Regulating the phase distribution of quasi-2D perovskites using a three-dimensional cyclic molecule toward improved light-emitting performance

Chiung-Han Chen; Chiao-Hsin Hsu; I-Chih Ni; Bi-Hsuan Lin; Chih-I Wu; Chi-Ching Kuo; Chu-Chen Chueh

doi:10.1039/d2nr04735g

Regulating the phase distribution of quasi-2D perovskites using a three-dimensional cyclic molecule toward improved light-emitting performance

Nanoscale. 2022 Dec 1;14(46):17409-17417. doi: 10.1039/d2nr04735g.

Authors

Chiung-Han Chen^{1

2}, Chiao-Hsin Hsu³, I-Chih Ni⁴, Bi-Hsuan Lin⁵, Chih-I Wu⁴, Chi-Ching Kuo³, Chu-Chen Chueh^{1

2}

Affiliations

¹ Department of Chemical Engineering, National Taiwan, University, Taipei 10617, Taiwan. cchueh@ntu.edu.tw.
² Advanced Research Center for Green Materials Science and Technology, National Taiwan University, Taipei 10617, Taiwan.
³ Institute of Organic and Polymeric Material, National Taipei University of Technology, Taipei 10617, Taiwan. kuocc@mail.ntut.edu.tw.
⁴ Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.
⁵ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.

PMID: 36383153
DOI: 10.1039/d2nr04735g

Abstract

In this study, a molecule with a three-dimensional (3D) cyclic structure, a cryptand, is demonstrated as an effective additive for the quasi-two-dimensional (quasi-2D) PEA₂Cs_n-1Pb_nBr_3n+1 (n = 3, herein) to improve its light-emitting performance. The cryptand can effectively regulate the phase distribution of the quasi-2D perovskite through its intense interaction with PbBr₂, benefitting from its cage-like structure that can better capture the Pb²⁺ ions. Due to the inhibited growth of the low-n phases, a much-concentrated phase distribution is achieved for the cryptand-containing films. Moreover, its constituent O/N atoms can passivate the uncoordinated Pb²⁺ ions to improve the film quality. Such a synergistic effect thereby facilitates the charge/energy transfer among the multiple phases and reduces the non-radiative recombination. As a result, the quasi-2D perovskite light-emitting diode (PeLED) with the optimized cryptand doping ratio is shown to deliver the highest luminance (L_max) of 15 532 cd m^-2 with a highest external quantum efficiency (EQE) of 4.02%. Compared to the pristine device, L_max is enhanced by ∼5 times and EQE is enhanced by ∼10 times.