Abstract: Solar cell construction having a body formed essentially of silicon and having a surface with a photovoltaic junction applied thereon. An anti-reflection coating is formed on the surface. A transparent protective cover is provided. A cut-on filter is carried by the cover for reflecting solar energy below approximately 350 nanometers. A layer of substantially transparent cement is used for securing the protective cover to the body so that it overlies the junction and the anti-reflection coating. The cut-on filter includes a stack of high and low index layers for reflecting solar energy in the ultra-violet region of 350 nanometers and below and also may include at least one additional layer of material of absorbing ultraviolet energy below 350 nanometers which passes through the high and low index layers above it.

Abstract: A method for the production of solar cells with a thin-layer PN heterojunction, having a cadmium sulfide layer vapor deposited on an electrically conductive support and a cuprous sulfide layer chemically produced on the cadmium sulfide layer, and having an electrically conductive grid in contact with the cuprous sulfide layer, wherein the two layers and the conductive support are formed into one structural part, and the conductive grid is formed into a second structural part including a covering glass member, and the two structural parts are adhesively joined to form a closed encapsulated cell.

Abstract: Apparatus is disclosed for converting solar energy to more useful forms, i.e., thermal and electrical energy. Such apparatus includes a photoelectric transducer (e.g., an array of photovoltaic cells), means for concentrating solar energy on the transducer, and means for circulating a liquid between the transducer and the solar energy concentrator. The spectral properties of the liquid are such that the liquid functions as a bandpass filter, transmitting solar energy to which the transducer is responsive and absorbing solar energy to which the transducer is non-responsive. The transmitted solar energy is converted to electrical energy by the transducer, and the absorbed solar energy is converted to heat by the liquid. Preferably, the liquid is circulated through a container which, in the vicinity of the transducer, is constructed so as to provide optical gain to the system and to integrate incident solar energy for the purpose of eliminating "hot spots" which could overheat, and thereby damage, the transducer.