Влияние температуры апконверсионных частиц NaYF4:Er,Yb на формирование люминесценции

Saratov State University ,Elena A Sagaidachnaya,Vyacheslav I Kochubey

doi:10.18500/1817-3020-2020-20-4-306-310

Saratov State University , Elena A Sagaidachnaya + Show 1 more

Open Access

https://doi.org/10.18500/1817-3020-2020-20-4-306-310

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Abstract

The intensity of upconversion luminescence depends nonlinearly on the excitation intensity. The aim of this work is to study the effect of the temperature of NaYF4:Er,Yb upconversion particles on the dependence of the luminescence intensity on the excitation intensity. The synthesized particles were observed to have the shape of a hexagonal prism with a width of about 440 nm and a height of 445 nm. The upconversion luminescence spectra were obtained in the temperature range of 22–55° C with the excitation intensity in the range of 1.5–9.4 W/cm2. The obtained results show the green-band luminescence photons can be generated by means of two-step and three-step mechanisms: the contribution of these mechanisms depends on the temperature of the particles. As the temperature increases, the contribution of the three-stage mechanism of green luminescence excitation is enhanced.

Highlights

Upconversion particles have great potential for application in various fields due to their luminescent properties [1, 2]
Various mechanisms are involved in the generation of upconversion luminescence (UCL), such as ground-state absorption (GSA), excited-state absorption (ESA), energy transfer upconversion (ETU), cross-relaxation, non-radiative relaxation (NRR), and photon avalanche
The luminescence intensity grows non-linearly when represented on a double logarithmic scale

Summary

Introduction

Upconversion particles have great potential for application in various fields due to their luminescent properties [1, 2]. They luminesce in the visible range when excited by near-infrared laser radiation. One of the most promising upconversion particles is NaYF4 : Er,Yb [1]. Various mechanisms are involved in the generation of upconversion luminescence (UCL), such as ground-state absorption (GSA), excited-state absorption (ESA), energy transfer upconversion (ETU), cross-relaxation, non-radiative relaxation (NRR), and photon avalanche. The intensity of upconversion luminescence depends nonlinearly on the excitation intensity [2‒4] and can be expressed as follows:

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