Quantum-dot solar power

One of the ten 'Emerging technologies 2007' of the MIT Technology Review

Quantum-dots are tiny crystals of semiconductors just a few nanometres wide. Due to their unique ability to interact with light, they have the potential to significantly increase the efficiency and lower the price of photovoltaic cells.

Currently, the most efficient photovoltaic cells are made out of crystalline silicon. In silicon, one photon of light frees one electron from its atomic orbit. In quantum-dots made out of particular materials, up to seven electrons are freed per photon when exposed to high-energy ultraviolet light. Moreover, quantum-dots can be produced by simple chemical reactions, while crystalline silicon wafers are relatively expensive to manufacture.

To date, however, the extra-electron effect has been observed only in isolated quantum dots. In a working quantum-dot solar cell, most electrons are swallowed up before they leave the semiconductor dot. A commercial application of this technology is presumably still many years away.

However, the potential is already real enough for Moser Baer PhotoVoltaic Ltd to acquire a significant minority stake in Stion Corporation, one of the main R&D companies studying nanostructures technology. Moser Baer PhotoVoltaic Ltd is a wholly owned subsidiary of Moser Baer India Ltd.