Direct Answer: Black titanium dioxide enables functional black pigmentation by absorbing visible and near-IR light through lattice defects while remaining electrically insulating and thermally stable.
Black titanium dioxide is used as a functional pigment to achieve high optical absorption and thermal stability without introducing electrical conductivity, enabling black coloration in polymers and coatings where carbon black is unsuitable.
Black titanium dioxide is selected for functional black pigment systems where optical density is required without introducing electrical conductivity or carbon migration.
Unlike carbon black, black titanium dioxide derives its color from defect-induced sub-bandgap absorption rather than free-electron conduction, allowing stable color under heat and UV exposure.
Black titanium dioxide contains oxygen vacancies and Ti³⁺ defect states that introduce mid-gap energy levels. These states absorb visible and near-infrared photons, converting light energy into lattice vibration rather than electrical transport.
The absence of continuous conductive pathways prevents charge percolation, allowing the pigment to remain electrically insulating even at elevated loadings.
Non-Applicability: Black titanium dioxide is not suitable where electrical conductivity or EMI shielding is required.
Unknown/Unverified: Long-term optical stability under combined UV + high-humidity exposure depends on formulation and is not universally characterized.
Activation Boundary: Optical absorption weakens if reduction level is insufficient or if post-processing oxidizes Ti³⁺ back to Ti⁴⁺.
Information is derived from solid-state physics literature on defect-engineered TiO₂, optical pigment studies, and comparative pigment performance analysis.
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