Much attention has been paid to white LEDs because of their potential applications in the illumination.The doping of rare earth ions plays an important role in the optical properties of yellow fluorescent powder.And m...Much attention has been paid to white LEDs because of their potential applications in the illumination.The doping of rare earth ions plays an important role in the optical properties of yellow fluorescent powder.And mainly aiming to raise the intensity and the luminous rate of the white LEDs and by photoluminescence and electroluminescence,the luminescence spectrum of yellow fluorescent powder bought from different places is measured.Furthermore, the luminous intensity in the normal direction and the angle distribution of half maximum power for the white LEDs packed with cylindrical Φ 5 epoxy on the same blue GaN chips are also measured under the same manufacture conditions. The results show that the yellow fluorescent powder bought from China mainland has higher optical output rate than that bought from China Taiwan and hence is more suitable to fabricate the white LEDs for practical use.展开更多
Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techn...Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techniques that can characterize excited state chirality are progressively capturing the public interest as it can provide the dynamic information for chirality generation and transfer.In this review,we focus on the theoretical background and the developmental history of femtosecond time-resolved circular dichroism spectroscopy(TRCD)techniques around the world.Additionally,we provide examples to showcase the utility of these techniques in the analysis of the dynamical molecular chemical structures,the investigation of molecular chirality generation,and the detection of electron spin dynamics in semiconductor quantum dots.展开更多
文摘Much attention has been paid to white LEDs because of their potential applications in the illumination.The doping of rare earth ions plays an important role in the optical properties of yellow fluorescent powder.And mainly aiming to raise the intensity and the luminous rate of the white LEDs and by photoluminescence and electroluminescence,the luminescence spectrum of yellow fluorescent powder bought from different places is measured.Furthermore, the luminous intensity in the normal direction and the angle distribution of half maximum power for the white LEDs packed with cylindrical Φ 5 epoxy on the same blue GaN chips are also measured under the same manufacture conditions. The results show that the yellow fluorescent powder bought from China mainland has higher optical output rate than that bought from China Taiwan and hence is more suitable to fabricate the white LEDs for practical use.
基金funded by the National Natural Science Foundation of China(No.92156024and No.92356307 to Jinquan Chen)Menghui Jia thanks the Materials Characterization Center and the Office of Laboratory and Equipment of East China Normal University for funding support(ECNUETR2023-13).
文摘Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techniques that can characterize excited state chirality are progressively capturing the public interest as it can provide the dynamic information for chirality generation and transfer.In this review,we focus on the theoretical background and the developmental history of femtosecond time-resolved circular dichroism spectroscopy(TRCD)techniques around the world.Additionally,we provide examples to showcase the utility of these techniques in the analysis of the dynamical molecular chemical structures,the investigation of molecular chirality generation,and the detection of electron spin dynamics in semiconductor quantum dots.
