count existing electric fields between microcrystallites of optically excited films, which cause an acceleration of the radiative recombination process, as compared with the nonradiative processes always present in single and polycrystalline material. A detailed experimental study of this behavior is still in progress, and electroluminescence excitation seems the appropriate means. At the same time, it should be possible to make clear whether the large room temperature green photoluminescence is a sufficient indication of a high efficient electroluminescence device.
SummaryIn this work, we have shown that CBD CdS films prepared with approximately equal amounts of Cd and S ions give films whose green emission persists up to room temperature. There are two ways to achieve this situation: by preparing films whose pH value of the working solution corresponds to equal amounts of Cd and S ion concentrations; or by thermally annealing samples whose S ion concentration exceeds the Cd ion concentration. The mechanism for red luminescence is not affected by these processes. The green emission line is strongly influenced Cds FILMS 2977 by this situation. We have tried to identify the green emission line with a complex transition between Cd and S ion vacancies present in dislocated films.ABSTRACT A heterojunction solar cell made by sequential electrodeposition of CdS and a surfactant aluminum phthalocyanine, (SA1Pc), onto ITO (Nesatron) conductive glass, has been analyzed. Barrier formation occurs upon light absorption and is related to "doping" of the organic pigment by trapped electrons. When the cell is illuminated with white light, all the band bending occurs in the phthalocyanine, and two mechanisms are at work in relation to current production. The optimum thickness for the CdS and SA1Pc layers was found to be 4000 and 2500•, respectively. The photovoltaic characteristics of the optimized cell, under an illumination of 50 mW cm -2, were: Jsc = 0.33 mA cm -2, Voc = 0.46V, ff = 0:3, and = 0.09%. From capacitance measurements a density of N z-3 • 1017 charge carriers/cm 3 was calculated, and the barrier parameters were: Wo -300~ and Vo -0.5V. To illustrate how the junction changes with "doping" of the organic layer by photogenerated electrons, an energy level diagram of the proposed model is presented. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on 2015-07-01 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on 2015-07-01 to IP Vol. 131, No. 12 SOLAR CELL PHOTOELECTRIC PROPERTIES 2979 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on 2015-07-01 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 134.129.182.74 Downloaded on ...