Impact of temperature and ion concentration on optical properties of Sm³⁺-doped KLaSiO₄ phosphors

Since red light stimulates plant photosynthesis, enhancing growth and flowering, the development of new red phosphors with intense emission and excellent thermal stability is crucial for improving the efficiency of artificial white LED lighting. In this study, a novel orange-red phosphor KLaSiO₄:Sm³⁺, was synthesized for the first time using a sol-gel method. This silicate phosphor exhibits stable orange-red emission in the 550-750 nm range upon excitation at 405 nm. The color temperature was determined to be 1575 K, and the excellent color purity reached 92%, owing to the most prominent emission bands at 599 nm and 648 nm. Synchrotron radiation was employed to verify Sm³⁺ optical qualities, especially in VUV -UV spectral region. Radiative transitions from ⁴G_5/2 excited state are favorably still effective even for heavily doped KLaSiO₄:Sm³⁺ phosphors. The 0.7%/K^-1 relative temperature sensitivity was acquired for ESA/GSA single band thermometric approach.