Near-infrared emission photoluminescence

The synthesis and near-infrared photoluminescence of [Os(bpy)2(3,8-diarylethynyl-l,10-phenanthroline)]2+ complexes (AEphen A = methoxy-phenyl, biphenyl, nitrophenyl) have recently been reported. These phenan-throline complexes exhibit emission in the 790-830 nm region. The nitro-phenylethynyl derivative exhibits no room temperature luminescence, presumably because of intramolecular electron transfer quenching [22],... 

It has been observed that the SWNTs suspended in a micellar solution exhibit a well-defined optical spectrum and show a bright photoluminescence in the near infrared region (Figme 22). The individual SWNT suspended in air at room temperature also shows a bright photoluminescence. The emission spectrum of the semiconducting SWNTs correlates well with the absorption spectrum in a micellar solution. The intensity of emission decreases dramatically when the isolated nanotubes start aggregating in a destabilized micellar solution. The decrease in the emission is attributed to the quenching of electrons by the metallic nanotubes when... 

Even larger probes of bent and kinked DNA are 40 A photoluminescent mineral colloidal particles of CdS [247-253]. These nanoparticles are approximately the size of proteins and can be made in a variety of sizes ( 20-100 A) and decorated with a variety of surface groups [267-279]. The emission spectrum of a nanoparticle solution depends on particle size and surface group synthetic procedures for CdS and other semiconductor nanoparticles have been developed so that the emission can be tuned throughout the visible spectrum and into the near infrared [267-279]. Moreover, the photoluminescence of CdS is sensitive to adsorbates [280-289], and thus these nanomaterials can function as luminescent chemical sensors. 

The photoluminescence of mesoporous silicon and silicon nanocrystals has received enormous study over the last 25 years. The spectroscopic nature and efficiency of various emission bands from the near-infrared to the ultraviolet are briefly reviewed, as are mechanistic studies on individual nanocrystals. Improvements in surface passivation and size control of sihcon nanocrystals have led to impressive photoluminescence quantum efficiencies in the visible range. 

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