Luminescence and scintillation properties of La2[Si2O7]:Ce3+ functional pigment – A concept for UV-protection of coatings

• The system of La2–xCex[Si2O7] was successfully incorporated into a clearcoat matrix, as UV-protective inorganic pigment.
• Measurements of colour shift showed that the influence of the newly introduced pigment onto clearcoat remains marginal.
• Fluorescence properties of raw powders remain similar for incorporated pigment within the coating formulation.
• Our results also indicate that the compound could be further interesting as scintillator material.
• The non-centrosymmetric host lattice shows second-harmonic generation (SHG) activity.

Longterm durability is a ubiquitous aim in coatings technology. Inorganic pigments are of great interest in this field because of their high photostability and their capability of preventing photodegradation. In this work, tetragonal (space group: P41) cerium(III)-doped La2[Si2O7] has been synthesized and applied as a novel protective pigment, with regards to stability and environmental friendliness. The characterization of the La2−xCex[Si2O7] system revealed relevant photoluminescence and scintillation properties. The non-centrosymmetric host lattice shows second-harmonic generation activity. The decay time of crystalline, non-hygroscopic powders of the compound was shown to be in a competitive range (<30 ns). Furthermore, the spectral patterns of the initial synthesis product could be maintained after particle size reduction and were also detectable after incorporation into a coating formulation, while avoiding a significant colour shift in the coated films. The potential of an innovative UV-protection concept for coatings, based on La2[Si2O7]:Ce3+ could be successfully pointed out.