"Babes-Bolyai" University

"Raluca Ripan" Institute for Research in Chemistry

NANOPHOSPHORS BASED ON YTTRIUM SILICATE FOR OPTOELECTRONICS


STAGE 3

Objective 1
Preparation and characterisation of NP-YSO mono-doped with rare earth (Ce, Eu, Tb) with enhanced morphostructural and luminescent characteristics

* Synthesis of NP-YSO ( effect silicon source)
* Morpho-structural characteristaion of NP-YSO by FT-IR XRD, SEM si BET
* PL characterisation of NP-YSO.

Objective 2
Synthesis of multiple activation of NP-YSO with different rare earth ions

* Preparation of Y2SiO5:Ce, Tb
* PL characterisation of modified NP-YSO

Objective 3
Physical-chemical aspects regarding the formation of YSO phosphors

* Correlation preparative conditions-morphology-structure-luminescence
* Original recipie for the synthesis of NP-YSO

Objective 4
Increasing the national and international visibility

* Dissemniation and mobilities

Objective 5
Material Base Creation

* R&D Equipment aquisition-Ultrasound synthesis station_milestone_Flexiwave


Some results and discussion:
* Effect of silicon source:


>> The effect of vinyltriethoxysilane (VTEOS) molar amount on the on the morpho-structural and luminescent characteristics of yttrium silicate phosphors was studied.

>> According to the thermal analysis it was found that the combustion of a mixture containing 1 mole of VTEOS is triggered at 2940C with a mass loss of 78.58%. The mass loss of the ashes increases from 12.2% to 16.4% along with VTEOS molar amount from 1mole to 3 mole VTEOS.

Excitation spectra (a); Emission spectra (b); Effect of VTEOS amount on emission intensities (c)


>> Under UV excitation YSO:Ce phosphors exhibit variable blue emission due to electron transitions in Ce3+ from 5d level to the ground state levels (2F5/2, 2F7/2). It was observed an enhancement of the emission intensity from 70 % to 120% along with VTEOS amount increase.

* Effect of double doping of Y2SiO5 with Ce and Tb ions:
Compositions, emission intensities and colour under 245nm UV lamp of Y2SiO5 :Ce,Tb phosphors
Phosphor FormulaRE Content
Ce(%)   Tb(%)
Emission Intensity
ICe1     ITb2     ITb3
Color eye perception, (245nm)
Y1.985Ce0.015SiO50.75-960960 Blue
Y1.985Tb0.015SiO5-0.75-109231Green
Y1.985Ce0.015 Tb0.01 SiO5 0.750.5782133166Blue white
Y1.97Ce0.015 Tb0.015 SiO50.750.75534125230Cold-White
Y1.955Ce0.015 Tb0.03 SiO50.751.5521288630Turquoise
Y1.925Ce0.015 Tb0.06 SiO50.7534165071000Green
Y1.865Ce0.015 Tb0.12 SiO50.7562577091262Intense Green
Y1.745Ce0.015 Tb0.24 SiO50.7512181 12971554Bright green
Where: 1 Emission intensity for Ce line at 400 nm (λexc=356 nm); 2 Emission intensity for Tb line at 544nm ( λexc=356 nm); 3 Emission intensity for Tb line at 544nm ( λexc=245 nm);

>> XRD results reveal that the samples are pure and that the doping ions (Tb3+ and Ce3+) are completely dissolved in the host lattice without any significant change in the crystal structure ( monoclinic X2-Y2SiO5 phase)
>> Emission characteristics of synthesized YSO:Ce3+,Tb3+ can be controlled and tuned (blue to green) using different concentrations of the luminescent dopants.

CIE chromaticity diagram of Y2 SiO5 :Ce,Tb phosphors under 245nm and 360 nm excitation

    RESULTS AND DISSEMINATION

Dissemination - Stage 3 (2015)

Published papers:

1) Effect of ultrasound treatment on the morpho-structural and luminescent characteristics of cerium doped yttrium silicate phosphors,
L. E. Muresan, A.I. Cadis, I. Perhaita, D.T. Silipas, L. Barbu Tudoran, Material Research Bulletin 68, 2015, pp. 295-301 (ISI=2.228, 2014)

2) Influence of vinyltriethoxysilane concentration on structural and luminescent characteristics of cerium doped yttrium based silicate phosphors; L. E. Muresan; A. I. Cadis; I. Perhaita; O.Ponta; O.Pana; L. Trinkler; B. Berzina; V. Korsaks, Ceramics International, 41, 2015 pp. 13179-13188 DOI: 10.1016/j.ceramint.2015.07.094 (ISI = 2.605, 2015)

Submitted papers:
Tunable Luminescence of Broadband-Excited and narrow line green emitting Y2SiO5:Ce3+, Tb3+ Phosphor
L.E. Muresan, Y. Karabulut , A.I Cadis, I. Perhaita, J. Garcia Guinea, L. Barbu Tudoran, D. Silipas, A. Canimoglu, M. Ayvacikli, N. Can, Submitted at Journal of Alloys and Compounds (ISI=2.999, 2014)

Conferences:

1) The 4th International Conference on the phisiscs of the optical materials and Devices, (ICOM 2015) 31. Aug-4 Sept 2015, Budva, Montenegru
Effect of VTEOS on the structural and luminescent characteristics of YSO:Ce Ioana Perhaita, Laura E. Muresan, Adrian I. Cadis, Oana Ponta, Laima Trinkler

2) The 4th International Conference on the phisiscs of the optical materials and Devices, (ICOM 2015) 31. Aug-4 Sept 2015, Budva, Montenegru
The effect of Ce3+ and Tb3+ doping of Y2SiO5 on morpho-structural and luminescent characteristics, Adrian I. Cadis, Laura.E. Muresan, Ioana Perhaita, Dan T. Silipas