IEC TS 63109:2022

IEC TS 63109:2022 specifies a method to measure the diode ideality factor of photovoltaic cells and modules by quantitative analysis of electroluminescence (EL) images. This document provides a definition of the term diode ideality factor _n_, as the inverse of increment ratio of natural logarithm of current as a function of applied voltage, which is related to the fill factor _FF_, and is useful as an effective indicator to represent the output efficiency of photovoltaic cells and modules with the other key parameters open circuit voltage _V_oc and short circuit current _I_sc.