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Overcoming the electroluminescence efficiency limitations of perovskite light-emitting diodes
Science ( IF 44.7 ) Pub Date : 2015-12-03 , DOI: 10.1126/science.aad1818
Himchan Cho 1 , Su-Hun Jeong 1 , Min-Ho Park 1 , Young-Hoon Kim 1 , Christoph Wolf 1 , Chang-Lyoul Lee 2 , Jin Hyuck Heo 3 , Aditya Sadhanala 4 , NoSoung Myoung 2 , Seunghyup Yoo 5 , Sang Hyuk Im 3 , Richard H. Friend 4 , Tae-Woo Lee 1, 6
Affiliation  

Brighter perovskite LEDs Organic-inorganic hybrid perovskites such as methyl ammonium lead halides are attractive as low-cost light-emitting diode (LED) emitters. This is because, unlike many inorganic nanomaterials, they have very high color purity. Cho et al. made two modifications to address the main drawback of these materials, their low luminescent efficiency. They created nanograin materials lacking free metallic lead, which helped to confine excitons and avoid their quenching. The perovskite LEDs had a current efficiency similar to that of phosphorescent organic LEDs. Science, this issue p. 1222 Efficient organic-inorganic perovskite light-emitting diodes were made with nanograin crystals that lack metallic lead. Organic-inorganic hybrid perovskites are emerging low-cost emitters with very high color purity, but their low luminescent efficiency is a critical drawback. We boosted the current efficiency (CE) of perovskite light-emitting diodes with a simple bilayer structure to 42.9 candela per ampere, similar to the CE of phosphorescent organic light-emitting diodes, with two modifications: We prevented the formation of metallic lead (Pb) atoms that cause strong exciton quenching through a small increase in methylammonium bromide (MABr) molar proportion, and we spatially confined the exciton in uniform MAPbBr3 nanograins (average diameter = 99.7 nanometers) formed by a nanocrystal pinning process and concomitant reduction of exciton diffusion length to 67 nanometers. These changes caused substantial increases in steady-state photoluminescence intensity and efficiency of MAPbBr3 nanograin layers.

中文翻译:

克服钙钛矿发光二极管的电致发光效率限制

更亮的钙钛矿 LED 有机-无机杂化钙钛矿,如甲基铵卤化铅,作为低成本的发光二极管 (LED) 发射器很有吸引力。这是因为,与许多无机纳米材料不同,它们具有非常高的色纯度。Cho 等人。进行了两项修改以解决这些材料的主要缺点,即它们的低发光效率。他们创造了缺乏游离金属铅的纳米颗粒材料,这有助于限制激子并避免它们的淬火。钙钛矿 LED 具有与磷光有机 LED 相似的电流效率。科学,这个问题 p。1222 高效的有机-无机钙钛矿发光二极管由不含金属铅的纳米晶粒晶体制成。有机-无机杂化钙钛矿是新兴的低成本发光体,具有非常高的色纯度,但它们的低发光效率是一个严重的缺点。我们将具有简单双层结构的钙钛矿发光二极管的电流效率 (CE) 提高到每安培 42.9 坎德拉,类似于磷光有机发光二极管的 CE,并进行了两项修改:我们阻止了金属铅 (Pb ) 通过甲基溴化铵 (MABr) 摩尔比例的小幅增加引起强烈激子猝灭的原子,我们将激子空间限制在由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中,并伴随激子扩散长度的减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。我们将具有简单双层结构的钙钛矿发光二极管的电流效率 (CE) 提高到每安培 42.9 坎德拉,类似于磷光有机发光二极管的 CE,并进行了两项修改:我们阻止了金属铅 (Pb ) 通过甲基溴化铵 (MABr) 摩尔比例的小幅增加引起强烈激子猝灭的原子,我们将激子空间限制在由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中,并伴随激子扩散长度的减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。我们将具有简单双层结构的钙钛矿发光二极管的电流效率 (CE) 提高到每安培 42.9 坎德拉,类似于磷光有机发光二极管的 CE,并进行了两项修改:我们阻止了金属铅 (Pb ) 通过甲基溴化铵 (MABr) 摩尔比例的小幅增加引起强烈激子猝灭的原子,我们将激子空间限制在由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中,并伴随激子扩散长度的减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。类似于磷光有机发光二极管的 CE,有两个修改:我们通过小幅增加甲基溴化铵 (MABr) 摩尔比例来防止金属铅 (Pb) 原子的形成,从而导致强烈的激子猝灭,并且我们在空间上限制了由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中的激子,同时将激子扩散长度减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。类似于磷光有机发光二极管的 CE,有两个修改:我们通过小幅增加甲基溴化铵 (MABr) 摩尔比例来防止金属铅 (Pb) 原子的形成,从而导致强烈的激子猝灭,并且我们在空间上限制了由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中的激子,同时将激子扩散长度减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。我们将激子空间限制在由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中,同时将激子扩散长度减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。我们将激子空间限制在由纳米晶体钉扎过程形成的均匀 MAPbBr3 纳米颗粒(平均直径 = 99.7 纳米)中,同时将激子扩散长度减少到 67 纳米。这些变化导致 MAPbBr3 纳米晶粒层的稳态光致发光强度和效率大幅增加。
更新日期:2015-12-03
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