CdTe and Si solar cell performance comparison in a new system for solar energy conversion and storage

A new system for the effective conversion and storage of solar energy using CdTe and Si based photovoltaic solar cells and the Li-Bi2Se3 rechargable batteries was created and studied. PV Solar Cells with the different types of structure and barrier were studied (Shottky, NUS with thin insulating layer, and p-n junction), employing low-temperature and high-temperature technological cycles. The influence of the technological details upon the electrical parameters as well as the efficiency and stability of their performance were analyzed, and also the condition for improving the efficiency were found. In particular, it was established that Zn-doping of CdTe and the Al alloying to Si at 800 degreesC have a profound effect upon the PV cell characteristics. The influence of the recombination in different parts of the cell upon the cell's efficiency and the recombination dependence upon the technological features were investigated. A comparison of the performance and fabrication cost of the new systems for solar energy conversion and storage with others using conventional cells and batteries is made. It is shown that newly developed systems could provide a global efficiency close to that for traditional ones, with simpler and cheaper technology. With some modifications of the technology, we expect to get even higher efficiencies and a wider system operation temperature range. The possibilities are discussed for the creation of a hybrid energy conversion system on the basis of our cells and batteries, with an overall efficiency of transformation of solar-to-electric energy around 40%.