Stabilization of TiO ₂ -based photocatalytic coating on polymer substrates with complex geometry using laser annealing

TiO₂-based photocatalytic coatings on substrates often require thermal annealing to achieve sufficient long-term stability and resistance to abrasion. This is difficult to achieve when using polymer substrates and/or other components in the system which are not stable enough for high temperature annealing. Herein, we present a method for annealing in those cases which relies on localized heating using a laser. This allows the coating the thermally anneal while at the same time protecting the substrate from higher temperatures. This method was then successfully adopted for more complex geometries, namely (half-)spherical substrates used for the so-called wireless light emitter technology.