1 research outputs found
Photoluminescent Gold–Copper Nanoparticle Alloys with Composition-Tunable Near-Infrared Emission
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 <sup>1</sup>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