Abstract: The photovoltaic properties of dimeric porphyrin have been studied by means of surface photovoltage spectrum(SPS) and fielDInduced surface photovoltage spectrum(FISPS). The results show that a negative SPVresponse band(P) appears in the long-wave region which takes on n type character and the π-π ^* transition band takes on p type character. Pband disappears under high vacuum and appears under O₂ atmosphere. The photo-charge-transfer process generated between π-π ^* transition band of dimeric porphyrin and Pband, which has been attributed to the photo adsorption and photo desorption of O₂ on the surface of dimeric porphyrin.

Key words: Surface photovoltage spectrum, Charge transfer process, Dimeric porphyrin, FielDInduced surface photovoltage spectrum