1.Screen printed Solar cell manufacturing technology The solar cells printed with screen printing were developed for the first time in the 1970s. The most mature solar cell manufacturing technology. It involves cutting a wafer of 10 * 10 square cm, 0.5 mm thick, this wafer is doped with p. Born to add holes. The main advantage of screen printing is the relative simplicity of the process. It gives a significant reduction in the cost of processing with almost the same efficiency. The printing of the solar cell screen can be controlled in such a way that it does not introduce any significant contact resistance. The screen-printed solar cells can be optimized for use at concentrations as high as 30.2. Buried Contact fabrication technology The BC solar cell concept 1 was invented at the University of New South Wales by Green et al. in 1983 and it was patented in 1985 2. The buried contact solar cell is a high efficiency commercial solar cell technology based on a metal contact plated inside a groove formed by laser. The buried contact solar cell has a performance up to 25% better than commercial solar cells with screen printing. The shading losses are from 2 to 3%. Without having a wide strip of metal on the top surface as in the latter case, and an aspect ratio of metal height and width increases the efficiency of the cell.Steps for the manufacture of buried contact solar cells: -(1) Elimination of saw damage, texture and cleaning of p-type silicon wafers(2) Deposition of P2O5 / n-type junction formation: heating the wafer in an oven (800-10000C) in a phosphorus atmosphere causes small amounts of phosphorus to be incorporated into the silicon surface(3) CVD (chemical vapor deposition) of silicon nitride over P2O5(4) Laser Groove:(5) Etching and cleaning of damage in the groove(6) Diffusion of heavy phosphorus POCl3 and coding of surface P2O5(7) Aluminium evaporation in the back(8) Rear contact diffusion(9) Sintering:The wafer is held at high temp for a long period of time to melt the aluminium into the silicon and to further diffuse the phosphorus into the silicon.(10) Electrolytic plating of Cu / Ni / Ag(11) Etching(12) Edge isolation: The edges of the wafer are then cut and isolated.The efficiency advantages of buried contact technology provide significant cost and performance benefits. In terms of $ / W, the cost of a buried contact solar cell is the same as that of a solar cell printed with a screen 3. However, due to the inclusion of certain costs related to the area, as well as the fixed costs in a photovoltaic system, a more efficient solar cell technology results in a lower cost of electricity. Another advantage of buried contact technology is that it can be used for concentrator systems 4.When compared to a screen printed cell, the metallization scheme of a buried contact solar cell also improves the cell emitter. To minimize resistive losses, the region of the emitter of a solar cell printed with screen printing is highly doped and results in a “dead” layer on the surface of the solar cell. Since the emitter losses are low in a buried contact structure, the doping of the emitter can be optimized for high open circuit voltages and short circuit currents. In addition, a buried contact structure includes a selective self-aligning emitter, which thereby reduces contact recombination and also contributes to high open circuit voltages.V.APPLICATIONThe invention of solar cells for practical scales and their implementation for the generation of energy in space vehicles has modified and alleviated the work of space research.The sun’s rays do not need any means to flow, these rays are available in space and are used by solar cells for the power requirements of space vehicles.Therefore, in space vehicles, D.C batteries are only used for the storage of energy, and are not the only source of power generation, since the solar cells are installed.The solar energy available in space is literally billions of times larger than what we use today. As Earth receives a small fraction of the 2.3 billion of the Sun’s production, space solar energy is by far the largest potential energy source available, dwarfing all others together.Water pumping: solar pumps are used for two applications, village water supply and irrigation. Since villages need a lot of water, measures must be taken for water storage during a period of low isolation.The photovoltaic panel is flexible and can be used to charge the phone or battery inside and can be re-rolled for storage.VI.FUTURE SCOPEThe fastest growing energy technology in the world is solar, but it is very different from passive solar energy. Photovoltaic solar collectors capture solar energy in a highly adaptable and portable way. Photovoltaic panels and films, made mostly of silicon, convert sunlight into electricity by allowing sunlight to stimulate electrons to a higher level of energy, and then convert that energy into electrical current.Most photovoltaic installations are small, designed primarily to supply a single building, or even a single device, like my electric fences, but solar power stations are increasing in number.The manufacture of photovoltaic energy is a big business, increasingly bigger. In the 21st century, solar energy has already become part of everyday life.From solar-heated swimming pools to solar-powered homes, there are many examples that demonstrate the useful application of clean, safe and sustainable energy from the sun. As concern grows over the effects of burning fossil fuels and the possibility of depleting non-renewable energy sources, the future of solar energy seems bright.Sunlight can be used simply to heat the water, which is then used to provide central heating to homes. Alternatively, it can be used to generate electricity using photovoltaic (PV) cells arranged in solar panels.The solar panel is silent, free of contamination, for life and requires less maintenance.