LUMINESCENT PHOTOELECTROCHEMICAL CELLS - 6. SPATIAL ASPECTS OF THE PHOTOLUMINESCENCE AND ELECTROLUMINESCENCE OF CADMIUM SELENIDE ELECTRODES.

Samples of single-crystal, n-type CdSe emit when excited with ultraband gap excitation. The emission band ( lambda //m//a//x approximately equals 720 nm) is near the band gap of CdSe (approx. 1. 7 ev); its energy, decay time, and temperature dependence are consistent with its description as edge emission. Photoluminescence (PL) spectra can be dependent on excitation wavelength and show evidence of self-absorption effects: Pl spectra obtained with 457. 9-nm excitation are broadened in the high-energy portion of the band relative to spectra obtained with more deeply penetrating 632. 8-nm excitation. Measured PL efficiencies, phi //r, are approx. 10** minus **4 in air at 295 K. When CdSe is used as the photoanode of photoelectrochemical cells employing aqueous polychalcogenide electrolytes, emission is quenched by the passage of photocurrent resulting from ultraband gap excitation. Electroluminescence (EL) can be observed from CdSe when the semiconductor is used as a dark cathode is aqueous, alkaline peroxydisulfate electrolyte.