Rational Design of Nonmetal Single-Atom Tellurium for Advanced Photoelectrochemical Photodetectors

Nonmetal tellurium (Te) exhibits unique advantages, such as a narrow bandgap and high carrier mobility, which facilitate its separation and transport of photogenerated carriers, thus endowing optoelectronic devices with high responsivity and detectivity. To date, the currently developed Te-related nanomaterials are dominated by Te nanosheets (NSs), Te-containing compound nanostructures, and their heterojunctions, yet the atomic utilization efficiency of Te atoms still remains unsatisfactory, far below its ultimate detection capability. In this work, Te single atoms anchored into a (nitrogen, oxygen)-doped carbon support, denoted as Te SA/(N,O)-C, were rationally designed and for the first time successfully synthesized by pyrolysis. The as-synthesized Te SA/(N,O)-C was directly utilized as the active material for the construction of a typical photoelectrochemical (PEC) photodetector. As a result of the maximum atom utilization, Te SA/(N,O)-C displays superior photocurrent density, photoresponsivity, and response/recovery time and comparable detectivity to many commonly reported Te-based nanostructures (e.g., Te NSs, Bi₂Te₃ nanoplates). Moreover, due to strong chemical formation of C-Te and O-Te bonds rather than weak Te-Te or Te-Se chemical bonds, the Te SA/(N,O)-C also exhibits outstanding PEC stability, holding great potential for practical applications.