Photoluminescence ~PL! and time-resolved photoluminescence ~TRPL! were used to study optical emissions of ultrathin InAs layers with average layer thickness ranging from 1 12 to 1 ML grown on GaAs substrates. We have found that the inhomogeneous broadening of the PL from InAs layers can be well described by the quantum-well model with InAs islands coupling to each other and being regarded as a ...

Photoluminescence (PL) spectra have been used to elucidate the band structure of graphene oxide (GO) reduced in aqueous solution. The GO reduction is measured in situ via the identification of four PL peaks produced from GO solutions with different concentrations. Using corresponding UV-visible and photoluminescence excitation (PLE) spectroscopy, and on progressing from high energy to low energ...

A new type of large area metal organic chemical vapor deposition (MOCVD) system for the growth of high quality and large size ZnO materials is introduced. Materials properties of the un-doped, nand p-doped ZnO epi-films grown on sapphire substrates by this MOCVD system are studied by various techniques, including high resolution X-ray diffraction (XRD), UV–Visible optical transmission (OT), pho...

The X-ray crystallographic characterization and solid state photoluminescence (PL) study of three new tetranuclear copper(I) clusters, [Cu4(O2CR)4], R = (3-F)C6H4 (1), (2,3,4-F)3C6H2 (2), and CF3/C6F5 (3), revealed a dependence of PL on the structural type.

The spectroscopic behavior of colloidal InP quantum dots (QDs) has been investigated as a function of the mean QD diameter (which ranged from 26 to 60 Å). Absorption spectra show up to three peaks or shoulders which reflect excited state transitions in the QDs. Global photoluminescence (PL) spectra (excitation well to the blue of the absorption onset and which consequently excites most of the Q...

Carrier transfer in vertically-coupled InAs/GaAs quantum dot (QD) pairs is investigated. Photoluminescence (PL) and PL excitation spectra measured at low temperature indicate that the PL peak intensity ratio between the emission from the two sets of QDs—i.e., the relative population of carriers between the two layers of QDs—changes with increasing excitation intensity. Temperature-dependent PL ...

We report photoluminescence (PL) measurements on self-assembled GaSb/GaAs quantum dots. As the laser excitation is increased from very low levels, the PL shows a strong red shift, and then a blue shift, such that it presents a U-shaped curve. Raising the temperature causes a large s,100 meVd blue shift of the PL, and shifts the minimum of the PL energy versus laser excitation curve to higher la...

Edge-modified graphene quantum dots (GQD-1) showed base-dependent photoluminescence (PL) responses. DBN, DBU, and Et3N gradually enhanced the PL intensity and then caused quenching, whereas quenching was not observed when pyridine and pyrimidine were used. The quenching can be explained by the photoinduced electron transfer from the anchored bases at the periphery to the emissive sites of GQD-1.

Reduced graphene oxide–carbon nanotube (RGO–CNT) hybrid materials were prepared by a simple catalyst-free route. The thermostability, photoluminescence (PL) and electrical properties of RGO–CNTs were investigated systematically. The results revealed that compared to RGO, RGO–CNTs showed multicolor PL, and higher thermostability and conductivity. The RGO–CNTs therefore have important potential a...

New two-photon sensitized multifunctional nanocomposites were designed for dual-mode imaging and real-time drug release monitoring by photoluminescence (PL) and magnetic resonance imaging (MRI). By drug loading based on coordination effect, PL signals of Eu(3+) and MRI signals of Gd(3+) can be stabilized and enhanced, respectively, which then display excellent linear decreases on drug release.