Osovsky Ruth, Shavel Alexey, Gaponik Nikolai, Amirav Lilac, Eychmüller Alexander, Weller Horst, Lifshitz Efrat
Department of Chemistry and Solid State Institute and the Russell Berrie Nanotechnology Institute, Technion, Haifa 32000, Israel.
J Phys Chem B. 2005 Nov 3;109(43):20244-50. doi: 10.1021/jp0526795.
This paper focuses on the interactions between cysteamine-stabilized CdTe nanocrystals [CdTe(CA) NCs] and thioglycolic-acid-stabilized CdTe nanocrystals [CdTe(TGA) NCs]. These interactions were examined by the absorption, continuous, and time-resolved photoluminescence (PL) spectra of the electrostatically mixed and the covalently linked NCs assemblies comprised of the oppositely surface charged CdTe(CA) and CdTe(TGA) NCs and by a comparison with those of the corresponding pristine NCs. The CdTe(CA)-CdTe(TGA) coupling is dictated by the surfactant spacer, ranging between 0.93 and 1.14 nm and by electrostatic and covalent interactions, enabling a Förster resonance energy transfer (FRET) process among the NCs. The results revealed an excellent spectral overlap between the emission of the CdTe(TGA) NCs and the absorption of the CdTe(CA) NCs as well as a PL spectral red shift on the formation of electrostatic and covalent interactions. Furthermore, the measurements showed a lifetime ranging between 1.2 and 3 ns for the electrostatically mixed and the covalently linked assemblies, shorter than those of the pristine CdTe(CA) NCs and CdTe(TGA) NCs, both of which measured as approximately 5.5 ns. When CdTe(TGA) NCs performed as the most efficient donors, FRET rates of 10(10)-10(11) s(-1) were calculated for the electrostatically mixed NCs or covalently linked NCs.
本文聚焦于半胱胺稳定的碲化镉纳米晶体[CdTe(CA) NCs]与巯基乙酸稳定的碲化镉纳米晶体[CdTe(TGA) NCs]之间的相互作用。通过由带相反表面电荷的CdTe(CA)和CdTe(TGA) NCs组成的静电混合和共价连接的NCs组装体的吸收光谱、连续光致发光光谱和时间分辨光致发光光谱，并与相应原始NCs的光谱进行比较，对这些相互作用进行了研究。CdTe(CA)-CdTe(TGA)耦合由表面活性剂间隔基决定，其范围在0.93至1.14纳米之间，并受静电和共价相互作用影响，从而使NCs之间能够发生福斯特共振能量转移(FRET)过程。结果表明，CdTe(TGA) NCs的发射光谱与CdTe(CA) NCs的吸收光谱之间存在良好的光谱重叠，并且在形成静电和共价相互作用时，光致发光光谱发生红移。此外，测量结果显示，静电混合和共价连接的组装体的寿命在1.2至3纳秒之间，短于原始的CdTe(CA) NCs和CdTe(TGA) NCs的寿命，这两种原始NCs的寿命均约为5.5纳秒。当CdTe(TGA) NCs作为最有效的供体时，计算得出静电混合NCs或共价连接NCs的FRET速率为10(10)-10(11) s(-1)。
