Solar energy is an environmentally friendly and sustainable source of energy. Solar cells are made with a semiconductor substance that absorbs light and converts it into power. The amount of sunshine that can be transformed into power, on the other hand, is limited. In theory, the greatest PCE (Power Conversion Efficiency) of standard single-junction solar cells is 30 percent. This is the well-known "Shockley–Queisser Limit," which results from a trade-off between charge carrier thermalization and light absorption.
An international team of researchers put a new solar cell architecture to the test in this context. It is referred to as the Hot Carrier Multijunction Solar Cell (HCMJSC). The study would be helpful for the Solar Energy Market as it demonstrates a solar cell type that is more efficient than others.
The team built a panel with a thin hot carrier top junction series coupled to a thick cold bottom junction that made up the HCMJSC. They compared it to multijunction solar cells (MJSCs) and high-capacity solar cells (HCSCs) as reference standards.
They found that HCSC has the greatest PCE for optimal designs, followed by HCMJSC and MJSC. The HCMJSC, on the other hand, demonstrated a lower reduction in efficiency for non-optimal designs. Thus, indicating that it is more resistant to design flaws.
In addition, when compared to the HCSC, the HCMJSC had less stringent criteria for hot carrier thermalization. It was able to outperform the greatest MJSC efficiency achievable with available thermalization coefficients as a result of this. It also increased the number of materials that may be used to make HCMJSCs.
The PCEs were assessed using a model that considered numerous junctions and hot-carrier effects and a typical absorption model. The team studied how the PCE varied as tuning parameters like incident intensity, absorber thickness, bandgap, temperature, and thermalization rate were modified (which determines the rate at which the photoelectrons lose their extra kinetic energy).
Finally, the researchers assessed operating-condition resilience to ensure that design defect resilience did not come at the expense of increased susceptibility to external variables. The yearly averaged efficiencies for non-ideal solar illumination (estimated using a standard reference spectrum) were calculated, and all three designs had lower average efficiencies than their nominal values. Low-bandgap HCMJSCs were marginally more sensitive to illumination effects than high-bandgap HCMJSCs, which performed similarly to MJSCs.
Overall, this research sheds light on the elements that influence solar cell performance and the resiliencies that are significant to their applications and other technologies in the field. Thus, paving the way for more efficient solar cell design.