Design,Synthesis And Properties Of Near-Infrared Persistent Luminescence Materials

The unique luminescent property makes persistent luminescence materials receiving tremendous attentions in safety indication,information storage,optical anticounterfeiting,and bioimaging.At present,visible persistent luminescence materials are well developed and the typical blue as well as green persistent luminescence materials have already been successfully commercialized.On the contrary,persistent luminescence materials with longer wavelength are highly demanded due to insufficient chemical stability or persistent luminescence performance of currently reported red/near-infrared persistent luminescence materials.In addition,in the last decade,near-infrared persistent luminescence-based imaging gains much attraction due to its low irradiation damage and autofluorescence-free advantages over traditional optical imaging techniques.To this end,many efforts have been devoted to designing nearinfrared persistent luminescence materials.In this dissertation,we systematically reviewed the characteristics,properties,species,and potential applications of persistent luminescence materials.By considering the challenges and problems in the research area of near-infrared persistent luminescence materials,we firstly discovered a novel near-infrared persistent luminescence emitted ions couple and subsequently developed a series of near-infrared persistent luminescence oxynitrides;Secondly,we explored a facile synthetic method for chromium-doped zinc gallogermanate near-infrared persistent luminescence nanoparticles and also well studied the behavior of electronsmigration during red-light recharging process;Finally,a novel multifunctional platform by combination of persistent luminescence nanoparticles with metal-organic frameworks was constructed to broaden the application of persistent luminescence nanoparticles.The detailed researches are as follows:1)A series of(Ba,Sr)AlSi5O2N7:Yb near-infrared persistent luminescence materials were prepared by a two-step solid-state reaction and their optical properties were well studied.We firstly reported the phenomenon of Yb2+-Yb3+ions couple with simultaneous near-infrared persistent luminescence emitting.The suitable energy gap between the excited energy levels of Yb2+ and special structure of the host achieve the occurrence of a broad band 5d-4f transition of Yb2+(with a peak around 664 nm and a full width at half maximum of 182 nm).Specifically,(Ba0.8Sr0.2)AlSi5O2N7:Yb2+showed a PersL radiance of 4.82*10-3 mW/Sr/m2 at 1 h after the removal of 254 nm excitation source.The realization of near-infrared persistent luminescence in Yb2+was attributed to the intrinsic electron-trapped defects originating from the deviated N/O ratio in the host.Thermoluminescence results revealed that shallow traps distribution with average depth of 0.84 eV and deep traps distribution with average depth of 1.32 eV existed in the host.By using the florescence spectra,we concluded that the earinfrared persistent luminescence of Yb3+(with peak of 985 nm)was attributed to the energy transfer from Yb2+to Yb3+.2)Persistent luminescence nanoparticles with nominal composition of Zn1+xGa22xGexO4:Cr3+(x≈0.2,noted as ZGGO)were synthesized via a hydrothermal with subsequent low-temperature anneal method.ZGGO with particle size around 40-60 nm showed an excellent persistent luminescence performance and the emission peak of 699 nm originated from the 2E-4A2 transition of Cr3+.Red-light recharging induced the enhancement of persistent luminescence was observed in ZGGO.By means of thermoluminescence measurement,we concluded the enhancement of persistent luminescence was attributed to the electronic re-distribution from the deep to shallow traps after 661 nm recharging.Meanwhile,two-photos absorption or tunneling effect were also two possible ways to achieve the increased persistent luminescence after red light recharging.SiO2 coated ZGGO(note as ZGGO@SiO2)with adjustable thickness though tuning the amount of TEOS was also achieved,thus can enhance the biocompatibility of ZGGO and further modification can also be proceeded.We also demonstrated ZGGO@SiO2 with an excellent in vivo autofluorescence-free persistent luminescence imaging ability was suitable for bio-application.3)A facile surface-induced-crystallization synthetic route for the synthesis of a core-shell multifunctional nanoplatform composed of ZGGO and zeolitic imidazolate framework-8(noted as ZGGO@ZIF-8)was reported.ZGGO@ZIF-8 with particle size around 150 nm was well dispersed in water.This nanoplatform not only exhibited rechargeable autofluorescence-free near-infrared persistent luminescence imaging,but also featured ultra-high drug loading(loading content=93.2%)and acid-trigged accelerated drug release abilities.After loading drugs,ZGGO@ZIF-8-DOX showed a cumulative release amount of 32.2%in neutral environment(pH=7.4)but an increased cumulative release amount up to 47.8%in acid environment(pH=5.5)at 96 h.The persistent luminescence imaging showed that the ZGGO@ZIF-8 nanoparticles were circulated in the whole body of the mouse and enriched in the viscera.In vivo tumor therapy experiment demonstrated the tumor inhibition rate in the ZGGO@ZIF-8-DOX group reached a value of 46.8%compared with the phosphate buffer solution group.The developed ZGGO@ZIF-8 nanoparticles may open a new avenue to design multifunction-integrated and multimodal-imaging-combined nanoplatforms for the applications of tumor theranostics.Finally,we summarized and discussed the emphases of this dissertation and showcased future directions of near-infrared persistent luminescence materials.