What are High Efficiency Cells

High Efficiency Solar Cells are those Solar Cells whose average efficiency of converting solar energy into electricity is in general much higher than average by about 20-30%.Note common silicon solar cells have an average efficiency of between 17-19% which means that if 1000 kwh of energy is shone on this solar cell about 170-190 kwh of electricity will be produced.High Efficiency solar cells on the other hand which are made of silicon produce Efficiency of around 23-25%.Sunpower is the company which makes the highest efficiency solar panels in the world on a commercial scale.The E20 Solar Panel from Sunpower currently gives a 20% Efficiency.The Difference in Solar Panel Efficiency and Solar Cells Efficiency is due to the fact that Solar Panels have frames and other components which  reduces the Efficiency Overall of the Solar Cells which make up those Solar Modules.

Efficiency and Spectrum

Theoretically, efficiencies of over 70% could be reached by using hundreds of different layers, each one tuned to a small range of light wavelengths varying from ultraviolet to infrared. However due to difficulties in manufacturing such complicated crystals, the idea could not be put into practice. The theoretical efficiency of multi-junction solar cells is about 86.8% for an infinite number of junctions, implying that more junctions increase efficiency.Efficiency of  solar cells made from silicon normally varies from 15-24%

Efficiency Range for Commercial Silicon Solar Cells

Monocrystalline Solar Cells

Solar Cells Efficiency can vary from 18% to 24% for the normal monocrystalline silicon technology.Note solar cell manufacturers are constantly improving efficiency in order to lower their costs and get ahead in this competitive solar industry.Sunpower makes the highest efficiency crystalline solar cells on a commercial scale.Sanyo is the other company which makes the most efficient Monocrystalline cells .Suniva is challenging the two with a low cost process for making high efficiency monocrystalline solar cells.

Multicrystalline Solar Cells

Multicrystalline Solar Cells have lower efficiency and costs than monocrystalline solar cells.However they are currently the more popular though that is changing.They have an efficiency in the range of 14-17%.Some companies like JA Solar are progressing to improving the efficiency of multicrystalline solar cells to reach monocrystalline solar cells.Note Innovalight a US startup is selling an innovative material which improves the  efficiency and has tied up with a number of big Solar Cell and Panel manufacturers

Very High Efficiency Solar Cells

Very High Efficiency Solar Cells of more than 40% Efficiency are made of exotic materials and are multijunction in nature.Multjunction Solar Cells are composed of a number of layers made of different materials which can capture a greater part of the solar spectrum.These are costly to make as they are mostly done on a lab scale and require materials which are not commonly availabe.

List of Multijunction Solar Cell Manufacturers

1. Spire Semiconductor which is a small solar equipment company based in the USA has been working with US National Renewable Energy Laboratory (NREL) under an 18 month incubator project.The company has managed to  produce a triple-junction cell with 42.3 per cent conversion efficiency.
2. Emcore Corporation (NASDAQ: EMKR) is a commercial provider of Solar Cells for Spacecraft.With a sunlight-to-electricity conversion efficiency of 30%, the ZTJ solar cell is the highest performance space qualified multi-junction solar cell. Production of the multi-junctionsolar panels will take place at EMCORE’s state-of-the-art manufacturing facilities located in Albuquerque, New Mexico.
3. Amonix is the leading designer and manufacturer of concentrated photovoltaic (CPV)commercial solar power systems.. Originally developed for space-based applications,Amonix III-V multijunction cells  use three different photovoltaic materials in a single cell, they extract more energy from the range of wavelengths in sunlight.. Under concentration, this can exceed 39% in volume production (over 41% in world-record demonstrations).
4. Cyrium Technologies Inc., a designer and producer of high efficiency photovoltaic solar cells, The company is privately-held and received its first venture capital funding in 2004. Cyrium’s first generation solar cells offer efficiencies of 40 per cent or higher together with a nearly constant conversion efficiency for solar concentrations from 200 to greater than 1000 suns.
5. Spectrolab, headquartered in  California is a subsidiary of The Boeing Company that manufacturers space solar cells and panels. . The company claims its “NeXt Triple Junction” high efficiency solar cellshave a minimum average efficiency of 29.9%. In 2006 testing at the National Renewable Energy Laboratory demonstrated an efficiency of 40.7% using triple-junction solar cells developed by Spectrolab.

Sale Prices of High Efficiency Solar Cells

Solar Cells Cost

It is very difficult to buy high efficiency solar cells from top manufactures like Sunpower because they don’t sell solar cells but solar panels.However you can try and buy solar cells from Taiwanese producers like Neo Solar and others which make good quality though not the very high efficiency solar cells.Its also difficult to buy solar cells of very high efficiency fro multijunction solar cell suppliers.They anyway cost a huge amount.

Solar Cells Cost has been decreasing rapidly over the last 3-4 years as the scale has increased,Technology improved,Raw Material Polysilicon price has declined.Solar Cells which used to sell for  $2.5/watt can be bought on a commercial scale for around $1.2/watt.Note Solar Cell Costs depend on the Brand of the Company,Mono-Multi and the Shape/Size as well.