In order to characterize hot carrier populations in semiconductors, photoluminescence measurement is a convenient tool, enabling us to probe the carrier thermodynamical properties in a contactless way. However, the analysis of the photoluminescence spectra is based on some assumptions which will be discussed in this work. We especially emphasize the importance of the variation of the material absorptivity that should be considered to access accurate thermodynamical properties of the carriers, especially by varying the excitation power. The proposed method enables us to obtain more accurate results of thermodynamical properties by taking into account a rigorous physical description and finds direct application in investigating hot carrier solar cells, which are an adequate concept for achieving high conversion efficiencies with a relatively simple device architecture.