Solar batteries are gaining more popularity in everyday life, and solar energy photovoltaic conversion now looks like one of the most promising renewable power generation areas. Solar batteries, which were developed in the middle of the last century by American scientists G. Pearson, C. Fuller and D. Chapin, became widespread in spacecrafts at the very outset, and they are currently applied actively for domestic purposes. For instance, only in Germany witinin 2009–2010, the total capacity of installed domestic solar batteries was equal to 11 GWt.

Solar я concentrator photoelectric station, capacity is  1kWt, designed at the Ioffe Physical-Technical Institute under guidance of Vyacheslav Andreyev

However, solar batteries are still hard-to-get due to their high cost: the elementary item of such battery consists of expensive single-crystalline silicon. For this reason, the price per kilowatt-hour of such energy is higher than for that obtained from other sources. Solution to the problem is increasing efficiency factor of solar cells and decreasing their cost price. These problems are being tackled by a research team of the laboratory of photoelectric converters guided by Vyacheslav Andreyev at the Ioffe Physical-Technical Institute (PTI). Projects entitled “Photovoltaic conversion of solar energy” and “Development and establishment of autonomous power supply solar stations with solar spectrum splitting, solar tracking and energy storage” undertaken by these researchers were sponsored in the framework of the Federal Special-Purpose Program “Researches and developments”, and the subject matter “Development of heterostructure solar elements and phottovolcanic arrays” – in the framework of the Federal Special-Purpose Program “Scientific and educational research personnel of innovative Russia”.

STRF.ru reference:
Andreyev Vyacheslav Mikhailovich, head of laboratory of photoelectric converters, laureate of the 2007 Popov Prize of the Government of St. Petersburg and St. Petersburg Research Center at RAS, Doctor of  Engineering, Professor. A well-known expert in the solar photo power engineering field, the author of more than 160 research papers and two monographies. Laureate of the Lenin and the State Prizes. Professor, Optoelectronics Subdepartment, St. Petersburg Electrotechnical University. Currently engaged in development of high-performance cascade solar cells based on heterostructures  and  и photoconverters of concentrated solar radiation

Efficiency factor of nanoheterostructure cascade photoconverters developed by specialists of the Institute makes 36 percent, which is two or three times higher than that of silicon-based batteries. Efficiency factor increase in such photoconverters is achieved owing to sunlight splitting into several spectrum intervals and due to more effective photon energy conversion in each of them. Three-stage photoconverters consist of three photoactive areas composed of three semiconductor wafers based on alloys of chemical elements – GaInP, Ga(In)As and Ge. Short-wave, medium-wave and infrared spectrum areas are converted into energy in these semiconductors. Efficiency factor may be increased from 36% up to 45–50% if a large number of stages is applied, however, production of such multistage units is much more complicated.

Solar battery modules developed by researchers at the Physical-Technical Institute consist of photoconverters described above, which are located upon heat-removing substrates at the focal distance from mini-lens ensuring a thousandfold concentration of solar radiation. This technology enables to decrease not only active surface area of solar batteries but their cost as well.

Modules are located stepwise in the batteries developed by the researchers, upon mechatronic tracking system equipped with the sun position sensor. This enables to provide their constant sun-orientation and better sunrays collection as compared to stationary batteries, and to decrease wind load. Only 0.1 percent of generated energy is consumed by the solar station for its own power supply.

Compare: according to researchers’ estimates, a kilogram of semiconductors utilized for solar battery creation will generate as much power within 25 years as can be obtained by consuming five thousand tons of oil. This will enable to decrease the cost per Watt of these solar stations down to USD 2, which is 1.5 times lower than the existing world prices.

The project on arranging production of such solar stations was submitted at Group of Companies “Rosnanotekh”, it underwent all examinations by experts and was approved by the supervisory board. Production of solar stations invented at the Physical-Technical Institute will be organized in Stavropol with “Rosnano” support.

Interviewed by Feya Oleg, published by The Russian Nanotechnologies journal