Tailoring THE luminescence properties of silver containing glasses

1. Tailoring THE luminescence properties of silvercontaining glasses Kevin Bourhis Jean-Jacques Videau, Mona Treguer, Thierry Cardinal (ICMCB-CNRS) Arnaud Royon, Lionel Canioni (CPMOH-CNRS) Workshop LasINOF, June 14th 2010

2. Introduction • Interaction between short-pulsed lasers and silver-containing glasses •  micro- and nanostructuring in 3D canbeachieved • Glass modification visible under UV (325 nm) or • blue light (405 nm) • Stability of the photo-induced structures variable • (composition, irradiation conditions…) • Examples of stability of photo-inducedstructuringwithfemtosecond lasers •  Femtosecond laser irradiation = silverreduction + heattreatment •  What affects the stability ? - silver content • - the glassymatrix • - the irradiation conditions

3. Outline Silver and gallium introduction Nature and modifications of the glassymatrix Influence of the irradiation conditions Conclusion

4. Effect of Ag and Ga in 55ZnO-40P2O5 • 55ZnO-4OP2O5 • Good system for Ag+ introduction • Hygroscopic glass  addition of Ga (reticulation) , conservation of P/Zn ratio Glass composition studied : 55 ZnO – 40 P2O5 – (5-x) Ag2O – x Ga2O3, x ? Red shift of the absorption cut-off (5d10 4d9 5s1dipolar transition Ag+ ion) withincreasing Ag/Ga 1 to 4 mol%(Ag2O) = [Ag/Ga] x 16 IR-fs structures  µm3  UV-ns structures = near-band gap, larger areas

5. Post-irradiation optical absorption Photoreduction (photographicprocess)  Formation of Agmx+ clusters Ag+ ion PHOTOSENSITIVE AGENT Luminescent probe  Agmx+ clusters • Irradiation atllaser = 355 nm • Growth of absorption bands • @ 320 nm • @ 380 nm • New Agmx+species are formedduring the irradiation • Luminescence spectra = evidences of modifications

6. Luminescence of the 55 ZnO – 40 P2O5 – (5-x) Ag2O – x Ga2O3 Red shift of the excitation band (Dl 15 nm) with Ag/Ga Modification of the glassy network Neighboring of the non-bridging O linkedwith P or Ga to beinvestigated

7. Zinc and phosphate matrix 55ZnO-40P2O5 Majority of Q2 and Q1 sites (1 or 2 NBO) Qn, n = number of bridging O Q2 = [PO4] polyhedra (long chain) Q1 = [PO4] terminal tetrahedra us & as(P-O-P), Q2 & Q1 705 cm-1 = u(P-O-P) of Q2 750 cm-1 = u(P-O-P) of Q1 Ag/Ga decreases Q1/Q2increases Hypothesis : Ag+localized on Q1 sites (chains end) Number of Q1 stable Ga addtion depolymerisation of Q2 sites Q2 + Ga2O3  2Q1

8. Luminescence after irradiation Agmx+spectra « Isolated » Ag+spectra Emission @ lexc = 325 nm; excitation @ 600 nm Emission @ lexc = 250 nm For both glasses, decrease of the « Ag+ » 365 nm band Ag-poor glass : no effect on the 280 nm band After irradiation, samespectraobtained Useless to lower the Ag/Ga ratio (2 sites, 1 ineffective, similaremissionresults)

9. Nature of the species ? Saturation phenomenon, similar to photographicprocess Consumption of the silver ions pool ? Ag+ + hu Ag0 Ag+ + Ag0  Ag2+ Ag2+ + Ag+  Ag32+… Agmx+

10. Paramagneticspecies EPR : collaboration with D. Caurant & L. Binet (ENSCP, Paris) Ag2+paramagneticcentersidentified gortho = 2.307 g // = 2.072 Triangular Ag32+ signature ? giso = 2.003 Seems to be a good tool for determining the Agmx+paramagneticspecies Concentration of speciesrelativelylow, behavior of thisspecieswith T ?

11. Comparison of the irradiations Low dosage withfs laser  similar to ns : no heat accumulation effect High dosage withfs laser : blueshifting of the luminescence to orange Controlling the dose and the temperature  tailoring of the luminescence Heattreatment : Elimination of the 380 nm excitation band Blue shifting of the emission

12. Conclusion • Effects of the silver introduction investigated : characterization of 2 luminescent sites • Effect of the gallium on the glass network discussed : • Depolymerization of the network whileincreasing the gallium content • Comparisonswiththermallytreated and fsirradiatedsamplesdone : fs irradiation = combination of athermal processes and temperature