Biomedical subjects

Su-ling Zhao

Publications and source records attributed to Su-ling Zhao.

4 recordsLinked to original sources

PubMed2006

[Tm3+ concentration dependence of upconversion intensity of YLiF4: Er3+, Tm3+, Yb3+].

A series of YLiF4: Er3+ , Tm3+ , Yb3+ samples were synthesized by hydrothermal method. The concentrations of Er+ and Yb3+ were 1 mol% and 1.5 mol%, respectively. Tm3+ concentration changed from 2 to 8 mol%. The absorption of Er3+, Tm3+ and Yb3+ were observed, and the absorption of Tm3+ increased along with the increase in Tm3+ concentration. The color of upconversion luminescence of YLiF4: Er3+, Tm3+ and Yb3+ excited by 980 nm was white when Tm3+ concentration was low. The blue light resulted from the transition of 1G4-->3H6 of Tm3+, the green light from the transition of 4S(3/2)(2H(11/2))-->4I(15/2) of Er3+, and the red light from the transitions 1G4-->3F4 of Tm3+ and 4F(9/2)-->4I(15/2) of Er3+. All the upconversion intensities decreased when Tm3+ concentration increased, but the relative intensity decrease was different due to the interaction between Er3+ and Tm3+.

English Abstract↗

PubMed2006

[The influence of frequency on solid state cathodoluminescence].

Solid state cathodoluminescence (SSCL) is a new mechanism of light emission in organic-inorganic system. In the present article, we get SSCL under sinusoidal alternating-current voltage with a structure of ITO/SiO2/MEH-PPV/SiO2/Al. The spectra have two peaks: 410 and 580 nm, which obey molecular theory and band model, respectively. The temporal behaviors of both peaks in SSCL are studied with a new method of estimating lifetime in frequency domain. The intensity of the peak at 410 nm decreases as the frequency of the driving voltage increases, and the intensity of the peak at 580 nm increases as the frequency of the driving voltage increases. The difference in the dependence of light intensity on the frequency of excitation comes from the difference in the lifetime of the two peaks. The lifetime of short wavelength emission is found to be less than 5 ms while that of long wavelength emission is more than 0.05 ms.

English Abstract↗

PubMed2005

[Upconversion luminescence properties of YLiF4:Er, Tm, Yb synthesized by hydrothermal method].

YLiF4 codoped with Er3+, Tm3+ and Yb3+ ions was synthesized by hydrothermal method. The absorption spectra and upconversion spectra excited at 980 nm were investigated. Under the excitation of infrared photons, strong white emission can be obtained. According to the value of n obtained from the power law, the 484 nm blue emission, 524 and 552 nm green emission, and 665 nm red emission are all due to two photon process, while the UV emission is attributed to three photon process. The authors also analyzed the upconversion mechanism and process.

English Abstract↗

PubMed2005

[Photostimulated luminescence properties of KCl:Cu+ after UV excitation].

KCl:Cu+ powder sample was prepared with high temperature solid reaction process. After being excited by UV, the sample shows near ultraviolet blue luminescence by stimulation with 560 nm light. The research result indicates that Cu+ acts as a luminous center, and Cu+ does not change into Cu2+ by UV irradiation. So, Cu+ ions do not act as hole traps, while anion vacancies act as electron traps. Once UV excited sample is stimulated, electrons from F center combine with hole trapping center or VK center, and cause subsequent energy transfer to Cu+ ion. Then, a character emission attributed to d-s transition of Cu+ in lattice occurs.

English Abstract↗