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 Shi; Haibo Ma; Xiang Zhang; Jian-Bin Xu; Alessandro Troisi; Ali Javey; Xinran Wang

doi:10.1038/s41467-019-13581-9

Strong optical response and light emission from a monolayer molecular crystal

Nat Commun. 2019 Dec 6;10(1):5589. doi: 10.1038/s41467-019-13581-9.

Authors

Huijuan Zhao¹, Yingbo Zhao², Yinxuan Song³, Ming Zhou⁴, Wei Lv¹, Liu Tao¹, Yuzhang Feng⁵, Biying Song⁵, Yue Ma¹, Junqing Zhang¹, Jun Xiao⁶, Ying Wang⁶, Der-Hsien Lien², Matin Amani², Hyungjin Kim², Xiaoqing Chen^{1

7}, Zhangting Wu⁸, Zhenhua Ni⁸, Peng Wang⁵, Yi Shi¹, Haibo Ma⁹, Xiang Zhang⁶, Jian-Bin Xu¹⁰, Alessandro Troisi¹¹, Ali Javey¹², Xinran Wang¹³

Affiliations

¹ National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
² Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
³ Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
⁴ Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Madison, 53705, USA.
⁵ National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
⁶ NSF Nanoscale Science and Engineering Center (NSEC), University of California, Berkeley, CA, 94720, USA.
⁷ School of Microelectronics, Xidian University, Xian, 710071, China.
⁸ Department of Physics, Southeast University, Nanjing, 211189, China.
⁹ Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China. haibo@nju.edu.cn.
¹⁰ Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, 999077, China.
¹¹ Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, U.K.
¹² Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. ajavey@berkeley.edu.
¹³ National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China. xrwang@nju.edu.cn.

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.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't