A recent research endorsed by the Oak Ridge National Laboratory and guided by Jun Xu has created a three-dimensional nanocone-based solar cell platform that can improve the light-to-power conversion efficiency of solar photovoltaic cells by around 80%.
The technology largely overcomes the drawback of inadequate transport of charges produced by solar photons. These charges, comprising positive holes and negative electrons, often get trapped due to the flaws in bulk materials and their interfaces, thereby reducing the performance level of solar cells.
In order to get rid of the entrapment challenges and the subsequent reduction in the solar cell efficiency, Xu and his team members have produced nanocone-based solar cells and devised ways to synthesize the cells to augment the efficiency of collection charges. The three dimensional solar structures comprise n-type nanocones encircled by a p-type semiconductor.
The n-type nanocones manufactured using zinc oxide performs the role of an electron conductor and also functions as the junction framework. The p-type nanoncones, manufactured using polycrystalline cadmium telluride, functions as the main element for photon absorption and acts as a hole conductor. Researchers have achieved a high light-to-power conversion efficiency of 3.2% in comparison to the 1.8% efficiency achieved by the traditional planar structure of the same materials.
Some of the important features of the solar material include its exclusive electric field distribution, which enables efficient charge transport and efficient conversion of solar energy into electricity. The blending of nanocones by utilizing cost-effective in-house methods, and lastly the reduction of voids and defects in semiconductors, which increases the electrical and optical attributes required during conversion of solar photons to electric power. Owing to improved efficiency in charge transport, the new solar cell endures defective materials and brings down the cost involved in the manufacture of next-generation solar cells.
According to Xu, the three-dimensional structural design enables a built-in electric field distribution to convert more solar energy into electricity. Xu said that the nanocone produces an electric field of high intensity in the surrounding area of the tip junction by efficiently segregating, injecting and accumulating minority carriers, which in turn encourages a higher level of conversion efficiency than the traditional solar cells manufactured utilizing the same materials.
Source: http://www.ornl.gov/