As a new type of inorganic ductile semiconductor, silver sulfide (α-AgS) has garnered a plethora of interests in recent years due to its promising applications in flexible electronics. However, the lack of detailed defect calculations and chemical intuition has largely hindered the optimization of material's performance. In this study, we systematically investigate the defect chemistry of extrinsic doping in α-AgS using first-principles calculations. We computationally examine a broad suite of 17 dopants and find that all aliovalent elements have extremely low doping limits (<0.002%) in α-AgS, rendering them ineffective in tuning the electron concentrations. In contrast, the isovalent elements Se and Te have relatively high doping limits, being consistent with the experimental observations. While the dopant Se or Te itself does not provide additional electrons, its introduction has a significant impact on the band gap, the band-edge position, and especially the formation energy of Ag interstitials, which effectively improve the electron concentrations by 2–3 orders of magnitudes. The size effects of Se and Te doping are responsible for the more favorable Ag interstitials in AgSSe and AgSTe with respect to pristine AgS. This work serves as a theoretical foundation for the rational design of AgS-based functional materials.

中文翻译：

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延性半导体 α-Ag2S 中外在掺杂的缺陷化学

作为一种新型无机延性半导体，硫化银（α-AgS）由于其在柔性电子领域的广阔应用前景，近年来引起了广泛的关注。然而，缺乏详细的缺陷计算和化学直觉在很大程度上阻碍了材料性能的优化。在这项研究中，我们使用第一性原理计算系统地研究了 α-AgS 中外在掺杂的缺陷化学。我们通过计算检查了 17 种掺杂剂，发现所有异价元素在 α-AgS 中的掺杂极限极低 (<0.002%)，导致它们在调节电子浓度方面无效。相比之下，等价元素Se和Te具有相对较高的掺杂极限，与实验观察结果一致。虽然掺杂剂Se或Te本身不提供额外的电子，但其引入对带隙、带边位置，尤其是Ag填隙的形成能产生显着影响，有效提高了电子浓度2~3个数量级数量级。 Se 和 Te 掺杂的尺寸效应是 AgSSe 和 AgSTe 中比原始 AgS 更有利的 Ag 间隙的原因。该工作为AgS基功能材料的合理设计提供了理论基础。