Intense red and green emissions from Ho3+/Yb3+ co-doped Sodium Gadolinium Molybdate Nano-phosphor: Effect of calcination temperature and Intrinsic optical bistability

Abstract We present the structural and luminescent properties of Ho3+/Yb3+ co-doped Gd0.5Na0.5MoO4 nano-phosphor synthesized through the facile co-precipitation method at different calcination temperatures. The X-ray diffraction (XRD) patterns of the samples show the pure tetragonal phase formation. The upconversion (UC) spectra recorded on excitation with 980 nm laser show the intense emission bands at 545 nm (green) and 659 nm (red) in which red emission is more intense than green emission. The intense red is suitable for bio-imaging. Under 452 nm excitation, the intense green downconversion (DC) emission is observed. It is observed that with increasing the calcination temperature, the UC/DC emission intensity increases. One of the interesting features explored is the observation of intrinsic optical bistability (IOB). This material may be applicable in various fields such as biological cell imaging, phototherapy, optical switching, display devices, solar cells, etc.