The main reason for the current low conversion efficiency of solar panels is the loss of "low-energy photon energy" and "high-energy photon energy", both of which limit the theoretical limit efficiency of solar panels to about 40%. The following briefly describes the improvement methods for each loss mechanism.
1. Reduce low-energy photon energy loss
Using a low band gap optoelectronic semiconductor material, for example, the band gap of typical crystalline silicon is 1.1 eV, so it can only absorb photons with a wavelength shorter than 1100 nm.
2. Reduce high energy photon energy loss
Use of high band gap optoelectronic semiconductor materials. To sum up the first two points, the combination of multi-bandgap semiconductor materials can effectively improve the utilization rate of photons with different energies.
3． Reduce absorption efficiency and reflection loss: (1) try to use semiconductor materials with high light absorption coefficients; (2) reduce the area of metal electrodes, and use transparent conductive electrodes to replace some metal electrodes; (3) increase the surface roughness of materials, Reflective layer material to reduce reflection loss caused by surface reflection.
4． Reduce open circuit voltage loss. Adjust the concentration of impurity impurities and the Fermi level of the raw materials.
5. Reduce fill factor loss: (1) use a surface passivation layer to reduce dangling bonds on the surface of the solar panel surface or the back electrode; (2) use high-purity (low-impurity) solar panel materials and better manufacturing processes to reduce devices Internal volume recombination; (3) Use good conductors as electrodes and adopt better electrode structure design to reduce series resistance.
