ИСТИНА

Hybrid materials (HM), combining an inorganic matrix and an organic functional component (organic-inorganic HM), are used in devices for passive, active and integrated optics and photonics. The use of rare-earth metal complexes in such materials can significantly increase the luminescence efficiency due to the transfer of excitation energy to trivalent rare-earth ions from organic ligands. This energy transfer ?antenna effect? is more efficient than direct excitation of RE ions, since organic ligands have broader absorption bands than RE ions due to low-intensity of f-f transitions. Thin films were prepared by the capillary deposition technique from pre-synthesized HM powder. The initial materials were tris(8-hydroxyquinolate) ytterbium (III) and powders of CaF2, PbF2, and PbO with chemical purity better than 99.99 wt%. In order to obtain materials luminescent in the NIR region, we synthesized HM at lower temperatures by the solid-phase method. We grinded 1 wt% phosphor with an inorganic matrix and subjected to heat treatment at 200, 300, or 400 C for 2 h. The resulting powders demonstrated luminescence in the visible (400-700 nm) and NIR regions (950-1050 nm). An increase in the processing temperature resulted to the relative intensity of the NIR PL decreased, and the visible PL increased. The most stable powders with a high NIR PL intensity were obtained by heat treatment at 200 C. HM powders were dispersed in isopropanol and thoroughly mixed using an ultrasonic bath. The resulting suspension was poured into a capillary felt-tip pen (pore diameter 10 ?m). The films were prepared on glass plates, corundum ceramic surfaces, and writing paper. Upon UV excitation, the films showed PL in the visible and NIR regions, which approved a good energy transfer from the ligands to Yb3+. The research was financially supported by the Ministry of Science and Higher Education of the Russian Federation within the FSSM-2020-0005 project.