This subproject is one of many research subprojects utilizing theresources provided by a Center grant funded by NIH/NCRR. The subproject andinvestigator (PI) may have received primary funding from another NIH source,and thus could be represented in other CRISP entries. The institution listed isfor the Center, which is not necessarily the institution for the investigator.Compared with fluorescent dyes, nanocrystals (NCs) have several advantages photophysical properties, such as extreme brightness, high resistance to photobleaching, high molar extinction coefficients (~10-100 times that of organic dyes), broad adsorption bands with narrow, symmetric photoluminescence spectra. Those properties are enabling the use of NCs in biological and medical areas. There are also some photophysical properties of NCs that might be disadvantageous. One of these is the property referred to as blinking or fluorescence intermittency. The fluorescence intermittency of spherical NCs has been widely studied both experimentally and theoretically; however the exact mechanism regarding the fluorescence intermittency is still a topic under theoretical and experimental investigation. Here we plan to investigate if the shape of the NCs also plays some rules in the fluorescence intermittency. Single CdSe nanorods (NRs) of several different sizes with aspect ratio ranging from 3 to 11 will be studied by fluorescence confocal microscopy. The fluorescence intensity emitted by single NRs will be collected as function of time with time resolution as short as 1 microsecond.The fluorescence on-time and off-time distribution will be calculated from the recorded intensity-time records and then be used to evaluate the fluorescence on-off behaviors of NRs samples as a function of the aspect ratio.
Showing the most recent 10 out of 128 publications
