Colour tuning via crystalline site-selected energy transfer in a Sr2SiO4:Eu2+,Pr3+ phosphor

Abstract

Spectral adjustment based on the energy transfer process between donor–acceptor pairs has been routinely used to design luminescent materials with different colours and absorption bandwidths. This work reports an alternative way to design new luminescent materials based on a site-selected energy transfer mechanism using high precision control of dopants. The new material Sr₂SiO₄:Eu²⁺,Pr³⁺ has been successfully synthesized to show versatile emissions under site-selected excitation. We demonstrate an efficient site-selected energy transfer process from Eu²⁺ to Pr³⁺ and that dual-mode spectral control can be achieved by choosing Eu²⁺ in Sr₂SiO₄ as a yellow emission centre and Pr³⁺ as a red and near infrared emission centre. Therefore a yellow-to-orange phosphor has been realized with excitation-dependent adjustable red and near infrared emissions. The site-selected spectral adjustments and energy transfer mechanism are investigated in detail. This work suggests the design and synthesis of new materials for application in solar cells and white LED devices.