Advertisement

Topics

Visible emission characteristics from different defects of ZnS nanocrystals.

Summary of "Visible emission characteristics from different defects of ZnS nanocrystals."

Various sized ZnS nanocrystals were prepared by treatment under H(2)S atmosphere. Resonance Raman spectra indicate that the electron-phonon coupling increases with increasing the size of ZnS. Surface and interfacial defects are formed during the treatment processes. Blue, green and orange emissions are observed for these ZnS. The blue emission (430 nm) from ZnS without treatment is attributed to surface states. ZnS sintered at 873 K displays orange luminescence (620 nm) while ZnS treated at 1173 K shows green emission (515 nm). The green luminescence is assigned to the electron transfer from sulfur vacancies to interstitial sulfur states, and the orange emission is caused by the recombination between interstitial zinc states and zinc vacancies. The lifetimes of the orange emission are much slower than that of the green luminescence and sensitively dependent on the treatment temperature. Controlling defect formation makes ZnS a potential material for photoelectrical applications.

Affiliation

State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P. O. Box 110, Dalian 116023, China. canli@dicp.ac.cn.

Journal Details

This article was published in the following journal.

Name: Physical chemistry chemical physics : PCCP
ISSN: 1463-9084
Pages: 4715-23

Links

DeepDyve research library

PubMed Articles [11154 Associated PubMed Articles listed on BioPortfolio]

Synthesis and Characterization of KMnF3:Yb/Er@KMnF3 Upconversion Luminescent Nanocrystals.

A hydrothermal method has been developed for preparation of monodispersed and flake KMnF3 upconversion luminescent nanocrystals doped with Yb3+ and Er3+. The prepared nanocystals materials were charac...

Efficiently Enhancing Visible light Photocatalytic Activity of Faceted TiO2 Nanocrystals by Synergistic Effects of Core-shell structured Au@CdS Nanoparticles and their Selective Deposition.

Integrating wide bandgap semiconductor photocatalysts with visible-light-active inorganic nanoparticles (such as Au and CdS) as sensitizers is one of the most efficient methods to improve their photoc...

Two-Dimensional Visible Spectroscopy For Studying Colloidal Semiconductor Nanocrystals.

Possibilities offered by 2D visible spectroscopy for the investigation of the properties of excitons in colloidal semiconductor nanocrystals are overviewed, with a particular focus on their ultrafast ...

Broadband near-IR emission from cubic perovskite KZnF3:Ni2+ nanocrystals embedded glass-ceramics.

Transparent KF-ZnF2-SiO2 glass-ceramics were prepared with the precipitation of KZnF3:Ni2+ nanocrystals. During excitation with a wavelength of 405 nm at room temperature, a broadband near-IR emissio...

Fluorescence Blinking and Photo-Activation of All-Inorganic Perovskite Nanocrystals, CsPbBr3 and CsPbBr2I.

Study of the emission behavior of all-inorganic perovskite nanocrystals, CsPbBr3 and CsPbBr2I, as a function of the excitation power employing fluorescence correlation spectroscopy and conventional te...

Clinical Trials [2021 Associated Clinical Trials listed on BioPortfolio]

Study of the Safety and Efficacy of Apadenoson for Detection of Myocardial Perfusion Defects Using Single-Photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging (MPI)

The purpose of this study is to see whether apadenoson is as effective as adenosine when used as a pharmacological stress agent in myocardial SPECT-Imaging to detect defects in the supply ...

Genetic and Nutritional Causes of Heart Birth Defects

Each year in the United States, thousands of babies are born with heart defects. Women who take folic acid during pregnancy have a lower risk of giving birth to infants with heart defects,...

OTIS Autoimmune Diseases in Pregnancy Project

The purpose of the OTIS Autoimmune disease in pregnancy study is to monitor planned and unplanned pregnancies exposed to certain medications, to evaluate the possible teratogenic effect of...

OTIS Autoimmune Diseases in Pregnancy Project

The purpose of the OTIS Autoimmune disease in pregnancy study is to monitor planned and unplanned pregnancies exposed to certain medications, to evaluate the possible teratogenic effect of...

Molecular Genetic Epidemiology of Three Cardiac Defects -SCOR in Pediatric Cardiovascular Disease

To identify genes involved in the pathogenesis of three types of congenital heart disease, atrial septal defects, paramembranous ventricular septal defects, and atrioventricular canal defe...

Medical and Biotech [MESH] Definitions

Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.

An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.

An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.

Tunable liquid lasers with organic compounds (i.e., dye) which have a strong absorption band, used as the active medium. During emission, the dye has to be optically excited by another light source (e.g., another laser or flash lamp). The range of the emission wavelength may be anywhere from the ultraviolet to the near infrared (i.e., from 180 to 1100nm). These lasers are operated in continuous wave and pulsed modes. (UMDNS, 2005)

A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.

Quick Search
Advertisement
 


DeepDyve research library

Searches Linking to this Article