Bright light-emitting diodes based on organometal halide perovskite
Bright light-emitting diodes based on organometal halide perovskite
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DOI：
10.1038/nnano.2014.149
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发表时间：
2014-09-01
影响因子：
38.3
通讯作者：
Friend, Richard H.
中科院分区：
文献类型：
--
作者：
Tan, Zhi-Kuang;Moghaddam, Reza Saberi;Friend, Richard H.
在过去的二十年中，基于直接带隙半导体的固态发光器件已经被用作节能照明源。然而，这些器件的制造通常依赖于昂贵的高温和高真空工艺，使得它们在大面积显示器中的使用不经济（1，2）。在这里，我们报告的高亮度发光二极管的基础上，解决方案处理的有机金属卤化物钙钛矿。我们证明了在近红外，绿色和红色的电致发光，通过调整钙钛矿中的卤化物组合物。在我们的红外设备中，CH 3 NH3 PbI 3-xClx钙钛矿发射体的15 nm薄层夹在较大带隙的二氧化钛（TiO 2）和聚（9，9 '-二辛基芴）（F8）层之间，有效地将电子和空穴限制在钙钛矿层中用于辐射复合。在电流密度为363 mA cm ~（-2）时，红外辐射率为13.2 W sr ~（-1）m ~（-2），最高外量子效率和内量子效率分别为0.76%和3.4%。在我们的绿色发光器件中，我们采用ITO/PEDOT：PSS/CH_3 NH_3 PbBr_3/F_8/Ca/Ag结构，在123 mA cm ~（-2）的电流密度下获得了364 cd·m ~（-2）的亮度，外量子效率和内量子效率分别为0.1%和0.4%。我们表明，使用光致发光的研究，辐射双分子复合占主导地位，在较高的激发密度。因此，钙钛矿发光二极管的量子效率在更高的电流密度下增加。这种有效的钙钛矿电致发光的演示为将这种独特的材料开发成高效且颜色可调的光发射器提供了空间，用于低成本显示，照明和光通信应用。
Solid-state light-emitting devices based on direct-bandgap semiconductors have, over the past two decades, been utilized as energy-efficient sources of lighting. However, fabrication of these devices typically relies on expensive high-temperature and high-vacuum processes, rendering them uneconomical for use in large-area displays(1,2). Here, we report high-brightness light-emitting diodes based on solution-processed organometal halide perovskites. We demonstrate electroluminescence in the near-infrared, green and red by tuning the halide compositions in the perovskite. In our infrared device, a thin 15 nm layer of CH3NH3PbI3-xClx perovskite emitter is sandwiched between larger-bandgap titanium dioxide (TiO2) and poly(9,9'-dioctyl-fluorene) (F8) layers, effectively confining electrons and holes in the perovskite layer for radiative recombination. We report an infrared radiance of 13.2 W sr(-1) m(-2) at a current density of 363 mA cm(-2), with highest external and internal quantum efficiencies of 0.76% and 3.4%, respectively. In our green light-emitting device with an ITO/PEDOT: PSS/CH3NH3PbBr3/F8/Ca/Ag structure, we achieved a luminance of 364 cd m(-2) at a current density of 123 mA cm(-2), giving external and internal quantum efficiencies of 0.1% and 0.4%, respectively. We show, using photoluminescence studies, that radiative bimolecular recombination is dominant at higher excitation densities. Hence, the quantum efficiencies of the perovskite light-emitting diodes increase at higher current densities. This demonstration of effective perovskite electroluminescence offers scope for developing this unique class of materials into efficient and colour-tunable light emitters for low-cost display, lighting and optical communication applications.