The photoelectrochemical properties of phenylseleniumdiimide films

The photoelectrochemical properties of organoselenium semiconductors (diphenylseleniumdiimide, N,N-(bis-p-methoxyphenyl)seleniumdiimide, N,N-(bis-m-methoxyphenyl)seleniumdiimide, and N,N-(bis-p-bromophenyl)seleniumdiimide) were studied in a photovoltaic system containing an electrolytic contact (metal-semiconductor-electrolyte-metal). The deposition of films on platinum substrates by evaporation of solutions in dimethylsulfoxide produced a porous coating, the photopotential of even most active diphenylse-leniumdiimide did not exceed 91 m V, and short-circuit current did not exceed 0.88 μA. The film of diphenylseleniumdiimide of the same thickness (400 nm) obtained by sublimation in a vacuum (10^?7 torr, 160°C) had photopotential up to 300 mV and short circuit current up to 2.21 μA. The dependence of photocurrent and current quantum yield on electrolyte pH and the thickness of pigment films and the photovoltaic characteristics of pigmented electrodes under pulsed irradiation were studied. The maximum values obtained were photopotential U _ph = 400 mV, photocurrent I _ph = 26 μA, current quantum yield under stationary irradiation η = 8.5%, and quantum yield under pulsed irradiation η* = 23%.