Multi-junction and tandem photovoltaic (PV) cells are developed to overcome the single-junction Shockley–Queisser (SQ) limit. Spectral splitting is the key to achieve high conversion efficiencies in these cells. In a typical tandem solar cell, the incident light is spectrally splitted between the upper and lower cells. Through an intelligent selection of materials, the number of layers, and the design of an efficient optical cavity, photons from the entire solar spectrum can be efficiently harvested.
Recently, Sandeep Chamoli and LI Wei from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) and collaborators GUO Chunlei and Subabsh Singh from University of Rochester, USA, proposed a wedge tandem solar cell to enhance the photon harvesting, which shows that wedge tandem can outperformed the typically used planar tandem cell. This study has been published in Advanced Simulation and Theory. Solar energy is a promising low-cost alternative to fossil fuels that has the potential to meet the ever-increasing global energy demands without any detrimental impact on the environment.
More recently, planar tandem solar cells have made a tremendous amount of success with the promise to go beyond the SQ limit. And the recent use of light trapping elements in photovoltaic devices can significantly enhance their efficiencies toward the SQ limit.
Pyramidal-shaped nano-microstructures and gradient metasurfaces are mostly used as light trapping elements in solar cells. There is, however, one major concern with nanostructured solar panels: more surface area means more surface recombination losses.
In this work, authors introduced a novel wedge-shaped tandem solar cell that itself acts as a light-trapping element. In terms of optical and electrical performance, wedge geometry outperformed planar geometry and showed 17.18 % higher efficiency.
This can be important for a number of applications including solar cell in space application where one needs lightweight and compact solar cell design with high performance.
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