A Solar Cell which breaks all the records

A new world record for the conversion of sunlight into electricity using a new solar structure with four solar sub cells have been announced by the Fraunhofer Institute of Solar Energy Systems, Soitec, CEA-Leti and Helmhotlz Center Berlin. It provides 44.7% efficiency, which means 44.7% of solar spectrum's energy, from ultraviolet through to infra-red  is converted into electrical energy. This is a major breakthrough in reducing further costs of solar electricity.

It was is May 2013, when the same team announced a solar cell with efficiency of 43.6%. Currently they broke their own record with a spectacular gain of efficiency with four mini solar sub cells. These solar cells are used in concentrator photovoltaics (CPV), a technology which achieves more than twice the efficiency of conventional PV power plants. This concept originally came from the space technology, where they provided high efficiencies for the conversion of sunlight to electricity. 

"We are incredibly proud of our team which has been working now for three years on this four-junction solar cell", says Frank Dimroth, Department Head and Project Leader in the charge of this development work at Fraunhofer ISE. He also says "this four junction solar cell contains our collected expertise in this area over many years. Besides improved materials and optimization of the structure, a new procedure called water bonding plays a central role. With this technology, we are able to connect two semiconductor crystals, which otherwise cannot be grown on top of each other with high crystal quality. In this way we can produce the optimal semiconductor combination to create the highest efficiency solar cells."

External Quantum Efficiency of the four-junction solar cell. The measurement was performed at the Fraunhofer ISE CalLab.

What is a Solar Cell? Solar cell which is also called a photovoltaic cell or photo cell is an electrical device that converts the light energy directly into electricity by the photovoltaic effect. Usually this light source is the solar energy. In a typical Solar Cell Structure, light receiving on the solar cell produces both a current and a voltage to generate electric power. This process requires firstly, a material in which the absorption of light which raises an electron to a higher energy state and secondly the movement of this higher energy electron from the solar into an electric circuit. The electron then dissipates its energy in the external circuit and returns to the solar cell. In application nearly all photovoltaic energy conversion uses semiconductor materials in the form of a p-n junction. 

A basic solar cell structure