Photoinduced charge separation in donor-acceptor spiro compounds at metal and metal oxide surfaces. Application in Dye Sensitized Solar Cell

MACOR, L., GERVALDO, M., FUNGO, F., OTERO, L., DITTRICH, T., LIN, C-Y., CHI, L-C., FANG, F-C., LII, S-W., WONG, K-T., TSAID, C-H, WU, C-C

RSC Advances

Royal Society of Chemistry

Año: 2012 vol. 2 p. 4869 - 4878

2046-2069

Modulated charge separation has been investigated by surface photovoltage spectroscopy in the fixed capacitor arrangement for four different fluorenecompounds adsorbed from highly diluted solutions at ultra-thin nanoporous TiO2 (np-TiO2), Au and ITO surfaces. Donor (-N(C6H5)2) and acceptor moieties (-CN, -COOH) were linked by fluorene or spirobisfluorene cores and the chain length has been changed by introducing thiophene. Modulated charge separation by electron injection< and intramolecular transport has been separated and directed adsorption of spiro compounds at Au surfaces has been demonstrated. Striking differences between the< interaction of linking -CN and -COOH groups and the different substrates were observed. The capability as TiO2 spectral sensitizer of spirobifluerene Donor-Acceptor molecules with extended conjugation has been demonstrated. Solar cells exhibit 5.6% energy conversion efficiency, confirming that spiro-configured geometry is a promising route to the design of metal free dyes.