Color tunable emission through energy transfer from Yb³⁺ co-doped SrSnO₃: Ho³⁺ perovskite nano-phosphor

Abstract

First time color tunable lighting observed from Ho³⁺ and Yb³⁺ co-doped SrSnO₃ perovskite. Down-conversion and up-conversion (UC) photoluminescence emission spectra were recorded to understand the whole mechanism of energy migration between Ho³⁺ and Yb³⁺ ions. The intensity of green and red emission varies with Yb³⁺ doping which causes multicolour emissions from nano-phosphor. The intensity of UC red emission (654 nm) obtained from 1 at.% Ho³⁺ and 3 at.% Yb³⁺ co-doped nano-phosphor is nine times higher than from 1 at.% Ho³⁺ doped SrSnO₃ nano-phosphor. Enhanced brightness of 654 nm in UC process belongs in biological transparency window so that it might be a promising phosphor in the bio-medical field. Moreover, for the other Yb³⁺ co-doped nano-phosphor, Commission Internationale de l’Éclairage chromaticity co-ordinates were found near the white region and their CCT values lie in the range 4900–5100 K indicating cool white. Decay time was measured for 545 nm emission of Ho³⁺ ion found in 7.652 and 8.734 µs at 355 nm excitation. The variation in lifetime was observed in ascending order with increasing Yb³⁺ concentration which supports PL emission spectra observation that with increasing Yb³⁺ concentration, rate of transition has changed. These studies reveal that Ho³⁺ and Yb³⁺ co-doped phosphor is useful for fabrication of white LEDs.