On roofs and on solar farms, silicon-based solar panels are one of the most efficient systems in producing electricity from sunlight, but their manufacture can be expensive and energy-intensive, in addition to being heavy and bulky. An alternative solution to low-cost thin-film solar cells also involves the caveat that they are mostly composed of toxic elements such as lead or cadmium, or contain deficient elements such as indium or tellurium.
Thus, many studies have delved into ways to improve their performance and found that the optimal thickness of these semiconductor absorbers is closely related to the absorption coefficients, so the goal would be to find an ultrathin solar cell capable of having high absorption efficiencies. efficiency and maximum performance while reducing cost, weight and production. But by aiming for an ultrathin layered cell, the problem of dealing with light-containing structures will add to the cost and complexity of the problem, because the thinner the structure, the harder it becomes to absorb energy.
To predict and test the hypotheses of the work, the authors implemented calculations of the density functional theory, which confirmed the experimental evidence. Sean Cavanaugh, one of the authors of the study from UCL and Imperial College, claims: “The importance of nuclear disorder in new inorganic solar cells is currently a hot topic of discussion in this area. Our theoretical studies of the thermodynamics and optical / electronic effects of cationic disorder in AgBiS2 have revealed both the availability of cation redistribution and the strong influence of this on optoelectronic properties. Our calculations have shown that the uniform distribution of cations will give optimal performance of solar cells in these disordered materials, which confirms the experimental discoveries as evidence of the synergy between theory and experiment. “
One of the champion devices was sent to an accredited photovoltaic (PV) calibration laboratory in Newport, USA, which confirmed an 8.85% conversion efficiency in full AM 1.5G sunlight. According to ICFO researcher and first author of the study Yongjie Wang, “Although we noticed a strong darkening of our thin films after soft annealing due to increased absorption, it was initially difficult to produce such thin devices. After taking control of the process and optimizing the complete set, including optimizing electron and hole transport layers, we finally found a highly reproducible structure for efficient solar cells with improved stability. It is very interesting to see that the 30-nm device provides such a high short-circuit current density of up to 27 mA / cm2 and an efficiency of up to 9%. “
As ICREA ICFO Professor Gerasimos Constantatos finally points out, “The devices reported in this study set a record among environmentally friendly inorganic solar cells with low-temperature and solution treatment in terms of stability, form factor and performance. Development of multicomponent systems with cationic disordered colloidal potentials. than any other photovoltaic material used to date, which makes high-performance ultra-thin photovoltaic devices highly efficient. We are delighted with the results and will continue to study to use their intriguing properties in photovoltaic and other optoelectronic devices. “