Thermal Manipulation of Deactivation Processes in Luminescent Photoelectrochemical Cells Employing Tellurium-Doped Cadmium Sulfide Photoelectrodes

摘要

Temperature significantly modifies the efficiencies of luminescence and photocurrent in an n-type, single crystal, CdS:Te-based photoelectrochemical cell (PEC) employing aqueous polyselenide electrolyte. Between 20 and 100 C photocurrent (quantum yield phi sub x) from ultraband gap 501.7 nm excitation increases modestly by less than or = 20%, whereas photocurrent from bandgap edge 514.5 nm excitation increases by about an order of magnitude, reaching 50-100% of the 20 C 501.7 nm photocurrent. Undoped CdS exhibits a similar photocurrent-temperature profile. Higher temperatures thus extend the wavelength response of CdS- and CdS:Te-based PEC's. In contrast to the increase in photocurrent, emissive efficiency (quantum yield phi sub r) of CdS:Te drops by a factor of approximately 10-20 over the same temperature range; this decline is relatively insensitive to potential and excitation wavelength (501.7 or 514.5 nm).