Influence of sol–gel-derived ZnO:Al coating on luminescent properties of Y2O3:Eu3+ phosphor
- 3 Downloads
This study deposited transparent and conductive Al-doped ZnO (AZO) thin coating on the surface of Y2O3:Eu3+ phosphor particle via a sol–gel method and analyzed the influence of soaking pretreatment, sol concentration, stabilizers, and coating temperature on the microstructure and luminescent properties of AZO-coated Y2O3:Eu3+ phosphors with the aid of SEM, TEM, cathodoluminescence (CL), and photoluminescence (PL) measurements. A water soaking pretreatment was found to effectively improve the coverage and uniformity of the AZO coating, resulting in a continuous and coherent coating. This result is attributed to the presence of adsorbed water and hydroxyl groups on the Y2O3:Eu3+ particle surface after water soaking. Monoethanolamine as a stabilizer agent and higher sol concentration led to a thicker coating on the phosphors. At 800 V or lower, the CL intensity of AZO coated Y2O3:Eu3+ phosphors is significantly greater than that of the uncoated particles and increases with coating thickness. In addition, the PL emission intensity also rises with increasing coating thickness and is even higher than bare phosphors. Further increases in coating thickness beyond the optimum value led to a decrease in PL intensity. This study thus proposes that AZO coatings with sufficient thickness and surface coverage bring about in a higher electron/UV light transport and less surface defects, resulting in an improvement in emission intensity.
The deposition of AZO thin coating on Y2O3:Eu3+ phosphor was prepared by a sol-gel method.
The water soaking pretreatment effectively improves the quality of the AZO coating layer.
The AZO coating can enhance CL intensity, but the allowable applied voltage decreases.
The PL intensity rises with increasing AZO coating thickness and is even higher than bare phosphors.
KeywordsZnO:Al Surface coating Luminescence Sol–gel method Y2O3:Eu3+
The authors are grateful for the financial support from National Science Council, Taiwan, under contracts nos. NSC 93-2216-E-214-019 and NSC 94-2216-E-214-010.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 9.Chung C-C, Jean J-H (2006) Protective magnesia coating on Y2O2S:Eu phosphor powders. J Am Ceram Soc 89:2726–2730Google Scholar
- 40.Zhu M, Huang H, Gong J, Sun C, Jiang X (2007) Effect of sol satbilizer on the density of sol–gel derived ZnO fims. China Surf Eng 20:1–4Google Scholar
- 45.Li G, Lin J (2016) In: Phosphors, up conversion nano particles, quantum dots and their applications: Volume 2. Liu R-S (ed), Springer, Singapore. p 41–82.Google Scholar
- 50.Blasse G, Grabmaier BC (1994). Luminescent materials. 1994, Springer Berlin Heidelberg: Berlin, Heidelberg.Google Scholar
- 51.Zak AK, Razali R, Majid WH, Darroudi M (2011) Synthesis and characterization of a narrow size distribution of zinc oxide nanoparticles. Int J Nanomed 6:1399–1403Google Scholar