Low-Cost Process for p-N Junction-Type Solar Cell. Final Report, March 1, 1981-May 31, 1982

摘要

Significant progress has been made in the preparation of films and devices for both the spray pyrolyzed and the screen printed and sintered cells. In the spray program, indium-doped CdS films with thicknesses of less than 0.1 cm have been reproducibly deposited. The key to the efficient doping is in the control of the ratio of cadmium chloride to thiourea. We have, for the first time, deposited the chalcopyrite form of CuInsSe sub 2 both on glass and on molybdenum-coated glass. The resistivity of the deposit has been varied through the spray conditions and variations in the amount of copper. Photovoltaic efficiency of the sprayed cell has gradually increased to 2.3 percent, and a significant improvement with time has been observed. The photovoltaic response of the sintered cell has also been improved, although it is still below 1 percent efficiency. It is apparent that the contact to the CdTe layer and the conditions for its conversion to p-type with copper addition to the graphite electrode is critical. The cell response of both types of cells has been studied by a variable-frequency impedance technique. The significant problems for the sprayed cell are low shunt resistance and high dark current, while for the sintered cell there is a high series resistance and a significant interface state density of low time constant. Thermodynamic and chemical kinetic considerations of the sintering process are presented. (ERA citation 08:031393)