摘要
不同于已有的采用CdTe作为模板合成CdHgTe量子点,首次采用微波辅助加热法一步合成CdHgTe/CdS核壳量子点,提出了一种简单、快速、高效的水相微波合成核壳量子点的方法。采用透射电镜、X射线衍射对CdHgTe/CdS核壳量子点的结构进行了表征,发现巯基丙酸降解释放的硫与溶液中的镉离子形成了一层厚厚的CdS结构,钝化于CdHgTe的表面,极大地提高了量子点的荧光稳定性和荧光产率。在此基础上,探讨了所合成的核壳量子点在氧化剂过氧化氢及350 W氙灯作用下的荧光稳定性,发现这种具有明亮红色荧光的量子点具有极高的稳定性,可作为探针高效应用于污水检测及生物成像领域。
A simple,rapid and highly efficient method has been developed for aqueous core-shell quantum dots( QDs) by microwave irradiation. Unlike other experiments,CdHgTe were synthesized using CdTe as a template,high quality CdHgTe/CdS QDs were prepared via the one-step method for the first time. Then CdHgTe/CdS QDs were characterized by transmission electron microscopy and powder X-ray diffraction,respectively. The results showed that the sulfide ions released from MPA during illumination coordinated with cadmium ions to form the structure of CdS,which passivated the surface of CdHgTe. This structure improved the photostability and photoluminescence quantum yields( PLQYs). On the basis,the spectral stabilities of the obtained core-shell CdHgTe/CdS QDs under environmental exposure such as oxidation and Xenon lamp irradiation were also discussed. The results illustrated that the bright red fluorescence QDs can be an alternative probe in wastewater monitoring and the imaging of living animals.
引文
[1]SHI J,KANTOFF P,WOOSTER R,et al.Cancer nanomedicine:progress,challenges and opportunities[J].Nature Reviews Cancer,2017,17:20-37.
[2]LIAN L,XIA Y,ZHANG C,et al.In situ tuning the reactivity of selenium precursor to synthesize wide range size,ultralarge-scale,and ultrastable PbSe quantum dots[J].Chemistry of Materials,2018,30(3):982-989.
[3]KONG Y,CHEN J,FANG H,et al.Highly fluorescent ribonuclease-A-encapsulated lead sulfide quantum dots for ultrasensitive fluorescence in vivo imaging in the second near-infrared window[J].Chemistry of Materials,2016,28(9):3041-3050.
[4]MAO W,GUO J,YANG W,et al.Synthesis of high-quality near-infrared-emitting CdTeSalloyed quantum dots via the hydrothermal method[J].Nanotechnology,2007,18(48):485611-485617.
[5]TANG B,YANG F,LIN Y,et al.Synthesis and characterization of wavelength tunable,watersoluble,and near-infrared-emitting CdHgTe nanorods[J].Chemistry of Materials,2007,19(6):1212-1214.
[6]CAI W,JIANG L,YI D,et al.High quality CdH-g Te nanocrystals with strong near-infrared-emission:relationship between composition and cytotoxic effects[J].Langmuir,2013,29(12):4119-4127.
[7]XIA Y,ZHU C.Use of surface-modified CdTe quantum dots as fiuorescent probes in sensing mercury(II)[J].Talanta,2008,75(1):215-221.
[8]WURTH C,GRABOLLE M,PAULI J,et al.Comparison of methods and achievable uncertainties for the relative and absolte measurement of photoluminescence quantum yields[J].Analytical Chemistry,2011,83(9):3431-3439.
[9]ZHAN H,ZHOU P,HE Z,et al.Microwave assisted aqueous synthesis of small-sized,highly luminescent CdSeS/ZnS[J].European Journal of Inorganic Chemistry,2012(15):2487-2493.
[10]GAPONIK N,TALAPIN D,ROGACH A,et al.Thiol-capping of Cd Te nanocrystals:an alternative to organometallic synthetic routes[J].The Journal of Physical Chemistry B,2002,106(29):7177-7185.
[11]LIU X,ZHOU P,LIU H,et al.Design of bright near-infrared-emitting quantum dots capped with different stabilizing ligand as ultra-sensitive probes for tumor targeting[J].Rsc Advances,2018,8(8):4221-4229.
[12]XUE B,DENG D,CAO J,et al.Synthesis of NACcapped near infrared emitting Cd Te S alloyed quantum dots and application for in vivo early tumor imaging[J].Dalton Transactions,2012,41(16):4935-4947.
[13]LIU X,ZHOU P,ZHAN H,et al.Synthesis and characterization of near infrared emitting CdH-g Te/CdS/ZnS quantum dots capped by N-acetyl-L-cysteine for in vitro and in vivo imaging[J].Rsc Advances,2017,7(48):29998-30007.
[14]ALI E,ZHENG Y,YU A,et al.Ultrasensitive Pb2+detection by glutathione capped quantum dots[J].Analytical of Chemistry,2007,79(24):9452-9458.
[15]LI H,ZHANG Y,WANG X.L-Carnitine capped quantum dots as luminescent probes for cadmium ions[J].Sensors Actuators B Chemical,2007,127(2):593-597.
[16]CHAN W,NIE S.Quantum dot bioconjugates for ultrasensitive nonisotopic detection[J].Science,1998,281(5385):2016-2018.
[17]KONESWARAN M,NARAYANASWAMY R.L-cysteine capped ZnS quantum dots based fluorescence sensor for Cu2+ion[J].Sensors Actuators B Chemical,2009,139(1):104-109.
