Study On Synthesis And Properties Of Dye-Encapsulated Metal-Organic Frameworks Composites

In recent years,the research of temperature sensing and white light emission using Luminescent MOFs（LMOFs）has attracted wide attention.As a basic physical parameter,temperature plays an important role in daily life,scientific researches and technological developments.However,the contact characteristics of traditional thermometers restrict the practical applications.In order to overcome these problems and limitations,non-contact temperature measurement technologies based on luminescence have been widely concerned,which possess the advantages of fast response,high sensitivity and high spatial resolution.In particular,double emission ratio MOFs materials can be used for temperature measurement by self-calibration of intensity ratio of two independent emission peaks.This kind of double emission temperature measurement material is not easy to be interfered by external factors,which can be used as ideal temperature measurement materials.White light plays an indispensable role in daily life and technology.Traditional lighting has the disadvantages of fixed light and energy waste.Light-emitting metal-organic frameworks are considered as ideal WLED（White Light Emitting Diode）materials because of the rich light-emitting centers,good color flexibility and designability.Through reasonable selection of MOFs and dyes,this paper successfully constructed three systems of Dye@MOFs composite materials for temperature measurement and white light emission,as follows:（1）IRMOF-3 is selected as the main framework,rhodamine B（Rh B）and fluorescein sodium（FL）are used as guest luminescence molecules.Three Dye@IRMOF-3 composites,Rh B@IRMOF-3,FL@IRMOF-3 and Rh B/FL@IRMOF-3,were synthesized by in-situ encapsulation method.Rh B@IRMOF-3 and FL@IRMOF-3exhibit excellent stability,dual emission performance and outstanding temperature sensing capability.Rh B/FL@IRMOF-3 composite exhibits the emission of IRMOF-3,Rh B and FL simultaneously under the excitation of 365 nm.The fluorescence emission spectrum of Rh B/FL@IRMOF-3 covers the whole visible region and finally achieves white light emission.WLED devices made of Rh B/FL@IRMOF-3 can emit bright white light with CCT value of 5365 K and CRI value of 72.9.Rh B/FL@IRMOF-3 has potential applications in the field of white light emission.（2）In MOF is selected as the main framework,and rhodamine B,rhodamine 6G（R6G）and acridine yellow（Acf）are used as guest luminescence molecules.Three kinds of double emission Dye@In MOF composites,including Rh B@In MOF,R6G@In MOF and Acf@In MOF,were successfully synthesized by in-situ encapsulation method.The temperature sensitivity of R6G@In MOF composite is slightly higher.The maximum temperature sensitivity of Rh B@In MOF is 1.612%°C^-1（at 100°C）,Rh B@In MOF is1.106%°C^-1（at 40°C）,and Acf@In MOF is 0.702%°C^-1（at 70°C）.The experimental results show that Dye@In MOF has good cycling performance.This work extends the possibility of using MOFs based composites for ratio temperature measurement.（3）ZIF-8 is selected as the main framework.Using rhodamine B,fluorescein sodium,rhodamine 6G and acridine yellow as guest luminescence molecules,four Dye@ZIF-8composites were successfully synthesized by in-situ encapsulation method.The constructed Dye@ZIF-8 composite materials are dual emission materials,which have excellent temperature quenching performance,high temperature sensitivity and cyclic usability.In particular,these materials exhibit color changes with temperature during temperature measurement,which is more conducive to practical monitoring and analysis.