Quantitative separation of mechanisms for power dissipation in solar cells by photoacoustic and photovoltaic measurements

Photoacoustics is used as a calorimetric method in conjunction with electrical measurements to determine which mechanisms are involved in the conversion of most of the absorbed radiation to thermal energy in (mainly Si p-n) solar cells. The major mechanisms that are identified and quantified include local cooling, near the junction of the cells. Quantification is made possible by the use of a model for internal energy fluxes in a photovoltaic cell, which takes into account the different spatial distributions of heat generated by photogenerated and injected carriers. The experimental results agree well with calculations based on the model also in the case of thin-film CdS/CuInSe₂ cells.