Abstract: An improved spray booth is provided for use in forming high quality thin films by controlling the spray parameters related to film formation. A spray nozzle design is selected which permits control of the spray footprint on a heated substrate. A projected atomized liquid is formed to the selected spray configuration by directing spray cones of air toward the atomized liquid. Dwell time of the spray material adjacent the hot substrate is then controlled by controlling the velocity of airflow within the spray chamber and adjacent the substrate. To promote a gas phase reaction, a roof section is provided with reduced airflow wherein sufficient dwell time is provided for the vapor reaction to occur. Where a liquid phase reaction is provided, high velocity airflow is maintained to promptly remove reaction products and spray material which has not reached the surface after a selected time period.

Abstract: A photovoltaic cell having an electrically conductive substrate, which may be glass having a film of conductive tin oxide; a first layer containing a suitable semiconductor, which layer has a first component film with an amorphous structure and a second component film with a polycrystalline structure; a second layer forming a heterojunction with the first layer; and suitable electrodes where the heterojunction is formed from a solution containing copper, the amorphous film component is superposed above an electrically conductive substrate to resist permeation of the copper-containing material to shorting electrical contact with the substrate. The penetration resistant amorphous layer permits a variety of processes to be used in forming the heterojunction with even very thin layers (1-6.mu. thick) of underlying polycrystalline semiconductor materials.

Abstract: A photovoltaic cell is formed by combining a spray process, forming a crystalline layer containing cadmium and sulfur, and an evaporation process, depositing copper chloride for converting to Cu.sub.x S. The crystals containing cadmium and sulfur are heated in an atmosphere of cadmium and chlorides to obtain crystals having at least one dimension greater than 0.5 micron and a planar layer of Cu.sub.x S is formed on the large crystals. A layer of Cu.sub.x S having a thickness of 0.5-1.0 micron is obtained. Electrodes are formed from evaporated gold or chromium or a metallic paste including silver or copper. Zn.sub.x Cd.sub.1-x S may be substituted for CdS through at least part of the crystalline layer for improved Voc.

Abstract: A photovoltaic cell is formed by combining a spray process, forming a crystalline layer containing cadmium and sulfur, and an evaporation process, depositing copper chloride for converting to Cu.sub.x S. The crystals containing cadmium and sulfur are heated in an atmosphere of cadmium and chlorides to obtain crystals having at least one dimension greater than 0.5 micron and a planar layer of Cu.sub.x S is formed on the large crystals. A layer of Cu.sub.x S having a thickness of 0.5-1.0 micron is obtained. Electrodes are formed from evaporated gold or chromium or a metallic paste including silver or copper. Zn.sub.x Cd.sub.1-x S may be substituted for CdS through at least part of the crystalline layer for improved Voc.

Abstract: A pattern of transparent conductive material, such as tin oxide, is formed on a transparent vitreous substrate using a polycrystalline material, such as cadmium or zinc sulfide, to mask the substrate surface while depositing material forming the transparent conductive layer. The polycrystalline material and any overlying transparent conductive material are easily removed by a chemical etch, leaving the desired pattern of transparent conductive material adhering to the substrate. Two electrically conductive patterns may be formed in intersecting relationship and isolated, one from the other. The degree of electrical connection between the two patterns will be a function of the resistance of the polycrystalline material therebetween at points of crossing. In some instances, electroluminescence may be obtained by selecting the proper crystalline material wherein an electrical display may be created by selectively energizing crossing electrical conductors.

Abstract: An improved conveyor assembly is provided for transporting a transparent vitreous substrate along a group of controlled radiative heaters. A plurality of control groups are formed from the radiative heaters and the illumination for the various control groups is isolated so that areas of the conveyor or substrate are illuminated by only a single control group at any one time. Heater control thermocouples are affixed to the radiative heater elements and the output signals from the control thermocouples are calibrated from a calibration thermocouple extending to a position between the control thermocouple and the substrate surface. A wire mesh belt assembly permits illumination of the substrate through the conveyor assembly while supporting the substrate in a manner effective to obtain uniform heating of the substrate.

Abstract: An array of photovoltaic cells in a back wall-type configuration supported by a rigid transparent vitreous substrate, such as glass, for admitting incident radiation to the cells. A plurality of cells are interconnected into a desired electrical configuration by one or more layers of electrically conducting materials which overlie the entire heterojunction of each cell to minimize the internal resistance of the cell and may conveniently protect the heterojunction from degrading environmental conditions. Various component layers forming the photovoltaic cells are selectively removed and strips of insulating material are applied prior to forming the heterojunction. The electrically conductive material is thereafter applied and separated at areas protected by insulating material. The resulting series array contains no exposed heterojunction areas, thereby obtaining improved operating stability and performance.

Abstract: Methods and apparatus are provided for forming films of materials which are component layers of solar energy conversion devices, e.g. photovoltaic cells and heat collector panels. A selected substrate, generally glass, is heated while being sprayed with solutions which react on the heated surface to form a particular film. Films of SnO.sub.x and CdS are particularly produced. According to the present invention, a thermal energy input gradient is provided to approximate the energy loss gradient during the spray process. Radiative heaters provide a rapid resupply of energy to the substrate and, in some instances, directly to the film forming surface. Temperature detectors, such as thermocouples, monitor substrate temperature to provide the radiative energy input needed for substantial temperature uniformity.

Abstract: A photovoltaic cell having an electrically conductive substrate, which may be glass having a film of conductive tin oxide; a first layer containing a suitable semiconductor, which layer has a first component film with an amorphous structure and a second component film with a polycrystalline structure; a second layer forming a heterojunction with the first layer; and suitable electrodes where the heterojunction is formed from a solution containing copper, the amorphous film component is superposed above an electrically conductive substrate to resist permeation of the copper-containing material to shorting electrical contact with the substrate. The penetration resistant amporphous layer permits a variety of processes to be used in forming the heterojunction with even very thin layers (1-6.mu. thick) of underlying polycrystalline semi-conductor materials.

Abstract: A large area photovoltaic cell comprising a layer of polycrystalline cadmium sulfide, about 1 to 2 microns thick, formed by simultaneously spraying two suitably selected compounds on a uniformly heated plate of Mesa glass and irradiating the layer of polycrystalline cadmium sulfide with intense ultra-violet light during the spraying.

Abstract: A method of producing an array of photovoltaic cells responsive to incident radiation by forming heterojunction-forming material layers over a transparent substrate panel having a transparent electrically conductive coating and thereafter removing selected portions of the materials to form a plurality of cells on a common substrate. The cells are then electrically interconnected by depositing electrically conducting materials over substantially the entire panel and removing only those portions of the deposited materials required to form series electrical connections.

Abstract: An array of photovoltaic cells in a back wall-type configuration supported by a rigid transparent vitreous substrate, such as glass, for admitting incident radiation to the cells. A plurality of cells are interconnected into a desired electrical configuration by one or more layers of electrically conducting materials which overlie substantially the entire heterojunction of each cell to minimize the internal resistance of the cell and may conveniently protect the heterojunction from degrading environmental conditions. The conducting layer interconnects an exposed electrode region of one cell with the heterojunction forming material of the adjacent cell while remaining insulated from any intervening cell structure. In one embodiment, the uppermost conducting layer is lead, which seals the underlying materials from atmospheric constituents, such as oxygen and water vapor, while remaining relatively inert to such constituents.

Abstract: Methods and apparatus are provided for forming films of materials which are component layers of solar energy conversion devices, e. g. photovoltaic cells and heat collector panels. A selected substrate is heated while being sprayed with solutions which react on the heated surface to form a particular film. Films of SnO.sub.x and CdS are particularly produced. According to the present invention, the spray is projected at an angle to control upstream flow and confine film formation to the substrate panel portions most suitable for forming the selected film. Various waste products are removed to minimize defects in the resulting film. Baffles are located to shield the substrate surface at selected areas and preclude the spray from impacting on the shielded areas.

Abstract: A solar panel module is provided, wherein a plurality of solar panel units are electrically interconnected and supported within a low cost frame assembly, which may conveniently be formed from wood products. Each solar panel unit is provided with extending conductors for electrical connections with adjacent solar panels. Each solar panel unit is formed in a back-wall configuration where solar radiation is incident on a transparent vitreous substrate. The panel surface opposite the substrate is sealed, preferably with a bituminous material, to minimize permeation of the solar panel by environmental elements. The sealing material cooperates with the frame to provide an insulated exposed surface. In one embodiment, the completed module is formed to external dimensions generally standard in the building industry for easy installation.

Abstract: An apparatus is provided for forming a large area photovoltaic cell into a plurality of photovoltaic cells on a common substrate and preparing the individual cells for an overlying layer of conductive material. A tool bit is urged against the polycrystalline materials forming the heterojunction to remove a preselected pattern and expose a layer of conductive material, tin oxide, on a supporting glass substrate. Tool bit pressure causes fracturing of the crystals to produce defined edges along the tool bit furrow. An electrical arc is produced to vaporize a portion of the exposed tin oxide to electrically isolate the individual photovoltaic cells. Applicator pens coat the edges of the polycrystalline material with preselected insulating films. Finally, a buffer wheel abrades a preselected metal onto the remaining exposed surface of the tin oxide to obtain an improved metallurgical and/or electrical contact between the tin oxide and the subsequent conductor layer.

Abstract: Methods and apparatus are provided for forming films of materials which are component layers of solar energy conversion devices, e.g. photovoltaic cells and heat collector panels. A selected substrate, generally glass, is heated while being sprayed with solutions which react on the heated surface to form a particular film. Films of SnO.sub.x and CdS are particularly produced. According to the present invention, a thermal energy input gradient is provided to approximate the energy loss gradient during the spray process. Radiative heaters provide a rapid resupply of energy to the substrate and, in some instances, directly to the film forming surface. Temperature detectors, such as thermocouples, monitor substrate temperature to provide the radiative energy input needed for substantial temperature uniformity.

Abstract: A method for producing a solar cell having an increased open circuit voltage. A layer of cadmium sulfide (CdS) produced by a chemical spray technique and having residual chlorides is exposed to a flow of hydrogen sulfide (H.sub.2 S) heated to a temperature of 400.degree.-600.degree. C. The residual chlorides are reduced and any remaining CdCl.sub.2 is converted to CdS. A heterojunction is formed over the CdS and electrodes are formed. Application of chromium as the positive electrode results in a further increase in the open circuit voltage available from the H.sub.2 S-treated solar cell.

Abstract: An improved method for fabrication of a photovoltaic cell preferably of the CdS--Cu.sub.x S type, having a copper electrode adjacent the Cu.sub.x S. A portion of the CdS is converted to Cu.sub.x S through ion exchange wherein the CdS is immersed in a first solution of cuprous ions and a second solution of cupric ions to produce a non-stoichiometric Cu.sub.x S. A layer of metallic copper is applied by conventional techniques, such as vacuum deposition, and the photovoltaic cell heat treated to affect formation of the CdS--Cu.sub.x S heterojunction. Metallic copper diffusing through the CdS and Cu.sub.x S from the electrode is captured by the non-stoichiometric Cu.sub.x S whereby the Cu.sub.x S is substantially stoichiometric in the completed photovoltaic cell.

Abstract: A method of making low cost solar cells on a large scale basis by means of a continuous process of fabricating float glass and coating the float glass, in sequence, with tin oxide, cadmium sulphide, and copper sulphide, while the glass floats atop tanks of molten material in a furnace of proper temperature for each step of the process, the application of the coatings, in a preferred embodiment, being accomplished by depositing materials which form the coatings on contact with heated surfaces at such slow rates and, in the case of spray application, via drops of such uniformity that the float glass may (1) remain at uniform temperatures by virtue of the superior thermal conductivity of the molten material and retain those temperatures despite the abstraction of heat from the glass by evaporation of liquids and/or formation of crystalline layers, and (2) be substantially free of temperature gradients along the surface of the sheet glass.

Abstract: A photovoltaic cell having an electrically conductive substrate, which may be glass having a film of conductive tin oxide; a first layer containing a suitable semiconductor, which layer has a first component film with an amorphous structure and a second component film with a polycrystalline structure; a second layer forming a heterojunction with the first layer; and suitable electrodes where the heterojunction is formed from a solution containing copper, the amorphous film component is superposed above an electrically conductive substrate to resist permeation of the copper-containing material to shorting electrical contact with the substrate. The penetration resistant amorphous layer permits a variety of processes to be used in forming the heterojunction with even very thin layers (1-6.mu. thick) of underlying polycrystalline semi-conductor materials.