65 ISST Journal of Mechanical Engineering, Vol. 6 No. 1, (January - June 2015), p.p. 65-67 ISSN 0976-7371 © Intellectuals Society for Socio-Techno Welfare A NEW SOLAR CELL TECHNOLOGY FOR ULTRA HIGH EFFICIENCY Aman Kumar and Mohd. Parvez Department of Mechanical Engineering, Al-Falah University, Faridabad-121004, Haryana, India E-mail: amanjisinha@yahoo.com, mparvezalig@rediffmail.com MS Received Through : National Conference on Advancements in Mechanical Engineering (NCAME-2015), held at Al-Falah University, Faridabad, Haryana, India on April 16, 2015 ABSTRACT In our article, we have tried to show, how to drastically improve the photovoltaic conversion eficiency and obtain eficiency over 40%. It can be achieved from improvement of multi-junction solar cells, by introducing a novel material, Indium Gallium Nitride, an ideal combination of band gaps and lattice matching. Its nano structure such as stacked quantum wells and quantum dots allow freedom in the design of band gap and lattice strain. This controlled arrangement of nano structure dots and quantum wells permits the coupling of wave- functions, which allows multiple photon absorption leading to a conversion eficiency exceeding 50 %. Its nano fabrication technology realizes high eficiency with low cost. Since such solar cells operate under a sun light concentration of 5009 to 10009, the cost of cells does not pose a problem. Multi junction solar cells laminated with multilayer of P-N junctions conigured by materials with different band gaps, show promise in absorbing as much of these photons as possible and converting the photon energy into electricity. 1. INTRODUCTION The world today depends on fossil fuels and nuclear power for generation of electricity to meet our domestic and industrial requirement of electricity .Fossil fuel is very limited and it is affecting our climate change. This pollution with climate change is a cause of anxiety all over the world. Nuclear power is full of risks. Hence world today wants a source of energy, which is cheap, sustainable and pollution free. This anxiety is driving mankind to solar research. Solar energy is green, sustainable and cheap. Efforts are being made to improve solar cells with conversion eficiency. The world wants to go from temporary to permanent source of energy. Research in solar energy is going all over the world with renewed interest Billions of dollars are being spent over research. The results are being satisfactory. The costs of solar cells with eficiency in conversion are being manufactured and used all over the world. Since 1990 global solar PV modules production has increased 500 fold from 46 mega watt to 23.5 GW in 2010 and it reached 28 GW in 2012. This growth is driven by reduced cost and higher performance of solar cells .At $3per watt for complete PV systems electricity consumption has risen to 440 billion Kwh, equivalent to over 300 GW of the capacity in U.S alone. 2. REVIEW OF RELATED DEVELOPMENT OF PV CELLS 1 st generation polycrystalline silicon (P-S) and single crystalline silicon solar cells have limited abilities to improve performance and reduced cost further. Such solar cells have a single junction and indirect band gap. Hence they require a considerable thickness of semiconductor material. Solar 2 nd generation thin ilm solar photovoltaic technology such as hydrogenated amorphous silicon, copper indium cadimium telluride (Cd Te) also use single junction cells. There is energy loss mechanism which limits the eficiency from rapid thermalisation of photo excited carriers. In this technology costs become progressive dominated by those constituent materials. The most promising approach to further reduction in cost for clean solar electricity is to increase the conversion eficiency of solar cell .The most successful method of reducing loss is to subdivide the broad solar emission spectrum in two different energy ranges (colours) and to convert each range with a cell of a well matched band gap to absorb that colour .These spectral splitting can be obtained by stacking cells on top one another. These stacked cells have already been