New process uses light and heat to generate electricity three times more efficiently than current methods

According to the website of the Physicists' Organization, researchers at Stanford University in the United States have developed a new solar energy conversion process that can use both the sun's light and heat to generate electricity. Its efficiency in generating electricity is more than twice that of existing methods, and its production cost will likely compete with that of oil. The research results were published in the online version of Nature Materials Science on August 1.

Unlike photovoltaic technology currently used in solar panels, the new process does not lose efficiency as temperature increases, so it can operate at higher temperatures. This new process, called photon-enhanced thermionic emission (PETE), will be much more efficient than existing photovoltaic and thermal conversion technologies.

The research team led by Nick Melos, an associate professor of materials science and engineering at Stanford University, sprayed a thin layer of metallic cesium on a piece of semiconductor material, giving the material the ability to generate electricity using light and heat. The research confirmed that this new process will no longer be based on the standard photovoltaic power generation mechanism, but can produce a reaction similar to photovoltaic power generation under very high temperature conditions, and the higher the temperature, the higher the working efficiency.

Most silicon-based solar cells become inert at temperatures of 100 degrees Celsius, but PETE devices reach peak efficiency at temperatures above 200 degrees Celsius, making them best suited for use in parabolic solar concentrators. Parabolic concentrators that can reach temperatures of 800 degrees Celsius are often designed as part of solar power plant designs, so PETE devices can provide a second source of electricity for solar power plants, and by combining them with existing technologies, the cost of electricity production is expected to be minimized.

Melos calculated that the PETE process could achieve an efficiency of up to 50% when applied to solar concentrators, and 55%-60% when combined with a waste heat recycling system, which is almost three times the efficiency of existing systems.

Another advantage of the PETE system is that when used in solar concentrators, the amount of semiconductor material required to make the device is quite small, which greatly reduces the cost of solar power production.

Researchers said that the PETE process greatly enhances the feasibility of solar power generation. Even if the optimal efficiency cannot be achieved, as long as the conversion efficiency can be increased from 20% to 30%, its overall conversion efficiency will be improved by 50% on the original basis, which will greatly promote the competitiveness of the solar energy industry with the oil industry.