Printing and In Situ Assembly of CdSe/CdS Nanoplatelets as Uniform Films with Unity In-Plane Transition Dipole Moment

Peng Bai; An Hu; Yang Liu; Yizheng Jin; Yunan Gao

doi:10.1021/acs.jpclett.0c00748

Printing and In Situ Assembly of CdSe/CdS Nanoplatelets as Uniform Films with Unity In-Plane Transition Dipole Moment

J Phys Chem Lett. 2020 Jun 4;11(11):4524-4529. doi: 10.1021/acs.jpclett.0c00748. Epub 2020 May 27.

Authors

Peng Bai¹, An Hu¹, Yang Liu², Yizheng Jin³, Yunan Gao^{1

4

5}

Affiliations

¹ State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
² Centre for Chemistry of High-Performance & Novel Materials, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
³ Centre for Chemistry of High-Performance & Novel Materials, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
⁴ Frontiers Science Center for Nano-optoelectronics, Beijing 100871, China.
⁵ Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China.

PMID: 32432888
DOI: 10.1021/acs.jpclett.0c00748

Abstract

Distribution of the transition dipole moments (TDMs) of light emitters can intrinsically affect the light out-coupling efficiency of planar light-emitting diodes (LEDs). Lacking the control of TDM distribution has limited the efficiency of nanocrystal-based LEDs to 20%. Here, we present a method that deposits uniform nanocrystal films with unity in-plane TDM distribution. Combining an inkjet printing technique and colloidal nanocrystal self-assembly, we achieved direct printing and in situ assembly of colloidal CdSe/CdS nanoplatelets to all orient "face-down" on various substrates. With motorized translation stages, pattern printing is realized, which demonstrates the potential for integration in industrial-scale fabrication. The method is applied to achieve uniform nanoplatelet films with unity in-plane TDM distribution on zinc-oxide films, a commonly used electron-transport layer. Thus, our work paves the way to break the light out-coupling efficiency limitation of 20% in state-of-the-art nanocrystal-based LEDs, which exclusively possess an isotropic TDM distribution.