Jeon Sohee, Zhao Lianfeng, Jung Young-Jin, Kim Ji Whan, Kim Sei-Yong, Kang Hyeokjung, Jeong Jun-Ho, Rand Barry P, Lee Jeong-Hwan
Nano-Convergence Mechanical Research Division, Korea Institute of Machinery and Materials (KIMM), Yuseong-gu, Daejeon, 34103, Republic of Korea.
Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA.
Small. 2019 Feb;15(8):e1900135. doi: 10.1002/smll.201900135. Epub 2019 Jan 30.
Organic-inorganic hybrid perovskite light-emitting diodes (PeLEDs) are promising for next-generation optoelectronic devices due to their potential to achieve high color purity, efficiency, and brightness. Although the external quantum efficiency (EQE) of PeLEDs has recently surpassed 20%, various strategies are being pursued to increase EQE further and reduce the EQE gap compared to other LED technologies. A key point to further boost EQE of PeLEDs is linked to the high refractive index of the perovskite emissive layer, leading to optical losses of more than 70% of emitted photons. Here, it is demonstrated that a randomly distributed nanohole array with high-index contrast can effectively enhance outcoupling efficiency in PeLEDs. Based on a comprehensive optical analysis on the perovskite thin film and outcoupling structure, it is confirmed that the nanohole array effectively distributes light into the substrate for improved outcoupling, allowing for 1.64 times higher light extraction. As a result, highly efficient red/near-infrared PeLEDs with a peak EQE of 14.6% are demonstrated.
有机-无机杂化钙钛矿发光二极管（PeLEDs）因其具有实现高色纯度、高效率和高亮度的潜力，在下一代光电器件领域颇具前景。尽管PeLEDs的外量子效率（EQE）最近已超过20%，但人们仍在探索各种策略以进一步提高EQE，并缩小与其他LED技术相比的EQE差距。进一步提高PeLEDs的EQE的一个关键点与钙钛矿发光层的高折射率有关，这导致超过70%的发射光子出现光学损失。在此，证明了具有高折射率对比度的随机分布纳米孔阵列可有效提高PeLEDs的光出射效率。基于对钙钛矿薄膜和光出射结构的全面光学分析，证实纳米孔阵列可有效地将光分布到衬底中以改善光出射，使光提取提高1.64倍。结果，展示了峰值EQE为14.6%的高效红色/近红外PeLEDs。
