Perseverance of direct bandgap in multilayer 2D PbI 2 under an experimental strain up to 7.69%

Lena Du, Cong Wang, Wenqi Xiong, Shuai Zhang, Congxin Xia, Zhongming Wei, Jingbo Li, Sefaattin Tongay, Fengyou Yang, Xinzheng Zhang, Xinfeng Liu, Qian Liu

Research output: Contribution to journalArticle

6 Scopus citations


The two-dimensional (2D) materials are naturally suitable for various flexible 2D optoelectronic devices, in which the direct band gap perseverance is crucial because the flexibility deformations often cause a bandgap transition and thus break performance of the devices. Most of 2D transition metal dichalcogenides (TMDs) materials such as monolayer MoS 2 , WS 2 and MoSe 2 have been thought to be not suitable for flexible optoelectronic devices due to their direct-to-indirect bandgap transition even under a small strain (∼1%-2%) for any flexibility deformations. So far, only 2D phosphorene has been theoretically predicted to be able to keep direct bandgap property under a large strain. Here we report a 2D material lead iodide (PbI 2 ) mutilayer with a direct band gap and find by photoluminescence (PL) measurements that it maintains a direct bandgap nature under a large experimental strain up to 7.69%. Theoretical simulations support and explain well our experimental results.

Original languageEnglish (US)
Article number025014
Journal2D Materials
Issue number2
StatePublished - Feb 8 2019

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Du, L., Wang, C., Xiong, W., Zhang, S., Xia, C., Wei, Z., Li, J., Tongay, S., Yang, F., Zhang, X., Liu, X., & Liu, Q. (2019). Perseverance of direct bandgap in multilayer 2D PbI 2 under an experimental strain up to 7.69% 2D Materials, 6(2), [025014].