Tunable excitonic properties in two-dimensional heterostructures based on solution-processed PbI2 flakes

Zhen Huang, Yan Sun, Zhe Zhang, Zishu Zhou, Bowen Liu, Jingxian Zhong, Wei Zhang, Gang Ouyang, Junran Zhang, Lin Wang, Wei Huang

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

We investigate the manifestations of band structure engineering in few-layer PbI2-based heterostructures by probing their tunable optical properties. First, we have successfully prepared atomically thin flakes from PbI2 solution by two distinct approaches. A drop-casting of PbI2 solution onto various substrates followed by a simple heating process yields abundant flakes with different thickness and regular shape. Mechanical exfoliation of PbI2 bulk crystals, obtained from a low-temperature recrystallization process of PbI2 solution, also gives ultrathin PbI2 flakes of high quality. Moreover, these PbI2 flakes are employed to construct various van de Waals heterostructures. A significant enhancement of photoluminescence in MoSe2 interfaced with PbI2 was observed at different laser excitation intensity, due to the forming of type-I band alignment. Type-I band alignment can also be investigated in MoS2/PbI2 heterostructure, while type-II band alignment is built-in WSe2/PbI2 heterostructure. These results demonstrate that the strong interfacial coupling between PbI2 and other two-dimensional semiconductors can modulate their band alignment, and as a result, the exciton properties noticeably, which provides new insights of building a designer heterostructure device at the atomic level.

Original languageEnglish
Pages (from-to)10656-10667
Number of pages12
JournalJournal of Materials Science
Volume55
Issue number24
DOIs
StatePublished - 1 Aug 2020

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