Kelvin probe force microscopy at air in the dark and under illumination by visible light was performed for electrodeposited porous ZnO films, which were sensitized by the indoline dye D149. A contact potential difference was measured that confirmed electron injection into the semiconductor matrix and their subsequent stabilization in trap states. A locally widely homogenous signal was observed speaking in favor of a wellcrystallized sample. The rise and decay times of the photovoltage in the ms to s timescale could be analyzed by use of individual scan lines or scanned images, respectively. The results are discussed in the context of recent pump-probe spectroscopy results as well as such from photoelectrochemical experiments with such electrodes and implications will be deduced for their use in dye-sensitized solar cells.