关键词: 染料敏化纳米晶TiO2电极, TBP, 光谱电化学, 能带结构, 陷阱态

Abstract: The flat band edges (Efb) of nanostructured TiO2 electrodes in electrolyte solutions with tert-butylpyridine (TBP) of different concentrations have been determined with spectroelectrochemical technique. TBP played a role in band energetics of nanostructured TiO2 electrodes. The Efb values of -2.25, -2.46 and -2.62 V were determined in three 0.2 mol•L-1 tetrabutylammonium perchlorate (TBAP) acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively. The addition of Li+ ions shifted Efb positively. The Efb values of -1.12, -1.22 and -1.30 V were determined in three 0.2 mol•L-1 LiClO4 acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively. The trap state distribution was investigated by the measurements of time resolved current. The total trap state densities of 3.52 × 1016, 3.18 × 1016 and 3.37 × 1016 cm-2 were determined in three 0.2 mol•L-1 TBAP acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively with trap distribution maximum located at -1.99, -1.89 and -1.85 V. The addition of Li+ ions further reduced the trap state densities. The total trap state densities of 8.39 × 1015, 1.11 × 1016 and 9.22 × 1015 cm-2 were determined in three 0.2 mol•L-1 LiClO4 acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively with trap distribution maximum located at -0.72, -0.84 and -0.95 V. Finally the nanostructured TiO2 electrodes were sensitized with dye N3 and their photoelectrochemical properties were studied in electrolytes with TBP of different concentrations. Experiment results showed that as the concentration of TBP increased, the photoelectric conversion efficiency increased due to improved Voc.