Multicolor up-conversion emission in tellurite glasses co-doped with rare earth ions for white LED applications

Abstract

In the article the glass with molar composition of 75TeO 2 -20ZnO-5Na 2 O co-doped with Yb 3+ /Tm 3+ /Ho 3+ ions was fabricated by typical melt-quenching technique. Multicolour up-conversion emission at the wavelengths of 479 nm (blue), 546 nm (green) and 650 nm (red) corresponding to transitions 1 G 4 → 3 H 6 (Tm 3+ ), 5 F 4 → 5 I 8 (Ho 3+ ) and 5 F 5 → 5 I 8 (Ho 3+ ), respectively have been observed under infrared excitation (λ exc = 980 nm) at room temperature. Influence of molar ratio of active ions on the colour coordinates (CIE-1931) have been investigated.

Investigation of upconversion luminescence in Yb3+/Tm3+/Ho3+ triply doped antimony-germanate glass and double-clad optical fiber

“…3a). It may be associated with higher interaction between two acceptors, which lead to fast exchange of energy between Tm 3þ / Ho 3þ at lower metastable levels, thereby limiting the energy transfer processes with upconversion [23]. Analyzing the changes in shape of UC luminescence spectra in all glasses, the white point located on the CIE chromacity diagram (x ¼ 0.35, y ¼ 0.32) was achieved for glass "C" (Fig.…”

“…Emission in above range can be realised by processes with upconversion (UC) in photonic materials doped with rare-earth (RE) ions. It can be achieved in different co-doped configurations such as: Yb 3þ /Er 3þ / Tm 3þ , Yb 3þ /Tm 3þ /Tb 3þ and Yb 3þ /Tm 3þ /Ho 3þ [11e20, 23]. Moreover, reaching white point at CIE diagram via UC processes have been shown at the latest triply doped system in glasses [21], glassceramics [22], phosphors [14] and nanocrystals [24].…”