Temperature significantly modifies the efficiencies of luminescence and photocurrent in an n‐type, single crystal, normalCdS:normalTe‐normalbased photoelectrochemical cell (PEC) employing aqueous polyselenide electrolyte. Between 20° and 100°C photocurrent (quantum yield Φx ) from ultrabandgap 501.7 nm excitation increases modestly by ≲ 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 normalCdS exhibits a similar photocurrent‐temperature profile. Higher temperatures thus extend the wavelength response of normalCdS ‐ and normalCdS:normalTe‐normalbased PEC's. In contrast to the increase in photocurrent, emissive efficiency (quantum yield Φr ) of normalCdS:normalTe drops by a factor of ∼10–20 over the same temperature range; this decline is relatively insensitive to potential and excitation wavelength (501.7 or 514.5 nm). Little change in the spectral distribution of emission false(λmax∼600 normalnmfalse) is observed with temperature. A dependence of emission intensity on potential is observed for the first time with 514.5 nm excitation in the high temperature regime. These results are interpreted in terms of band bending, optical penetration depth, the known red‐shift of the normalCdS bandgap edge with temperature, and the competitive nature of emission and photocurrent. Relationships among Φx , Φr , and Φr0/Φr (out‐of‐circuit to in‐circuit emission intensity) are discussed.

Die Temp. modifiziert die relativen Ausb. der Lumineszenz und des Photostroms in photoelektrochemischen Zellen auf der Grundlage von n‐leitenden, einkristallinen CdS :Te oder CdS mit wäßrigen Polyselenid‐Elektrolyten signifikant, was die konkurrierende Natur dieser beiden Deaktivierungswege für angeregte Zustände unterstreicht.