Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Am Chem Soc. 2013 Apr 10;135(14):5266-9. doi: 10.1021/ja400569u. Epub 2013 Apr 2.
Discrete gold nanoparticles with diameters between 2 and 3 nm show remarkable properties including enhanced catalytic behavior and photoluminescence. However, tunability of these properties is limited by the tight size range within which they are observed. Here, we report the synthesis of discrete, bimetallic gold-copper nanoparticle alloys (diameter ≅ 2-3 nm) which display photoluminescent properties that can be tuned by changing the alloy composition. Electron microscopy, X-ray photoelectron spectroscopy, inductively coupled plasma mass spectrometry, and pulsed-field gradient stimulated echo (1)H NMR measurements show that the nanoparticles are homogeneous, discrete, and crystalline. Upon varying the composition of the nanoparticles from 0% to 100% molar ratio copper, the photoluminescence maxima shift from 947 to 1067 nm, with excitation at 360 nm. The resulting particles exhibit brightness values (molar extinction coefficient (ε) × quantum yield (Φ)) that are more than an order of magnitude larger than the brightest near-infrared-emitting lanthanide complexes and small-molecule probes evaluated under similar conditions.
直径在 2 到 3nm 之间的离散金纳米粒子表现出显著的性质，包括增强的催化行为和光致发光。然而，这些性质的可调性受到它们所观察到的紧密尺寸范围的限制。在这里，我们报告了离散的金银纳米粒子合金（直径≈2-3nm）的合成，通过改变合金组成可以调变其光致发光性质。电子显微镜、X 射线光电子能谱、电感耦合等离子体质谱和脉冲场梯度激发 echo(1)H NMR 测量表明，纳米粒子是均匀的、离散的和结晶的。当纳米粒子的组成从 0%到 100%摩尔比铜变化时，在 360nm 激发下，光致发光最大值从 947nm 移至 1067nm。所得粒子的亮度值（摩尔消光系数(ε)×量子产率(Φ)）比在类似条件下评估的最亮的近红外发射镧系元素配合物和小分子探针大一个数量级以上。
