10-Charge separation in donor-acceptor spiro compounds at metal and metal oxide surfaces investigated by surface photovoltage

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

STRASBOURG-FRANCIA

Simposio; Symposium H, E-MRS-European Material Research Society; 2012

Resume : Molecules with donor (diphenylamine) and acceptor moieties (dicyano or cyanoacrylic acid moieties) were linked by fluorene or spirobisfluorene cores and the chain length has been changed by introducing a thiophene group between fluorine and diphenylamine. Four different kinds of fluorene and spirobisfluorene compounds were adsorbed from highly diluted solutions at ultra-thin nanoporous TiO2 (np-TiO2), Au and ITO surfaces. Charge separation has been investigated by surface photovoltage spectroscopy in the fixed capacitor and Kelvin probe arrangements in vacuum and argon atmosphere. Striking differences between the interaction of linking dicyano or cyanoacrylic moieties and different substrates were observed. Charge separation by electron injection and intramolecular transport has been separated and the role of directed adsorption of spiro compounds is discussed.