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Band Structure Engineering of Interfacial Semiconductors Based on Atomically Thin Lead Iodide Crystals
Author(s) -
Sun Yan,
Zhou Zishu,
Huang Zhen,
Wu Jiangbin,
Zhou Liujiang,
Cheng Yang,
Liu Jinqiu,
Zhu Chao,
Yu Maotao,
Yu Peng,
Zhu Wei,
Liu Yue,
Zhou Jian,
Liu Bowen,
Xie Hongguang,
Cao Yi,
Li Hai,
Wang Xinran,
Liu Kaihui,
Wang Xiaoyong,
Wang Jianpu,
Wang Lin,
Huang Wei
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201806562
Subject(s) - photoluminescence , materials science , heterojunction , monolayer , semiconductor , quenching (fluorescence) , optoelectronics , nanotechnology , thin film , fluorescence , optics , physics
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.