Electron lifetime and diffusion coefficient measurements in highly efficient porphyrin-sensitised TiO2 solar cells showed reduced electron lifetime, and consequently, lower photo-induced electron density under illumination compared to commonly used ruthenium dye (N719)-sensitised solar cells, which is proposed to be the origin of the generally lower open circuit voltage.
Mozer, A. J., Wagner, P. W., Officer, D. L., Wallace, G. G., Campbell, W. M., Miyashita, M., Sunahara, K. & Mori, S. (2008). The origin of open circuit voltage of porphyrin-sensitised TiO2 solar cells. Chemical Communications, 4741-4743.