1. Enhancing the Performance of Quasi-2D Perovskite Light-Emitting Diodes Using Natural Cyclic Molecules with Distinct Phase Regulation Behaviors.
- Author
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Chen CH, Kuo YH, Lin YK, Ni IC, Lin BH, Wu CI, Yip HL, Kuo CC, and Chueh CC
- Abstract
In this study, two natural small molecules, α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), are used as additives to improve the performance of quasi-2D PEA
2 Csn -1 Pbn Br3 n +1 ( n = 3, herein) PeLEDs. Both of them are shown to efficiently passivate the quasi-2D perovskite films to afford improved film quality and morphology, but they exhibit distinct phase regulation behaviors possibly due to their different pore sizes. It reveals that α-CD effectively suppresses the formation of the low- n phases ( n ≤ 2), while β-CD better regulates the phase with a medium- n value ( n = 3). Because of effectively suppressing the formation of low- n phases, the CD-assisted quasi-2D perovskite films possess facilitated exciton energy transfer and reduced nonradiative recombination. Consequently, the optimized α-CD-derived PeLED shows the highest luminance ( Lmax ) of 37,825 cd/m2 with an external quantum efficiency (EQE) of 3.81%, while the β-CD-derived PeLED delivers a lower Lmax of 24,793 cd/m2 with an EQE of 3.09%. Compared to the pristine device, Lmax is enhanced by 6.3 and 3.8 times for α-CD- and β-CD-based PeLEDs, respectively, and EQE is enhanced by ∼4.8 times for both devices; besides, both CD-assisted devices also exhibit improved color purity and a lower bias dependency of electroluminescent intensity.- Published
- 2022
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