A high open circuit voltage (VOC) close to 1.4 V under AM 1.5, 100 mW cm−2 conditions is achieved when carbon nanotubes (CNTs) are used as a hole conductor in methyl ammonium lead bromide (MAPbBr3) perovskite solar cells. Time-resolved photoluminescence and impedance spectroscopy investigations suggest that the observed high VOC is a result of the better charge extraction and lower recombination of the CNT hole conductor. Tandem solar cells with all perovskite absorbers are demonstrated with a MAPbBr3/CNT top cell and a MAPbI3 bottom cell, achieving a VOC of 2.24 V in series connection. The semitransparent and high voltage MAPbBr3/CNT solar cells show great potential for applications in solar cell windows, tandem solar cells and solar driven water splitting.
Z. Li, Boix, P. P., Xing, G., Fu, K., Kulkarni, S. A., Batabyal Sudip Kumar, Xu, W., Cao, A., Sum, T. Chien, Mathews, N., and , “Carbon nanotubes as an efficient hole collector for high voltage methylammonium lead bromide perovskite solar cells”, Nanoscale, 2016.