Single-crystal, n-type, undoped CdS and Te-doped CdS (100 and 1000 ppm CdS:Te) electrodes exhibit electroluminescence (EL) in aqueous, alkaline peroxydisulfate electrolyte. Addition of Te to CdS introduces intraband gap states which drastically alter the EL spectral distribution. The EL spectrum of undoped CdS consists of a sharp band near the band gap energy (~2.4 eV) with Xmax ~510 nm and a weaker, broader band at lower energy; the EL spectra of 100 and 1000 ppm CdS:Te also exhibit a sharp band at ~510 nm but are dominated by broad bands with uncorrected Xmax ~600 and ~620 nm, respectively. Photoluminescence (PL) spectra, obtained with 457.9-nm excitation, aid in the assignments of the emissive transitions; PL spectra are generally similar to their EL counterparts. The potential dependence of the EL spectra was examined between ~-1.2 V (onset) and -2.0 V vs. SCE, Changes in potential can affect both the relative and absolute intensities of the bands present in the EL spectra. Lower-limit, order-of-magnitude estimates of instantaneous EL efficiency, $el, have been made. Under steady-state conditions 0el is iílO-6 for undoped CdS and itlO""6 for CdS:Te. Results are discussed in terms of interfacial charge-transfer processes and the excited-state manifolds of CdS and CdS:Te.

An alternating current (ac) resistance technique for sodium‐sulfur cells is described. The method has been applied to central sodium and central sulfur cells with between 16 and 650 Ah capacity. The shape of the ac charge resistance‐capacity plot has been correlated with resistive layer composition. Anomalies in direct current (dc) resistances for oriented‐mat sulfur electrode cells are explainable in conjunction with ac analysis. The increased sensitivity of ac compared to dc measurements has been utilized to identify incipient electrolyte failure and sodium electrode problems not discernable by the latter technique.

Data are presented on the electronic conductivity and molten alkali carbonate stability (Li:K binary of 62:38 mole ratio) of various materials at 923 K under a 30% CO2/normalair atmosphere. Of the examined materials, only LaNiO3 and LaxSr1−xCoO3 satisfied both criteria sufficiently for acceptable use as molten carbonate fuel cell cathode materials.

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Correlations among quantum efficiencies for photocurrent (rpx), emission (rp,), and non-radiative recombination (rp,,) are discussed with reference to data from single-crystal, n-type, 100 and 1000 p.p.m. CdS : Te-based photoelectrochemical cells (PECs) employing aqueous sulphide electrolyte. These materials emit while they serve as PEC electrodes. The assumption that the proportionality of rpr to rpnr is unaffected by potential, leads to a simple expression relating rp, to rp, for monochromatic excitation. Calculated and observed emission data are in reasonable agreement ; sources of deviation are discussed. Polychromatic excitation is shown to yield photocurrents and emission intensities which are approximately a weighted average of the values obtained with theconstituent monochromatic frequencies. Practical implications of the q x correlation with rp, are described, as are related results from other PECs.