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2、JournalofMaterialsChemistryPhoto-assistedsynthesisofhighlyfluorescentZnSe(S)quantumdotsinaqueoussolutionaaaabGuo-YuLan,Yang-WeiLin,Yu-FenHuangandHuan-TsungChang*Received16thFebruary2007,Accepted29thMarch
3、2007FirstpublishedasanAdvanceArticleontheweb23rdApril2007DOI:10.1039/b702469jThispaperdescribesthesynthesisofhighlywater-solubleandfluorescentZnSe(S)-alloyedquantumdots(QDs).Weusedzincperchloratehexahydrate,sodiumhydrogenselenideasprecursorsandmercaptopropionicacidasstabilizertosynthesizeZn
4、SeQDsinaqueoussolutionat160uCfor9h.Theas-preparedZnSeQDspossessaquantumyield(QY)of8.1%andhightrappedemission.AfterUVirradiationusinga100WHg–Xelampfor0.5h,ZnSe(S)QDshavingaQYof19.0%areformedfromZnSeQDs.However,aggregationofZnSe(S)QDsunderlongerUVirradiation(.0.5h)takesplace,leadingtoinstabil
5、ityandirreproducibility.Toovercomethis,additionalthiolcompounds(mercaptopropionicacid,mercaptosuccinicacid,11-mercaptoundecanoicacid,andthioglycolicacid)wereseparatelyaddedtoZnSeQDsolutions22duringUVirradiation.UVirradiationandoxygenacceleratethereleaseofSfromthethiolcompounds,leadingtothef
6、ormationofZnSe(S)QDs.Amongthethiolcompounds,mercaptosuccinicacidisthemostsuitableintermsofstabilityandphotoluminescenceintensity.WesuggestthatthesizeandfunctionalgroupofthethiolcompoundsplayanimportantroleindeterminingtheopticalpropertiesandstabilityofZnSe(S)QDs.Theas-preparedZnSe(S)QDsfluo
7、rescestrongly(QYupto44.0%)at407nmwithanarrowbandwidth(W1/2,25nm)whenexcitedat325nm.IntroductionQYsandstability.ZnSenanomaterialshavinggreaterbandgapsrangingfrom2.8–3.4eV(bulkZnSehavingabandgapofSemiconductornanocrystals,alsocalledquantumdots(QDs),2.7eV)areinterestingemittingmaterialsoverare
8、gionfromhavegainedconsiderableinterestsbecauseoftheirgreatUVtoblueandhavelongbeenachoiceofmaterialsforpotentialinawiderangeofapplicationssuchassensingandfabricationofbluediodelasers.22,23Havingsuchhighand1–5cellimaging.Havinggreatphotostability,highphoto
