Crystal Growth,Structure And Properties Of Rubidium Tungstate Crystal

In recent decades,science and technology have shown exponential growth in many fields.In China,this phenomenon is particularly obvious.In just a few decades,China has developed from a poor and backward New China to today’s world manufacturing power.This explosive growth is driven by the progress and interaction of various disciplines of modern science and technology.The basis of these technological advances is material technology,which is the so-called "The emergence of new materials will drive the development of a generation of industries".In fact,the design,synthesis and growth of functional materials are prerequisites for manufacturing and manufacturing important equipment such as piezoelectric transducers and laser optical frequency converters.Inorganic functional crystals are a particularly important category of functional materials and play a vital role in the modern information age.Since W6+ belongs to both self-activated luminescent ion and do transition metal ion,the tungstate functional crystal has excellent performance in the fields of piezoelectric,nonlinear optics,and high-energy detection,and has been attracting attention in recent years.Rb22W32O107 crystal contains four WO6 octahedral groups.Due to the distortion of the Second-Order Jahn-Teller(SOJT)effect,the Rb22 W32O107 crystal has a non-centrosymmetric structure.In addition to being used as a scintillation crystal,it also has great research and application value in the field of nonlinear optics and piezoelectricity.Therefore,this article first starts with the crystal growth experiment,and then analyzes its crystal structure,basic physical and chemical properties,linear and nonlinear optical properties,and scintillation performance.The specific research content is as follows:(1)The Rb22W32O107 compound was successfully obtained by solid-phase synthesis,and by analyzing its DSC curve,it was found that Rb22W32O107 was a incongruently compound.So we decided to choose the flux method to grow it.Through flux exploration,Rb2W2O7 was selected as the flux,and small-sized crystals were obtained through spontaneous crystallization.Crystals with better quality were selected as seed crystals.By optimizing the mass-to-agent ratio and seed quality,single crystals with complete crystal shape and large size were obtained by Top-Seeded Solution Growth(TSSG).High-quality wafer with the size of about 11 ×5xl mm3 was obtained by cutting and polishing methods.(2)The crystal structure was determined and analyzed.The results showed that although we accurately weighed the reagents based on the stoichiometric ratio of Rb22W32O107,due to the presence of flux,we finally obtained the crystal chemical formula of Rb21.89W32.66O108(RWO)which structure was very similar to Rb22W32O107.We analyzed the distortion directions of the four WO6 groups in the RWO crystal,and performed quantitative calculations on the magnitude and direction of their respective local dipole moments.The(121)wafer’s rocking curve test results show that the RWO crystals grown by the flux method are of high quality,which can fully meet the needs of subsequent performance research.In addition,we also characterized and analyzed the basic physical properties and chemical stability of RWO crystals.(3)The linear and nonlinear optical properties of RWO crystals were comprehensively characterized.Based on the UV-Vis diffuse reflectance spectrum of RWO crystals,we calculated that the band gap width is 3.41 eV,which is significantly larger than most mid-and far-infrared non-linear optical crystals currently on the market.The transmission spectrum shows that the transmission range of the RWO crystal sample is 354～7100 nm,and the transmission rate at the mid-infrared transmission window(3～5 μm)is close to 80%.In addition,the frequency doubling intensity of the RWO crystal is 1.9×KDP,and the Laser Damage Threshold(LDT)is 407.6 MW/cm2.The above characterization results indicate that RWO crystals have great application potential as mid-infrared nonlinear optical crystals.(4)Part of the scintillation performance of RWO crystal was characterized.According to the photo luminescence excitation spectrum and photoluminescence spectrum of the RWO crystal,the excitation and emission wavelengths are determined to be 255 nm and 398 nm,respectively.The RWO crystal has good transmittance to the scintillation light signal.By single exponential fitting to the fluorescence decay curve,the fluorescence lifetime of RWO crystal is calculated to be 301.96 ns.The above indicators show that RWO crystal has potential application value in the field of high-energy detection as a scintillation crystal.