Photovoltaic (PV) conversion of solar energy starts to give an appreciable contribution to power generation in many countries, with more than 90% of the global PV market relying on solar cells based on crystalline silicon (c-Si). The current efficiency record of c-Si solar cells is 26.7%, against an intrinsic limit of ~29%.
The collection probability in conjunction with the generation rate in the solar cell determine the light-generated current from the solar cell. The light-generated current is the integration over the entire device thickness of the generation rate at a particular point in the device, multiplied by the collection probability at that point.
Improving the efficiency of silicon-based solar cells beyond the 29% limit requires the use of tandem structures, which potentially have a much higher (~40%) efficiency limit. Both perovskite/silicon and III-V/silicon multijunctions are of great interest in this respect.
The efficiency limits can be calculated by solving the transport equations in the assumption of optimal (Lambertian) light trapping, which can be achieved by inserting proper photonic structures in the solar cell architecture. The effects of extrinsic (bulk and surface) recombinations on the conversion efficiency are discussed.
Importance to a Solar Cell: Carriers must be able to move from their point of generation to where they can be collected. Cross section of solar cell made of high-quality material Minority carrier diffusion length (Ldiff) is LARGE. Solar cell current output (Jsc) is large. (quantum) efficiencies.
The current efficiency record of c-Si solar cells is 26.7%, against an intrinsic limit of ~29%. Current research and production trends aim at increasing the efficiency, and reducing the cost, of industrial modules.