Studying the Fluorescence Properties
of RE-Doped Nanopowders
Synthesizing Rare Earth-Doped Nanopowders
with Dopant Concentrations
How the Level of Fluorescence was
The Results that Emerged from this Experiment
Instruments and Components Used in
Nanophotonics is one of the most
exciting new fields to come out of nanotechnology. The quantum confinement
effects implicit in these very small (~ 10 nm) particles can lead
to unique optical properties. Rare-earth (RE) doped materials are
particularly of interest due to their fluorescence emissions in the
visible and infrared regions of the spectrum.
the Fluorescence Properties of RE-Doped Nanopowders
is an interest in examining the effects of particle size on the fluorescence
properties of RE-doped nanopowders as the optical characteristics
of RE ions are strongly influenced by their local bonding. Since most
photonic devices require these powders be incorporated into a host
matrix (i.e. polymer, glass, solvent), there is a need to investigate
the emission properties in different host materials. A fully-integrated
HORIBA Scientific spectroscopy system (sample chamber, Triax 550
monochromator, detectors) was employed to study the effects of different
solvents on RE-doped nanopowders.
Synthesizing Rare Earth-Doped Nanopowders with Dopant Concentrations
- a Description of the Experimental Process
Optically-active, RE-doped nanopowders containing the rare-earth ions (Er3+,Yb3+)
were synthesized with several dopant concentrations. The powders were first
analyzed out-of-solution in order to obtain the as prepared fluorescence characteristics.
This was done by placing a small amount of powder between two glass slides.
Measurements were made in reflectance mode using the SampleMax Solid State Sample
Holder (600 gr/mm grating blazed at 1.5 micron) with the sample placed approximately
45° off the entrance slit focal axis. Solid state laser diodes or a Ti:Sapphire
ring laser were used to pump the absorption bands of the RE-doped nanopowders.
Figure 1. Diagram showing an illustration of the experimental
process and the instruments used.
the Level of Fluorescence was Measured
Fluorescence was measured using HORIBA Scientific
TEcooled InGaAs and PbS detectors, with the output sent directly to a Stanford
Research SR850 lock-in amplifier (using the integrated optical chopper for beam
modulation). Subsequently, dilute solutions containing various solvents (methanol,
ethanol, and cyclohexane) were prepared for in-solution measurements. The samples
were placed in cuvettes then placed into the SampleMax rotating turret for fluorescence
The Results that
Emerged from this Experiment
The fluorescence emissions of the nanopowder/alcohol solutions, even in the
most dilute samples, were accurately measured with the constructed system. The
high resolution of the system allowed for examination of the effects of the
host matrix on the emission characteristics of the RE-doped nanopowders. Small
shifts in fluorescence peaks are normally very difficult to see with noisier
(lower intensity) signals like the dilute powder/methanol solution. However,
due to sensitivity of the HORIBA Scientific
system, small shifts were easily observed.
Figure 2. Chart showing Spectra collected with the Jobin
Yvon TE Cooled InGaAs Detector.
The HORIBA Scientific
Triax 550, coupled with the solid state laser diodes, proved
valuable to the successful observation of the effects of solvents on RE-doped
nanopowders. This high resolution fluorescence system experienced minimal noise,
allowing for effective data collection and analysis. The ability to measure
liquids, powders, bulk glasses, and thin films in a matter of minutes, was found
to drastically increase productivity. The ability to quickly interchange detectors
eliminated the need for lengthy alignment procedures when monitoring materials
which have emissions across a broad range of wavelengths.
Components Used in this Experiment
- Triax 550 Monochromator Triax 550,
- Solid State Detector Interface 1427B,
- Detector, InGaAs, TE Cooled (800 nm–1650 nm) DSS-IGA020T,
- Detector, PbS, TE Cooled (1000 nm–3000 nm) DSS-PBS020T,
- Detector, Silicon, Ambient (200 nm–1100 nm) DSS-S025A,
- SampleMax, Visible ASC-VIS,
- Sample Compartment Turret ASC-STUR,
- SampleMax Optical Rail ASC-ORAIL,
- SampleMax Solid Sample Holder ASC-SSOL,
- Chopper ACH-C,
- Lock-in Amplifier SR850,
- Cable for Silicon Detector +/- 15V CCA-LKDS,
Note: A complete set of references can be found by referring
to the original document.
Source: NIR Systems for Nanophotonics, Application Note #106
from Horiba Scientific.
For more information on this source please visit Horiba