Photonics design theory enhancing light extraction efficiency in quantum dot light emitting diodes
Photonics design theory enhancing light extraction efficiency in quantum dot light emitting diodes
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DOI：
10.1088/2515-7639/ac9e77
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发表时间：
2022-10
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影响因子：
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通讯作者：
Diyar Mousa Othman;Julia A Weinstein;Quan Lyu;Bo Hou
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作者：
Diyar Mousa Othman;Julia A Weinstein;Quan Lyu;Bo Hou
量子点发光二极管（QLED）的外量子效率（EQE）需要提高，以实现更高能效的器件。主要限制之一是光提取效率（LEE）较低。通常，在发光层内部产生的光只有20%能从器件射出进入空气，其余的则因波导、衬底模式以及表面等离子体激元而损失。此前已经测试了不同的光子结构来帮助提取被困在器件内部的光。在此我们报道一种光子学设计，它是纳米柱和光栅结构的组合，用于提高QLED的光提取效率。已经研究了改变纳米柱高度、半径和材料的影响。研究发现，间距为500nm、高度为200nm、宽度为400nm的氧化锌纳米柱，以及宽度和间距为150nm的光栅结构，可以使460nm处的光提取效率提高50%，640nm处提高20%。还发现不同的材料有助于提取不同波长的光。二氧化钛纳米柱提高了约590nm区域的提取效率，这是其他材料所没有观察到的。由于全球约19%的电力消耗用于照明应用，提高光提取效率可以显著降低功耗。
The external quantum efficiency (EQE) of quantum dot light emitting diodes (QLEDs) needs improvement for more power-efficient devices. One of the main limitations is the low light extraction efficiency (LEE). Generally, only 20% of the light that is generated inside the emissive layer makes its way out of the device into air, with the rest being lost to waveguide and substrate modes and surface plasmon polaritons. Different photonics structures have been previously tested to help extract the light that is trapped inside the device. Here we report a photonics design which is a combination of nanopillars and grating structures for improving the LEE of QLEDs. The effect of changing the nanopillar height, radius and material has been studied. It was found that ZnO nanopillars of 500 nm pitch, 200 nm height and 400 nm width alongside 150 nm width and pitch grating structure can increase the LEE at 460 nm by 50% and at 640 nm by 20%. It was also found that different materials can help extract light at different wavelengths. TiO2 nanopillars increased the extraction efficiency at ∼590 nm region which was not observed by the other materials. As around 19% of the world’s electricity consumption is due to lighting applications, increasing the LEE can significantly reduce the power consumption.