Black titanium dioxide enables IR and NIR absorbing coatings by introducing oxygen-vacancy states that broaden light absorption into the near-infrared region and convert photon energy into lattice heat.
This application describes how black titanium dioxide enables infrared and near-infrared absorption by introducing oxygen-vacancy and Ti³⁺ defect states that convert absorbed radiation into heat.
Black titanium dioxide is selected for IR-absorbing coatings because its modified electronic structure extends absorption beyond the visible spectrum while maintaining chemical and thermal stability typical of TiO₂.
Unlike organic dyes or carbon black, black TiO₂ absorbs radiation primarily through defect-state electronic transitions rather than molecular vibration or broadband scattering, enabling predictable thermal conversion with improved durability.
Black TiO₂ contains oxygen vacancies and Ti³⁺ centers introduced during reduction or hydrogenation. These defects create mid-gap states that enable absorption of NIR photons (700–2500 nm).
Absorbed photon energy relaxes through phonon emission, producing localized heating rather than electron transport. This makes black TiO₂ suitable for thermal shielding and IR-blocking coatings rather than conductive applications.
Non-Applicability: Black TiO₂ is not suitable for electrically conductive coatings; it does not form percolation networks or provide charge transport.
Unknown / Unverified: Long-term defect stability under continuous high-flux IR exposure depends on processing history and has not been universally standardized.
Activation Boundary: Below a critical pigment loading, IR absorption efficiency drops sharply due to insufficient optical path length within the coating.
Conclusions are based on solid-state defect physics, TiO₂ band-structure studies, and experimental observations from IR-absorbing coating systems reported in materials science literature.
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