Enhanced luminescence of erbium silicate: interstitial lithium directly regulates the lattice structure of erbium compound crystals

We prepared high-intensity luminescent films with a high LDP (Er³⁺ luminescence lifetime-concentration product) of 1.54 × 10¹⁹ s × cm^-3, where lithium-doped erbium silicate grains are embedded in cristobalite. The near-infrared and up-conversion luminescence intensities of erbium silicate show ∼55 and 40 times enhancement by lithium-doping, respectively. Lithium-doping directly regulates the lattice structure of erbium silicate to enhance luminescence by reducing the crystal field symmetry around erbium, meanwhile, interstitial lithium does not dilute the concentration of erbium ions. Furthermore, lithium-containing dopants promote silica to crystallize, enhancing the luminescence of erbium silicate by reducing the interface defects. These films are expected to achieve high-gain film waveguide amplifiers in chip-scale optoelectronic integration. And this method opens up possibilities to be universally applicable to erbium compounds for enhancing luminescence by directly regulating the lattice structure.