Strong optical response and light emission from a monolayer molecular crystal

Huijuan Zhao, Yingbo Zhao, Yinxuan Song, Ming Zhou, Wei Lv, Liu Tao, Yuzhang Feng, Biying Song, Yue Ma, Junqing Zhang, Jun Xiao, Ying Wang, Der Hsien Lien, Matin Amani, Hyungjin Kim, Xiaoqing Chen, Zhangting Wu, Zhenhua Ni, Peng Wang, Yi ShiHaibo Ma, Xiang Zhang, Jian Bin Xu, Alessandro Troisi, Ali Javey, Xinran Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Excitons in two-dimensional (2D) materials are tightly bound and exhibit rich physics. So far, the optical excitations in 2D semiconductors are dominated by Wannier-Mott excitons, but molecular systems can host Frenkel excitons (FE) with unique properties. Here, we report a strong optical response in a class of monolayer molecular J-aggregates. The exciton exhibits giant oscillator strength and absorption (over 30% for monolayer) at resonance, as well as photoluminescence quantum yield in the range of 60–100%. We observe evidence of superradiance (including increased oscillator strength, bathochromic shift, reduced linewidth and lifetime) at room-temperature and more progressively towards low temperature. These unique properties only exist in monolayer owing to the large unscreened dipole interactions and suppression of charge-transfer processes. Finally, we demonstrate light-emitting devices with the monolayer J-aggregate. The intrinsic device speed could be beyond 30 GHz, which is promising for next-generation ultrafast on-chip optical communications.

Original languageEnglish
Article number5589
JournalNature Communications
Volume10
Issue number1
DOIs
StatePublished - 1 Dec 2019

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