  • , Hai Li
  • , Xinran Wang
  • , Kaihui Liu
  • , Xiaoyong Wang
  • Jianpu Wang, Lin Wang, Wei Huang

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

To explore new constituents in two-dimensional (2D) materials and to combine their best in van der Waals heterostructures is in great demand as being a unique platform to discover new physical phenomena and to design novel functionalities in interface-based devices. Herein, PbI 2 crystals as thin as a few layers are synthesized, particularly through a facile low-temperature solution approach with crystals of large size, regular shape, different thicknesses, and high yields. As a prototypical demonstration of band engineering of PbI 2 -based interfacial semiconductors, PbI 2 crystals are assembled with several transition metal dichalcogenide monolayers. The photoluminescence of MoS 2 is enhanced in MoS 2 /PbI 2 stacks, while a dramatic photoluminescence quenching of WS 2 and WSe 2 is revealed in WS 2 /PbI 2 and WSe 2 /PbI 2 stacks. This is attributed to the effective heterojunction formation between PbI 2 and these monolayers; type I band alignment in MoS 2 /PbI 2 stacks, where fast-transferred charge carriers accumulate in MoS 2 with high emission efficiency, results in photoluminescence enhancement, and type II in WS 2 /PbI 2 and WSe 2 /PbI 2 stacks, with separated electrons and holes suitable for light harvesting, results in photoluminescence quenching. The results demonstrate that MoS 2 , WS 2 , and WSe 2 monolayers with similar electronic structures show completely distinct light–matter interactions when interfacing with PbI 2 , providing unprecedented capabilities to engineer the device performance of 2D heterostructures.

Original languageEnglish
Article number1806562
JournalAdvanced Materials
Volume31
Issue number17
DOIs
StatePublished - 25 Apr 2019

Keywords

  • 2D materials
  • band alignment
  • heterostructures
  • interlayer interactions
  • lead iodide

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