Empedocles SA, Bawendi MG
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science. 1997 Dec 19;278(5346):2114-7. doi: 10.1126/science.278.5346.2114.
The quantum-confined Stark effect in single cadmium selenide (CdSe) nanocrystallite quantum dots was studied. The electric field dependence of the single-dot spectrum is characterized by a highly polarizable excited state ( approximately 10(5) cubic angstroms, compared to typical molecular values of order 10 to 100 cubic angstroms), in the presence of randomly oriented local electric fields that change over time. These local fields result in spontaneous spectral diffusion and contribute to ensemble inhomogeneous broadening. Stark shifts of the lowest excited state more than two orders of magnitude larger than the linewidth were observed, suggesting the potential use of these dots in electro-optic modulation devices.
研究了单个硒化镉（CdSe）纳米微晶量子点中的量子限制斯塔克效应。在随时间变化的随机取向局部电场存在的情况下，单量子点光谱的电场依赖性由一个高度可极化的激发态（约10^5立方埃，与典型分子值10到100立方埃相比）来表征。这些局部场导致自发光谱扩散，并导致系综非均匀展宽。观察到最低激发态的斯塔克位移比线宽大两个数量级以上，这表明这些量子点在电光调制器件中有潜在应用。
