Electron Kinetics in Dye Sensitized Solar Cells Employing Anatase with (101) and (001) Facets
Two phase-pure nanocrystalline anatase materials differing in the exposed crystal facets (001) or (101) are studied by electrochemical impedance spectroscopy and by transient photovoltage and photocurrent decay in dye sensitized solar cells. A larger chemical capacitance, indicating larger density of states, is observed for anatase (001). The presence of deep electron traps in (001) nanosheets is further confirmed by optical (UV-Vis) and photoemission (XPS, UPS) spectra. The difference in chemical capacitance indicates a slower diffusion of electrons in the (001) anatase material, but also a higher electron lifetime compared to (101) anatase material. (C) 2015 Elsevier Ltd. All rights reserved.