Self-Healing of Broken Bonds and Deep Gap States in Sb2Se3 and Sb2S3

Abstract Broken bonds introduced at extended defects in covalently-bonded semiconductors generally introduce deep electronic states within the gap, negatively impacting performance for applications in electronics, photochemistry, and optoelectronics. Here, it is shown that Sb2Se3 and Sb2S3, which show exceptional promise for photovoltaic and photoelectrochemical applications, exhibit a remarkable ability to self-heal broken bonds through structural reconstructions, thereby eliminating the associated deep electronic states. Unusually, these materials appear intrinsically resilient to the formation of dangling bonds at extended defects, which should be advantageous for a wide range of applications. This novel behavior is connected with particular structural and chemical features of Sb2Se3 and Sb2S3, and a number of other materials that may be expected to exhibit similar effects are identified.