Hole injection from P1 dye hot-excited states in p-type dye-sensitized films: a fluorescence study

We present a study of the excited state relaxation dynamics photosensitizer P1 used in p-type dye-sensitized solar cells. Comparative femtosecond fluorescence upconversion measurements solution and films show that dye undergoes picosecond electronic from bright Franck–Condon (FC) to low-emitting charge-transfer (CT) polar environment. The is moderately quenched on mesoporous Al2O3 isolator but dramatically more NiO semiconductor. assign this sub-picosecond process hole injection thus confirming electron transfer FC directly into valence band.