Mishra Neeraj Kumar, Sarkar Minarul I, Kumar Kaushal
Optical Materials & Bio-imaging Research Laboratory, Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanabad-826004, India.
Dalton Trans. 2023 Aug 22;52(33):11658-11670. doi: 10.1039/d3dt01530k.
This study investigates multimodal light emission from an Eu/Yb activated YGaO (YGG) nanophosphor synthesized using a low temperature solution combustion method. The prepared sample possesses a cubic phase and an 3̄ space group and this is confirmed with X-ray diffraction and Rietveld refinement analysis. The synthesized sample shows orange-red emission bands because of the f-f transitions of Eu under UV (393 nm) and NIR (980 nm) excitations downshifting (DS) and upconversion (UC) processes, respectively. Upon UV (393 nm) excitation of the sample, the Eu ions absorb this energy and then transfer it to a neighboring pair of Yb ions giving NIR emission (900-1100 nm) corresponding to the F → F transition of Yb. The energy transfer from a single Eu ion to a pair of Yb ions is possible because of the quantum cutting (QC) process and this energy transfer efficiency is found to increase with the increasing concentration of the Yb. The quantitative estimation of energy transfer and internal quantum cutting efficiency is determined by measuring the decay kinetics. An activation energy of 0.25 eV indicates the good thermal stability of the sample. Furthermore, samples are suitable for use in practical applications in lighting devices by combining them with the near-ultraviolet (NUV; InGaN) chip. The fabricated LED device shows stability with the driving current flow values. Studies indicate that the present nanophosphor could be useful for display devices, and in enhancing the spectral conversion efficiency of the solar cells.
本研究调查了采用低温溶液燃烧法合成的Eu/Yb激活的YGaO（YGG）纳米磷光体的多模态发光。制备的样品具有立方相和3̄空间群，这通过X射线衍射和Rietveld精修分析得到证实。合成的样品在紫外光（393 nm）和近红外光（980 nm）激发下分别由于Eu的f-f跃迁而呈现橙红色发射带，分别对应下转换（DS）和上转换（UC）过程。在对样品进行紫外光（393 nm）激发时，Eu离子吸收该能量，然后将其转移到相邻的一对Yb离子，产生对应于Yb的F → F跃迁的近红外发射（900 - 1100 nm）。由于量子剪裁（QC）过程，单个Eu离子向一对Yb离子的能量转移是可能的，并且发现这种能量转移效率随着Yb浓度的增加而提高。通过测量衰减动力学来确定能量转移和内部量子剪裁效率的定量估计。0.25 eV的活化能表明样品具有良好的热稳定性。此外，通过将样品与近紫外（NUV；InGaN）芯片结合，它们适用于照明设备的实际应用。制造的LED器件在驱动电流值下表现出稳定性。研究表明，目前的纳米磷光体可用于显示设备，并提高太阳能电池的光谱转换效率。
