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Quantum dots (QDs ),also called colloidal semiconductor nanocrystals,have come to the forefront of nanoscience since the turn of this century.QDs possess outstanding optical properties,such as high quantum yields,broad absorption spectra,narrow and symmetric size-tunable emission,and strong resistance to photobleaching,which make them advantageous over traditional fuorophores for biosensing applications.Using energy tunable CdSeTe/CdS/ZnS double shell QDs and gold nanorods (GNRs) as the donor and acceptor,respectively,we present a sensitive electrochemiluminescence energy transfer (ECL-ET) based immunosensor for the detection of tumor markers.Firstly a facile microwave-assisted strategy for the synthesis of green- to near-infrared-emitting CdSeTe/CdS/ZnS QDs with time- and component-tunable photoluminescence was proposed.And,on the basis of the adjustable optical properties of both CdSeTe/CdS/ZnS QDs and GNRs,excellent overlap between donor emission and acceptor absorption can be obtained to ensure effective ECL-ET quenching,thus improving the sensing sensitivity.This method represents a novel approach for versatile detection of biomolecules at low concentrations.Graphene quantum dots (GQDs),which are edge-bound nanometer-sized graphene pieces,have fascinating optical and electronic properties.They have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure,both of which are multistep tedious processes.Thus the facile aqueous synthetic route to high-quality GQDs in large scale is still imminently desired.We reported that with the assistance of microwave irradiation,greenish yellow-luminescent GQDs (gGQDs) with quantum yield (QY) up to 11.7% could be successfully prepared via cleaving graphene oxide (GO) under acid condition.The cleaving and reduction process could be accomplished simultaneously through microwave treatment without any additional reducing agent.When the gGQDs were further reduced with NaBH4,bright blue-luminescent GQDs (bGQDs) could be obtained with QY as high as 22.9%.Both GQDs showed well-known excitation-dependent PL behavior.Electrochemiluminescence (ECL) was observed from the GQDs,suggesting promising applications in ECL biosensing and imaging.Furthermore,a novel sensor for Cd2+ was proposed based on Cd2+ induced ECL quenching with cysteine (Cys) as the masking agent.