Computational study on structural, elastic, mechanical and optical properties of K2AgAs ternary semiconductor compound

In this study, the structural, electronic, elastic, mechanical, and optical properties of a new Zintl phase K2AgAs ternary semiconductor compound have been investigated by the first-principles method using the plane-wave self-consistence field method. A triangulation of different exchange-correlation functionals, including local density approximation-LDA-PZ, generalized gradient approximation (GGA)-Q2D, GGA-BLYP, GGA-Perdew–Burke–Ernzerhof (PBE), GGA-PBESol, and GGA-revPBE, have been utilized to predict the properties of the material. The computed structural properties predicted that the K2AgAs compound is thermodynamically stable, and the lattice parameters are consistent with the reported experimental values. The electronic properties show that the bandgap ranges between 0.6645 and 1.1915 eV, while the conduction and valence bands are formed mainly through the hybridization of the As-2p, Ag-2p and Ag-3d, As-2p states, respectively, with other states making minimal contribution. From the calculation of elastic properties, K2AgAs were predicted to be mechanically stable. Notably, K2AgAs has been predicted to absorb light within the ultraviolet-visible regime. Owing to their good thermodynamic and mechanical stability, wide coverage of absorption in the UV-Vis region of the solar spectrum, and narrow bandgaps, K2AgAs can be formed/synthesized and applied as the active photoactive material in solar cells and other photovoltaics

Improved Light Soaking and Thermal Stability of Organic Solar Cells by Robust Interfacial Modification

The most widely used material in electron transport layers (ETL) of inverted organic solar cells (iOSCs) is zinc oxide (ZnO). However, the brittleness, inorganic nature, surface defects, and photocatalytic activity of ZnO lead to poor stability in iOSCs. Herein, the light‐soaking and thermal stability of iOSCs are substantially improved by modifying ZnO surface with polyurethane diacrylate (SAR) or urethane acrylate (OCS)‐based ultraviolet (UV) resins. The UV resins significantly reduce the energy barrier, suppress surface defects, and improve interfacial contact between ZnO ETL and the organic photoactive layer. Notably, the SAR and OCS resins mitigate the photocatalytic activity of ZnO, electrical leakage, and interfacial resistance during photoaging of OSCs. As a result, iOSCs based on modified ZnOs retain over 80% of initial efficiency under 1 sun illumination for light soaking 1000 h. Furthermore, SAR and OCS resins on ZnO surfaces form a robust crosslinked network with excellent solvent resistant properties, which result in enhanced thermal stability. These results reveal that this simple and effective approach is a promising procedure to fabricate high‐performance iOSCs