Js. Salafsky et al., CHARGE DYNAMICS FOLLOWING DYE PHOTOINJECTION INTO A TIO2 NANOCRYSTALLINE NETWORK, JOURNAL OF PHYSICAL CHEMISTRY B, 102(5), 1998, pp. 766-769
Electrons can be injected into TiO2 nanocrystals by a surface-adsorbed
Ru-based dye in a well-known photosensitization process. Here we pres
ent time-resolved microwave conductivity measurements of the decay of
electrons out of an electrically interconnected network of such TiO2 n
anocrystals, following charge injection, and in the presence of an ele
ctron donor to the dye cation that prevents direct recombination. The
time scale for this decay process is hundreds of milliseconds to secon
ds and explains the high current collection efficiency in devices base
d on these materials, since the long time scale allows for slow charge
transport through the network.