Synthesis-Driven Structure-Property Correlations in Metal Oxytellurides for Emerging Device Applications.

Metal oxytellurides (MOTs), a new class of mixed-anion oxychalcogenides with both O2- and Te2- ions, provide a highly tunable platform for next-generation electronic and energy devices. The structural chemistry of MOTs consists of the hard covalent oxide network with soft, polarizable telluride sublattice resulting in tunable electronic structures, adaptable coordination, and enhanced spin-orbit coupling. This Account aims to synthesize the structure-property relationships in MOTs with a unifying theme of how small deviations in anion order, composition, defect chemistry, and coordinated state can dramatically affect band structure, electron/hole transport, thermal transport, and electrochemical properties. Synthesis discussions focus on the importance of leveraging solid-state, flux-mediated, microwave-assisted, high-pressure, and topochemical transformations for phase stabilization, defect engineering, and particle/morphology control. The typical bandgap range across MOT families varies between ∼0.14 and 5.5 eV, and the highest reported thermoelectric figure of merit is ZT ≈ 1.06 for Te-substituted BiCuOTe. Structural models are analyzed with computational analysis, using density functional theory, giving insight into phase stability, defect preferences, and the consequent electronic structure evolutions. Guided by these models, descriptors, and computational predictions, select future directions are suggested for large-scale manufacture, compositional space exploration, property optimization, and commercialization of MOTs for thermoelectric, electrochemical, and optoelectronic devices.