In the quest for more efficient and environmentally friendly solar cells, a team of researchers from the University of Cambridge, the University of Bordeaux, and the University of Crete has been exploring new materials inspired by perovskites. These scientists, led by Christos Tyrpenou and including G. Krishnamurthy Grandhi, Paola Vivo, Mikaël Kepenekian, and George Volonakis, have been investigating the potential of silver-indium halide double salts for photovoltaic applications.
The team’s research, published in the journal Advanced Energy Materials, focuses on a novel lead-free halide compound called AgInI4. Using computational methods, they designed this material by replacing bismuth with indium in a known compound, AgBiI4. Their calculations suggested that AgInI4 is chemically and dynamically stable, with a direct band gap of 1.72 eV, similar to its bismuth counterpart. However, the predicted photovoltaic performance of AgInI4 was lower under both solar and LED illumination. This reduction in performance was attributed to symmetry-forbidden optical transitions and the absence of certain electronic states derived from bismuth.
Despite extensive synthetic attempts, the researchers were unable to experimentally realize the AgInI4 phase, highlighting the challenges of stabilizing indium-based halide double salts. However, their high-throughput screening of the Ag-In-I ternary phase-space revealed several other stable and metastable compounds. These compounds fall into two structural families: tetrahedrally and octahedrally coordinated, with characteristic band gaps near 3.0 eV and 2.0 eV, respectively.
While these materials may not serve as efficient photovoltaic absorbers, their tunable band gaps and stability make them promising candidates for other optoelectronic applications, such as charge transport layers in solar cells or light-emitting diodes. The energy industry could benefit from these findings by exploring these materials for specific applications where their unique properties can be leveraged, even if they are not directly used as solar cell absorbers. The research underscores the importance of continued exploration and experimentation in the field of materials science to uncover new possibilities for sustainable energy solutions.
Source: Advanced Energy Materials
This article is based on research available at arXiv.