Hui-Seon Kim, Ivan Mora-Sero, Victoria Gonzalez-Pedro, Francisco Fabregat-Santiago, Emilio J. Juarez-Perez, Nam-Gyu Park & Juan Bisquert
Nature Communications 4, Article number 2242, doi:10.1038/ncomms3242 31 July 2013
Photovoltaic conversion requires two successive steps: accumulation of a photogenerated charge and charge separation. Determination of how and where charge accumulation is attained and how this accumulation can be identified is mandatory for understanding the performance of a photovoltaic device and for its further optimization. Here we analyse the mechanism of carrier accumulation in lead halide perovskite, CH3NH3PbI3, thin-absorber solar cells by means of impedance spectroscopy. A fingerprint of the charge accumulation in high density of states of the perovskite absorber material has been observed at the capacitance of the samples. This is, as far as we know, the first observation of charge accumulation in light-absorbing material for nanostructured solar cells, indicating that it constitutes a new kind of photovoltaic device, differentiated from sensitized solar cells, which will require its own methods of study, characterization and optimization.
“The necessity for developing clean energy technology has led to the surge in renewable energy research. A major effort is in discovering new approaches for producing transportable fuels … During recent years many efforts have been made to develop new light harvesting assemblies, elucidate charge transfer processes and improve the efficiency of water splitting processes. This Virtual Issue presents a few selected publications to highlight recent physical chemistry advances … ”
Prashant V. Kamat and Juan Bisquert