Study And Patterning Of Polymer/Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ Long Persistent Luminescence Thin Films

As two-dimensional materials, luminescent films play an important role in electron devices. Long persistent luminescence films cause wide attention for their unique afterglow properties. The bad adhesion between luminescent particles and substrates is a problem. Introducing polymer as matrix to prepare composite films can solve the problem mentioned above and also can simplify the preparation method. Patterned luminescent films can also be obtained by photolithography. The patterned luminescent films will have potential applications in new fields. In this paper, the research contents and results mainly including three parts as following:In the first part, Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺（SMS） and Ca2MgSi₂O₇:Eu²⁺,Dy³⁺（CMS） silicate long persistent luminescence particles were synthesized by sol-gel method. Results show that two kinds of particles can be respectively indexed to PDF card No.75-1736（Sr₂MgSi₂O₇） and No.35-0592（Ca2MgSi₂O₇）, which proves that both particles samples are tetragonal akermanite. The two samples respectively have emission peaks at 468 nm and 534 nm/458 nm, and the two samples can be excited by near ultraviolet and blue light. The main emission peak of SMS is different from that of CMS, which can be explained by the slight change in the crystal structure. The difference in afterglow property comes mainly from the difference in trap center concentration.In the second part, SMS particles were first modified with silane coupling agent and then PLA/SMS composite films were prepared by spin coating. Results reveal that the SMS particles after modification show well dispersibility in PLA matrix. SMS particles are randomly and uniformly dispersed in the PLA films which possess excellent optical transparency. The thickness of the composite films is about 1.24 μm and the composite films show uniform thickness and good adhesion with silicon wafer. The composite films can retain most of the lighting patterns for at least 3 min after removing the exciting light.In the third part, patterned photosensitive spin-on glass material/Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺（SOG/SMS） long persistent luminescence composite films with lines, dots and antidots on silicon wafer were fabricated by one-step photolithography. The obtained patterns are of normalized shapes and fine order and there is no crack or bubble on the surface. SMS particles are uniformly dispersed in the SOG films which possess good transparency. The thickness of the patterned composite films is about 2.70 μm and the films show uniform thickness and good adhesion with silicon wafer. The patterned composite films emit blue light benefitting from the existence of SMS particles. Both PLA/SMS and SOG/SMS composite films are presented the similar emission spectra and afterglow decay properties as SMS long persistent luminescence particles.