Strong green upconversion emission in ZrO2:Yb3+–Ho3+ nanocrystals

Abstract

Structural and upconversion emission properties of ZrO2:Yb3+–Ho3+ nanocrystals were analyzed as function of Yb3+ concentration. Structural characterization shows a crystallite size up to 80 nm and tetragonal and cubic phase as the main crystalline structures. Strong green (540 nm) and weak red (670 nm) and near infrared (760 nm) emission bands were observed with 968 nm excitation. The upconversion is based on two photons absorption either by the energy transfers from Yb3+ ion or by the excited state absorption. The energy transfer efficiency was calculated to be 50% for 2 mol % of Yb3+ diminishing to less than 20% for higher concentration. The Yb3+ concentration also affects the decay time of the green emission of Ho3+ ion diminishing from 140μs for 2 mol % of Yb to 76μs for higher concentration.

Lanthanide‐Doped Nanocrystals: Strategies for Improving the Efficiency of Upconversion Emission and Their Physical Understanding

“…This is a very significant step towards the advance of materials with substantial application potential for luminescent markers, imaging, and displays. De La Rosa et al [101] reported green UC emission in ZrO 2 :Yb 3 + ,Ho 3 + nanocrystals. Strong green (l = 540 nm) and weak red (l = 670 nm) and near infrared (l = 760 nm) emission bands were obtained after excitation at l = 968 nm.…”

Efficient oxide phosphors for light upconversion; green emission from Yb3+and Ho3+co-doped Ln2BaZnO5(Ln = Y, Gd)

“…Higher upconversion efficiencies have been achieved in materials co-doped with Yb 3+ and Ho 3+ , where Yb 3+ acts as a sensitizer for Ho 3+ owing to its strong absorption around 980 nm. 28,29 Oxides materials have been reported as suitable host for Ho 3+ upconversion. 30,31 In the present work, we present results obtained on a new upconversion material, namely Ln 2 BaZnO 5 : Yb 3+ , Ho 3+ (Ln=Y,Gd).…”

Upconversion emission from amorphous Y2O3:Tm3+, Yb3+ prepared by nanosecond pulsed laser irradiation

“…Patra et al investigated the effect of crystal size and crystal phase on UC luminescence in ZrO 2 : Er 3+ nanocrystals [10]. In relevant literatures, the UC samples were synthesized by chemical methods, such as solgel [10,11], coprecipitation [12], solution combustion [13,14], and controlled hydrolysis synthesis procedures [14]. In these chemical methods, the contamination caused by chemical precursors or additives may lead to the change of the UC dynamics and affect the UC luminescence results, especially in the nanomaterials [12,13].…”