The mean photon energy of a light-emitting diode (LED) as recently defined in the IEC standard is theoretically examined. It is pointed out that defining the mean photon energy as an arithmetic mean of photon energies in the emission spectrum is crucial in decomposing the power efficiency of an LED into the voltage efficiency and the external quantum efficiency (EQE). The mean photon energy thus defined and the photon energy calculated from the more convenient peak wavelength in the spectrum are then evaluated and compared for blue and red LED samples. The EQEs of the blue and red LEDs are subsequently obtained, demonstrating that the EQE values from the peak photon energy have small errors within 0.5%p of the true EQE values. The current work presents useful criteria in substituting the EQE value calculated from the peak wavelength for the true EQE value using the mean photon energy for both the blue and red LEDs.

中文翻译：

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理解和评估发光二极管的平均光子能量和外量子效率

对最近在 IEC 标准中定义的发光二极管 (LED) 的平均光子能量进行了理论上的检验。指出将平均光子能量定义为发射光谱中光子能量的算术平均值对于将 LED 的功率效率分解为电压效率和外部量子效率 (EQE) 至关重要。这样定义的平均光子能量和从光谱中更方便的峰值波长计算的光子能量然后被评估和比较蓝色和红色 LED 样品。随后获得蓝色和红色 LED 的 EQE，表明来自峰值光子能量的 EQE 值与真实 EQE 值的误差在 0.5%p 以内。