The light intensity dependence of the main photoelectrical parameters of the nonfullerene small-molecule bulk heterojunction (BHJ) solar cells p-DTS(FBTTh2)2:perylene diimide (T1:PDI) shows that the nongeminate recombination losses play an important role in this system. A simple approach for the quantitative analysis of capacitance spectroscopy data of the organic BHJ solar cells, which allows to determine the density of free charge carriers as a function of applied bias under standard working conditions, is demonstrated. Using the proposed capacitance spectroscopic technique, the nongeminate recombination losses in the T1:PDI solar cells are quantitatively characterized in the scope of the bimolecular- and trap-assisted recombination mechanisms. Their contributions are separately analyzed within a wide range of the applied bias.
- bulk heterojunction solar cells
- charge-carrier recombination
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)