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High Light Outcoupling Efficiency from Periodically Corrugated OLEDs
ACS Omega ( IF 3.7 ) Pub Date : 2021-03-23 , DOI: 10.1021/acsomega.1c00903 Yu Zhang 1 , Rana Biswas 1, 2
ACS Omega ( IF 3.7 ) Pub Date : 2021-03-23 , DOI: 10.1021/acsomega.1c00903 Yu Zhang 1 , Rana Biswas 1, 2
Affiliation
Organic light-emitting diodes (OLEDs) suffer from poor light outcoupling efficiency (ηout < 20%) due to large internal waveguiding in the high-index layers/substrate, and plasmonic losses at the metal cathode interface. A promising approach to enhance light outcoupling is to utilize internal periodic corrugations that can diffract waveguided and plasmonic modes back to the air cone. Although corrugations can strongly diffract trapped modes, the optimal geometry of corrugations and limits to ηout are not well-established. We develop a general rigorous scattering matrix theory for light emission from corrugated OLEDs, by solving Maxwell’s equations in Fourier space, incorporating the environment-induced modification of the optical emission rate (Purcell effect). We computationally obtain the spectrally emissive power inside and outside the OLED. We find conformally corrugated OLEDs, where all OLED interfaces are conformal with a photonic crystal substrate, having triangular lattice symmetry, exhibit high light outcoupling ηout ∼60–65%, and an enhancement factor exceeding 3 for optimal pitch values between 1 and 2.5 μm. Waveguided and surface plasmon modes are strongly diffracted to the air cone through first-order diffraction. ηout is insensitive to corrugation heights larger than 100 nm. There is a gradual roll-off in ηout for a larger pitch and sharper decreases for small pitch values. Plasmonic losses remain below 10% for all corrugation pitch values. Our predicted OLED designs provide a pathway for achieving very high light outcoupling over the full optical spectrum that can advance organic optoelectronic science and solid-state lighting.
中文翻译:
周期性波纹 OLED 的高光出耦合效率
有机发光二极管 (OLED) 由于高折射率层/衬底中的大内部波导以及金属阴极界面处的等离子体损耗,光出耦合效率差(η %3C 20%)。增强光出耦合的一种很有前途的方法是利用内部周期波纹,可以将波导和等离子体模式衍射回气锥。尽管波纹可以强烈衍射俘获模式,但波纹的最佳几何形状和η极限尚未完全确定。我们通过在傅里叶空间中求解麦克斯韦方程组,结合环境诱导的光发射率修改(Purcell 效应),为波纹 OLED 的光发射开发了一个通用的严格散射矩阵理论。我们通过计算获得 OLED 内部和外部的光谱发射功率。我们发现了保形波纹 OLED,其中所有 OLED 界面都与光子晶体衬底保形,具有三角形晶格对称性,表现出 ∼60-65%的高光外耦合η,对于在 1 到 2.5 μm 之间的最佳间距值,增强因子超过 3。波导和表面等离激元模式通过一阶衍射强烈衍射到空气锥。ηout 对大于 100 nm 的波纹高度不敏感。较大的音高会逐渐降低入η出,而小的音高值会急剧降低。所有波纹间距值的等离子体损耗保持在 10% 以下。我们预测的 OLED 设计为在整个光谱上实现非常高的光出耦合提供了一条途径,可以推进有机光电科学和固态照明。
更新日期:2021-04-06
中文翻译:
周期性波纹 OLED 的高光出耦合效率
有机发光二极管 (OLED) 由于高折射率层/衬底中的大内部波导以及金属阴极界面处的等离子体损耗,光出耦合效率差(η %3C 20%)。增强光出耦合的一种很有前途的方法是利用内部周期波纹,可以将波导和等离子体模式衍射回气锥。尽管波纹可以强烈衍射俘获模式,但波纹的最佳几何形状和η极限尚未完全确定。我们通过在傅里叶空间中求解麦克斯韦方程组,结合环境诱导的光发射率修改(Purcell 效应),为波纹 OLED 的光发射开发了一个通用的严格散射矩阵理论。我们通过计算获得 OLED 内部和外部的光谱发射功率。我们发现了保形波纹 OLED,其中所有 OLED 界面都与光子晶体衬底保形,具有三角形晶格对称性,表现出 ∼60-65%的高光外耦合η,对于在 1 到 2.5 μm 之间的最佳间距值,增强因子超过 3。波导和表面等离激元模式通过一阶衍射强烈衍射到空气锥。ηout 对大于 100 nm 的波纹高度不敏感。较大的音高会逐渐降低入η出,而小的音高值会急剧降低。所有波纹间距值的等离子体损耗保持在 10% 以下。我们预测的 OLED 设计为在整个光谱上实现非常高的光出耦合提供了一条途径,可以推进有机光电科学和固态照明。