Performance of sol-gel SiO2 coatings onto glass/SnO2 superstrate

From commercial glass/SnO2 superstrates, by dipping in an appropriate sol-g el solution, new SiO2/glass/SnO2/SiO2 superstrates have been obtained, with improved transmittance controlled by SiO2 deposition parameters such as th e alcohol/alkoxide ratio in the sol-gel solution and the sample withdrawal velocity. In this way, close to 15% visible transmittance enhancement has b een achieved, without infrared optical losses. The electrical characteristi cs of the sol-gel-coated samples have been evaluated by applying electro-de posited coatings on them. Electrodeposition of a CuInSe2 absorber layer ont o SiO2-coated conducting superstrates has been found to be heterogeneous at low cathodic potentials, but can be made homogeneous by increasing the wor k electrode polarisation, in order to achieve the disruptive voltage for th e SiO2 electrical insulation. (C) 2000 Elsevier Science S.A. All rights res erved.