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High-Efficiency Polycrystalline Perovskite Light-Emitting Diodes Based on Mixed Cations
ACS Nano ( IF 15.8 ) Pub Date : 2018-03-01 00:00:00 , DOI: 10.1021/acsnano.8b00409 Himchan Cho , Joo Sung Kim , Christoph Wolf 1 , Young-Hoon Kim , Hyung Joong Yun 2 , Su-Hun Jeong , Aditya Sadhanala 3 , Vijay Venugopalan 3 , Jin Woo Choi 4 , Chang-Lyoul Lee 4 , Richard H. Friend 3 , Tae-Woo Lee
ACS Nano ( IF 15.8 ) Pub Date : 2018-03-01 00:00:00 , DOI: 10.1021/acsnano.8b00409 Himchan Cho , Joo Sung Kim , Christoph Wolf 1 , Young-Hoon Kim , Hyung Joong Yun 2 , Su-Hun Jeong , Aditya Sadhanala 3 , Vijay Venugopalan 3 , Jin Woo Choi 4 , Chang-Lyoul Lee 4 , Richard H. Friend 3 , Tae-Woo Lee
Affiliation
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We have achieved high-efficiency polycrystalline perovskite light-emitting diodes (PeLEDs) based on formamidinium (FA) and cesium (Cs) mixed cations without quantum dot synthesis. Uniform single-phase FA1–xCsxPbBr3 polycrystalline films were fabricated by one-step formation with various FA:Cs molar proportions; then the influences of chemical composition on film morphology, crystal structure, photoluminescence (PL), and electroluminescence (EL) were systematically investigated. Incorporation of Cs+ cations in FAPbBr3 significantly reduced the average grain size (to 199 nm for FA:Cs = 90:10) and trap density; these changes consequently increased PL quantum efficiency (PLQE) and PL lifetime of FA1–xCsxPbBr3 films and current efficiency (CE) of PeLEDs. Further increase in Cs molar proportion from 10 mol % decreased crystallinity and purity, increased trap density, and correspondingly decreased PLQE, PL lifetime, and CE. Incorporation of Cs also increased photostability of FA1–xCsxPbBr3 films, possibly due to suppressed formation of light-induced metastable states. FA1–xCsxPbBr3 PeLEDs show the maximum CE = 14.5 cd A–1 at FA:Cs = 90:10 with very narrow EL spectral width (21–24 nm); this is the highest CE among FA-Cs-based PeLEDs reported to date. This work provides an understanding of the influences of Cs incorporation on the chemical, structural, and luminescent properties of FAPbBr3 polycrystalline films and a breakthrough to increase the efficiency of FA1–xCsxPbBr3 PeLEDs.
中文翻译：
基于混合阳离子的高效多晶钙钛矿发光二极管
我们已经实现了基于甲ami（FA）和铯（Cs）混合阳离子的高效多晶钙钛矿发光二极管（PeLEDs），而无需量子点合成。通过一步形成具有不同FA：Cs摩尔比的均匀单相FA 1 – x Cs x PbBr 3多晶膜；然后系统地研究了化学成分对薄膜形态，晶体结构，光致发光（PL）和电致发光（EL）的影响。FAPbBr 3中掺入Cs +阳离子可显着降低平均晶粒尺寸（FA：Cs = 90:10时，平均晶粒尺寸降至199 nm）和陷阱密度。这些变化因此提高了FA的PL量子效率（PLQE）和PL寿命1– x Cs x PbBr 3膜和PeLED的电流效率（CE）。Cs摩尔比从10mol％进一步增加，降低了结晶度和纯度，提高了陷阱密度，并相应降低了PLQE，PL寿命和CE。掺入铯还增加了FA 1- x Cs x PbBr 3薄膜的光稳定性，这可能是由于抑制了光诱导的亚稳态的形成。FA 1– x Cs x PbBr 3 PeLED显示最大CE = 14.5 cd A –1在FA：Cs = 90:10且EL光谱宽度非常窄（21–24 nm）时；这是迄今为止报道的基于FA-Cs的PeLED中最高的CE。这项工作提供了对Cs掺入对FAPbBr 3多晶膜的化学，结构和发光性质的影响的理解，以及对提高FA 1- x Cs x PbBr 3 PeLED效率的突破。
更新日期：2018-03-01
中文翻译：
基于混合阳离子的高效多晶钙钛矿发光二极管
我们已经实现了基于甲ami（FA）和铯（Cs）混合阳离子的高效多晶钙钛矿发光二极管（PeLEDs），而无需量子点合成。通过一步形成具有不同FA：Cs摩尔比的均匀单相FA 1 – x Cs x PbBr 3多晶膜；然后系统地研究了化学成分对薄膜形态，晶体结构，光致发光（PL）和电致发光（EL）的影响。FAPbBr 3中掺入Cs +阳离子可显着降低平均晶粒尺寸（FA：Cs = 90:10时，平均晶粒尺寸降至199 nm）和陷阱密度。这些变化因此提高了FA的PL量子效率（PLQE）和PL寿命1– x Cs x PbBr 3膜和PeLED的电流效率（CE）。Cs摩尔比从10mol％进一步增加，降低了结晶度和纯度，提高了陷阱密度，并相应降低了PLQE，PL寿命和CE。掺入铯还增加了FA 1- x Cs x PbBr 3薄膜的光稳定性，这可能是由于抑制了光诱导的亚稳态的形成。FA 1– x Cs x PbBr 3 PeLED显示最大CE = 14.5 cd A –1在FA：Cs = 90:10且EL光谱宽度非常窄（21–24 nm）时；这是迄今为止报道的基于FA-Cs的PeLED中最高的CE。这项工作提供了对Cs掺入对FAPbBr 3多晶膜的化学，结构和发光性质的影响的理解，以及对提高FA 1- x Cs x PbBr 3 PeLED效率的突破。
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