| Abstract | Cadmium selenide(CdSe)quantumdots(QDs)weresynthesizedwithacubicshapehavingadiameterof
5.24 nm.ThepreparedCdSeQDswerecharacterizedbyusingUV–visible, Fouriertransforminfrared
(FTIR), powderX-raydiffraction(XRD)andtransmissionelectronmicroscope(TEM)measurements.The
UV–visible absorptionspectraindicatethattheopticalbandgapofCdSeQDsis 622 nmandthepeak
shiftcanmainlybeduetothequantumsizeeffects.The fluorescence decaykineticsforthesynthesized
QDs wasfollowedbytime-resolved fluorescence spectroscopy,andthespectrawereanalyzedinregard
to abi-exponentialmodeltoidentifytwolifetimevalues,thatis,shorter-lifetime1.37ns(55%)and
longer-lifetime6.58ns(45%).Theinteractionofcoumarin152(C152)andcoumarin153(C153)withQDs
surface bringsaboutfurtherconsiderablechangesintheabsorptionand fluorescence patterns.The
calculated bindingconstantfrom fluorescence quenchingmethodmatcheswellwiththatdetermined
from theabsorptionspectralchanges.Thestaticquenchingmechanismwasconfirmed bylarge
magnitude of KSV and unaltered fluorescence lifetime. |