Rare earth-doped inorganic compounds contribute mostly to the family of persistent luminescent materials due to the versatile energy levels of rare earth ions.One of the key research aims is to match the trap level stemming from the doped rare earth ion or intrinsic defects to the electronic structure of the host,and therefore thermoluminescence measurement becomes a radical technology in studying trap depth,which is one of the significant parameters that determine the properties of persistent luminescence and photostimulated luminescence.However,the results of trap depth obtained by different thermoluminescence methods are quite different so that they are not comparable.Herein,we analyzed different thermoluminescence methods,selected and improved the traditional peak position method of T_(m)/500 to be E=(-0.94Inβ+30.09)kT_(m).Only the experimental heating rate(β)is needed additionally,but the accuracy is improved greatly in most cases.This convenient and accurate method will accelerate the discovery of novel rare earth-doped materials.
Shiyou ZhangFangyi ZhaoShengqiang LiuZhen SongQuanlin Liu
In this study,we developed a single-beam optical trap-based surface-enhanced Raman scattering(SERS)optofluidic molecular fingerprint spectroscopy detection system.This system utilizes a single-beam optical trap to concentrate free silver nanoparticles(AgNPs)within an optofluidic chip,significantly enhancing SERS performance.We investigated the optical field distribution characteristics within the tapered fiber using COMSOL simulation software and established a MATLAB simulation model to validate the single-beam optical trap's effectiveness in capturing AgNPs,demonstrating the theoretical feasibility of our approach.To verify the particle capture efficacy of the system,we experimentally controlled the optical trap's on-off state to manage the capture and release of particles precisely.The experimental results indicated that the Raman signal intensity in the capture state was significantly higher than in the non-capture state,confirming that the single-beam optical trap effectively enhances the SERS detection capability of the optofluidic detection system.Furthermore,we employed Raman mapping techniques to investigate the impact of the capture area on the SERS effect,revealing that the spectral intensity of molecular fingerprints in the laser-trapping region is significantly improved.We successfully detected the Raman spectrum of crystal violet at a concentration of 10^(−9)mol/L and pesticide thiram at a concentration of 10^(−5)mol/L,further demonstrating the ability of the single-beam optical trap in enhancing the molecular fingerprint spectrum identification capability of the SERS optofluidic chips.The optical trapping SERS optofluidic detection system developed in this study,as a key component of an integrated optoelectronic sensing system,holds the potential for integration with portable high-power lasers and high-performance Raman spectrometers.This integration is expected to advance highly integrated technologies and significantly enhance the overall performance and portability of optoelectronic sensing s
Ning SunYuan GanYujie WuXing WangShen ShenYong ZhuJie Zhang
For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)materials emit light in the visible part of the spectrum;however,in recent years,there has been a growing interest in UV-emitting persistent phosphors in recent years.These materials have been tested for various applications,such as photocatalysis,sterilization,and anti-counterfeiting,among others.Here,we report on the X-ray and UV-activated UV-A long PersL of Ce^(3+)-doped Sr_(3)MgSi_(2)O_8 material.We prepared samples with varied Ce^(3+)concentrations using solid-state reaction synthesis in an ambient atmosphere and conducted a thorough investigation using photoluminescence(PL),electron paramagnetic resonance(EPR),and thermally stimulated luminescence(TSL)spectroscopy methods.Our experiments show that the PersL signal of Ce^(3+)in the 300-450 nm range can be detected for at least 16 h when samples are irradiated with X-rays or UV.The TSL analysis reveals multiple discrete charge traps in the material with activation energies between 0.5 and 1.7 eV.Further EPR measurements confirm the presence of four paramagnetic centers.The thermal stability of these centers was analyzed,and it is established that one of these centers(g_(1)=2.0056,g_(2)=1.9981,and g_(3)=1.9926)gradually decays at room temperature,which is correlated with the PersL processes.
As calls to decarbonize the steel sector increase,Chinese producers look to hydrogen to produce near zero-carbon products,while costs increase and overall demand declines.The steel sector in China is one of the biggest sources of car-bon emissions,second only to coal-fired power plants,and now its customers,both domestic and foreign,are putting pressure on the industry to become greener.As the auto industry,especially in the electric vehicle sector,booms in China,some steelmakers are switching technologies.Decarbonization of the industry is important to achieve China's dual car-bon peaking and neutrality goals.Since 2021,China has put forward a series of policies encouraging reductions in ener-gy consumption and emissions,and the adoption of new technology and more efficient processes in steelmaking.
