Optimizing photovoltaic conversion of solar energy

The importance of solar energy can never be over-emphasized. Photovoltaic conversion is the most convenient method for harnessing solar energy. The demand for solar electricity has been increasing in this power hungry world. This has challenged the existing technology for solar power and motivated researchers to find innovative solutions. High cost and high technology have always been highlighted in the context of solar photovoltaics. Due to high cost, during the initial period, solar cells could be employed only in high end applications such as space technology. For widespread use of solar cells, it is imperative to bring the cost of harnessing solar energy down to an affordable level. Efforts taken for over more than 50 years on this topic are reviewed in this paper. These include the search for low cost materials and technology, using amorphous, nanocrystalline materials or thin films, and efforts to increase the conversion efficiency. The concept of spectrum modification is the most ingenious scheme for increasing the efficiency, which ultimately can help bring down the cost.