![]() ![]() ![]() As more photogenerated carriers are produced with the increase of infrared illumination intensity, the external quantum efficiency (EQE) of the QLED unit in the up-conversion device remains little changed. A good balance could be achieved between the absorption of 980 nm incident light and the out-coupling of the 634 nm emission when the active layer thickness is 140 nm, leading to the best performance of the up-conversion device. We regulated the equilibrium between infrared absorption and visible emission by changing the thicknesses of infrared active layers in up-conversion devices. One of the important reasons is the performances of the PD and QLED units restraining each other. However, large efficiency loss is usually induced by the integration of the detecting unit and the emitting unit. The quantum dot up-conversion device combines an infrared photodetector (PD) and a visible quantum-dot light-emitting diode (QLED) to directly convert infrared targets to visible images. ![]()
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