IEC 60747-5-9:2019（E）规定了单个发光二极管（LED）芯片或封装（不含磷光体）内部量子效率（IQE）的测量方法。用于照明应用的白色LED不在本文件范围内。本文件利用了在低温和工作温度下测量的相对外部量子效率（EQE），即温度相关电致发光（TDEL）。为了确定100%的参考IQE，通过改变环境温度和电流找到峰值EQE的最大值。

IEC 60747-5-9:2019(E) specifies the measuring method of the internal quantum efficiency (IQE) of single light emitting diode (LED) chips or packages without phosphor. White LEDs for lighting applications are out of the scope of this document. This document utilizes the relative external quantum efficiencies (EQEs) measured at cryogenic temperatures and at an operating temperature, which is called temperature-dependent electroluminescence (TDEL). In order to identify the reference IQE of 100 %, the maximum values of the peak EQE are found by varying the environmental temperature and current.