We investigated the optical properties of Ge nanocrystals surrounded by Ge3N4. The broad emission ranging from infrared to blue is due to the dependence on the crystal size and preparation methods. Here, we report high resolution Photoluminescence (PL) attributed to emission from individual Ge nanocrystals (nc-Ge) spatially resolved using micro-photoluminescence and detailed using temperature a...

Charge transfer processes with semiconductor quantum dots (QDs) have generated much interest for potential utility in energy conversion. Such configurations are generally nonbiological; however, recent studies have shown that a redox-active ruthenium(II)-phenanthroline complex (Ru2+-phen) is particularly efficient at quenching the photoluminescence (PL) of QDs, and this mechanism demonstrates g...

We have systematically studied the optical properties of ZnxCdyMg12x2ySe alloys using photoluminescence ~PL! and photoluminescence excitation. It is shown that, at low temperatures, PL is dominated by excitons localized by potential fluctuations, which become stronger with increasing Mg concentration. Such potential fluctuations are discussed in terms of a large valence band offset in Zn~Cd!Se/...

We have investigated the photoluminescence (PL) of in individual single-walled carbon nanotubes (SWNTs) placed in field-effect transistor structures to study carrier transport in the SWNT. The relation between the recombination lifetime and carrier transit time has been evaluated from the drain-field dependence of PL intensity. Time-resolved photoluminescence of SWNTs dispersed in surfactant so...

We present simultaneous near-field photoluminescence (PL) and Raman imaging of single-walled carbon nanotubes (SWNTs) with a spatial resolution better than 15 nm. Highly localized excitation is used to visualize the spatial extent of the contributing excited states. For SWNTs on glass, we typically observe highly confined PL from short segments of about 20 nm in length. The PL from micelle-enca...

This paper presents the characterization and analysis of a 16.8%-efficient 18 um silicon solar cell on steel substrate. Photoluminescence (PL) is used to monitor the solar cell’s fabrication step by step, and a correlation between PL intensity and implied open circuit voltage is established. PL images yield spatially resolved maps of key electrical parameters such as dark reverse saturation cur...

Europium (Eu) doped ZnO microsphere based nano-sheets were synthesized through hydrothermal method. Effects of different concentrations of Europium on structural and optical properties of ZnO nano-sheets were investigated in detail. Prepared un-doped and Eu-doped ZnO samples were characterized using X-Ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron micro...

The most notable obstacle of brain cancer diagnosis is the inability of delivering imaging agents across the blood-brain barrier (BBB). Recently, quantum dots (QDs) has been demonstrated as an ideal image agent for brain imaging due to their ultra-small size for crossing BBB. The plolyamidoamine dendrimers modified CdTe/CdS core/shell near-infrared (NIR) region QDs was successfully synthesized ...

In this work ZnO and Mn-doped ZnO nanocrystals were synthesized by one-step aqueous solution method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis and photoluminescence (PL) spectroscopy have been used to characterize the samples in detail. The XRD studies revealed that the ZnO and Mn-doped ZnO had wurtzite structure (hexagonal). The composi...