Rational design of high-conductivity α-Ag2S through first-principles guided dopant screening

Ductile α-Ag2S exhibits poor electrical conductivity owing to its low carrier concentration, which severely limits its large-scale application and development in electronic devices. Metal doping is an effective strategy for enhancing the conductivity of α-Ag2S. Here, 21 metal dopants were incorporated into the α-Ag2S lattice, and their structural stability and electronic conductivity were systematically investigated. Four key screening criteria—formation energy, lattice deformation, bandgap, and carrier concentration—were established to evaluate the dopant′s effects on the conductivity of α-Ag2S. Our findings reveal that Li (interstitial doping) and Mg (substitution doping) are the most promising dopants, significantly improving the conductivity of α-Ag2S due to their high stability, minimal lattice deformation, reduced bandgap, and substantial increase in carrier concentration (up to ∼1020 cm−3). The findings of this study provide critical insights into effective n-type doping strategies for α-Ag2S, facilitating its potential applications in electronic, thermoelectric, and optoelectronic devices.