Chen, Chiung HanChiung HanChenHsu, Chiao HsinChiao HsinHsuNi, I. ChihI. ChihNiLin, Bi HsuanBi HsuanLinCHIH-I WUKuo, Chi ChingChi ChingKuoCHU-CHEN CHUEH2023-05-292023-05-292022-11-0720403364https://scholars.lib.ntu.edu.tw/handle/123456789/631486In 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) PEA2Csn−1PbnBr3n+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 (Lmax) of 15 532 cd m−2 with a highest external quantum efficiency (EQE) of 4.02%. Compared to the pristine device, Lmax is enhanced by ∼5 times and EQE is enhanced by ∼10 times.en[SDGs]SDG7journal article10.1039/d2nr04735g363831532-s2.0-85142507965WOS:000885654700001https://api.elsevier.com/content/abstract/scopus_id/85142507965