Platinum nanoclusters in silica: Photoluminescent properties and their application for enhancing the emission of silicon nanocrystals in an integrated configuration
Abstract:We studied photoluminescence of ion implanted platinum nanoclusters embedded in silica. Pt ions were implanted at 2 MeV and the Pt nanoclusters were then nucleated by thermal treatment under either argon, air, or a reducing atmosphere of hydrogen and nitrogen. The nanoclusters showed broad photoluminescence spectra (400 to 600 nm) with a maximum intensity at 530 nm. The photoluminescence intensity of the Pt nanoclusters was sensitive to the ion fluence used during the ion implantation, and luminescence quenchi… Show more
“…As it is evident from this figure, the Pt-NCs in silica can emit light when excited at 355 nm, but not under excitation at 1064 nm. This PL emission from Pt NCs embedded in silica and sapphire has been observed before in previous works for low and high power laser excitation at 355 nm [21,37]. The PL spectra of both Pt-NCs and Au-NCs have a broadband emission from 400 to 700 nm range, but the PL peaks are 532 nm and 547 nm respectively, i.e.…”
In this work, we have studied the multi-photon excited photoluminescence from metal nanoclusters (NCs) of Au, Ag and Pt embedded in Al2O3 matrix by ion implantation. The thermal annealing process allows to obtain a system composed of larger plasmonic metal nanoparticles (NPs) surrounded by photoluminescent ultra-small metal NCs. By exciting at 1064 nm, visible emission, ranging from 450 to 800 nm, was detected. The second and fourth-order nature of the multiphoton process was verified in a power-dependent study measured for each sample below the damage threshold. Experiments show that Au and Ag NCs exhibit a four-fold enhanced multiphoton excited photoluminescence with respect to that observed for Pt NCs, which can be explained as a result of a plasmon-mediated near-field process that is of less intensity for Pt NPs. These findings provide new opportunities to combine plasmonic nanoparticles and photoluminescent nanoclusters inside a robust inorganic matrix to improve their optical properties. Plasmon-enhanced multiphoton excited photoluminescence from metal nanoclusters may find potential application as ultrasmall fluorophores in multiphoton sensing, and in the development of solar cells with highly efficient energy conversion modules.
“…As it is evident from this figure, the Pt-NCs in silica can emit light when excited at 355 nm, but not under excitation at 1064 nm. This PL emission from Pt NCs embedded in silica and sapphire has been observed before in previous works for low and high power laser excitation at 355 nm [21,37]. The PL spectra of both Pt-NCs and Au-NCs have a broadband emission from 400 to 700 nm range, but the PL peaks are 532 nm and 547 nm respectively, i.e.…”
In this work, we have studied the multi-photon excited photoluminescence from metal nanoclusters (NCs) of Au, Ag and Pt embedded in Al2O3 matrix by ion implantation. The thermal annealing process allows to obtain a system composed of larger plasmonic metal nanoparticles (NPs) surrounded by photoluminescent ultra-small metal NCs. By exciting at 1064 nm, visible emission, ranging from 450 to 800 nm, was detected. The second and fourth-order nature of the multiphoton process was verified in a power-dependent study measured for each sample below the damage threshold. Experiments show that Au and Ag NCs exhibit a four-fold enhanced multiphoton excited photoluminescence with respect to that observed for Pt NCs, which can be explained as a result of a plasmon-mediated near-field process that is of less intensity for Pt NPs. These findings provide new opportunities to combine plasmonic nanoparticles and photoluminescent nanoclusters inside a robust inorganic matrix to improve their optical properties. Plasmon-enhanced multiphoton excited photoluminescence from metal nanoclusters may find potential application as ultrasmall fluorophores in multiphoton sensing, and in the development of solar cells with highly efficient energy conversion modules.
“…Here we can notice that for Pt particles in silica or sapphire the spectrum is the same, except for the difference in intensity, with a peak centered at 530 nm and FWHM of about 140 nm. The PL emission from Pt particles in silica or sapphire comes from ultrasmall particles with size less than two nanometers 27,41 Then, the resemblances in experimental spectral PL emission for Pt particles in silica or sapphire suggest a similar size distribution for ultrasmall Pt particles in both matrices; regardless of the presence of larger plasmonic NPs as predicted by Mie fit analysis.Figure 3PL spectra of Pt, Au and Ag NCs embedded in silica ( a ) and sapphire ( b – d ) matrices. Laser excitation corresponds to 355 nm wavelength and a low pump fluence of 0.5 mJ/cm 2 .…”
Section: Results and Analisismentioning
confidence: 99%
“…Pt NPs were also synthesized in high-purity silica plates by means of a 2 MeV ion beam with a fluence of ~2.5 × 10 16 cm −2 , followed by an annealing at 600 °C for 60 minutes under RA. This thermal treatment promotes the sample damage recovery to obtain a defect free ion-implanted silica matrix 27,41 . The implanted ion fluences and the concentration depth profiles were determined by Rutherford Backscattering Spectrometry (RBS), with a 2 MeV 4 He ++ beam.…”
Section: Methodsmentioning
confidence: 99%
“…On the other hand, scarcely systematic investigation has been done to synthesize and understand the optical properties of sub-nanometer metal NCs embedded in dielectric inorganic matrices. Room temperature PL have been observed in Ag, Au and Pt NCs embedded in soda-lime silicate glasses by light synchrotron irradiation 24 , oxyfluoride and fluoroborated glasses by melt-quenching technique 25,26 and in silica matrices by ion-implantation 27–29 . Among diverse techniques used for the fabrication of metal NPs in dielectrics, ion-implantation is very attractive because it allows the possibility of synthesizing metallic NPs embedded in the near-surface region of the substrate, controlling the depth and the concentration of the NPs.…”
An intense photoluminescence emission was observed from noble metal nanoclusters (Pt, Ag or Au) embedded in sapphire plates, nucleated by MeV ion-implantation and assisted by an annealing process. In particular, the spectral photoluminescence characteristics, such as range and peak emission, were compared to the behavior observed from Pt nanoclusters embedded in a silica matrix and excited by UV irradiation. Correlation between emission energy, nanoclusters size and metal composition were analyzed by using the scaling energy relation
E
Fermi
/
N
1/3
from the spherical Jellium model. The metal nanocluster luminescent spectra were numerically simulated and correctly fitted using the bulk Fermi energy for each metal and a Gaussian nanoclusters size distribution for the samples. Our results suggest protoplasmonics photoluminescence from metal nanoclusters free of surface state or strain effects at the nanoclusters-matrix interface that can influence over their optical properties. These metal nanoclusters present very promising optical features such as bright visible photoluminescence and photostability under strong picosecond laser excitations. Besides superlinear photoluminescence from metal nanoclusters were also observed under UV high power excitation showing a quadratic dependence on the pump power fluence.
“…The use of Pt NCs has been mainly promoted with regard to their application in catalysis [15,16], and recently it has been reported that they are suitable for highly fluorescent emission systems synthesized by chemical methods [11,[17][18][19][20]. On the other hand, the synthesis and luminescent emission of embedded Pt NCs in a solid matrix have scarcely been studied [21][22][23]. Platinum NPs embedded in silica matrix by ion implantation have been previously synthesized and particular indications about the influence of annealing conditions on their growth and structure have also been reported [21].…”
A systematic study has been carried out to investigate photoluminescence and third order nonlinear ultraviolet properties exhibited by platinum nanoparticles nucleated in a high-purity silica matrix. The modification in the characteristic photoluminescence spectra of the nanocomposites, ranging between 400 and 600 nm, was obtained with the assistance of a thermal annealing process that changed the average size of the platinum nanoparticles. The influence of temperature, between 200 °C-1100 °C, during the thermal treatment of the nanostructures was analyzed. UV-vis spectroscopy studies corroborated changes in the optical absorption resonances of the ion-implanted samples after annealing, which could then be correlated with the average size of the nanoparticles. The estimated average size was also corroborated by transmision electron microscopy. For temperatures below 600 °C the system is mainly composed of ultra-small photoluminescent platinum nanoparticles. Larger platinum nanoparticles were formed at higher annealing temperatures but photoluminescence quenching was observed as the typical plasmonics response of larger metal nanoparticles started to emerge. The photoluminescence emission for samples with a particle size of less than 2 nm is enhanced approximately 12 fold with respect to the samples with a particle size in the range of 3-7 nm. Differences in the resulting photoluminescence spectra were revealed by substituting the participation of argon, hydrogen or nitrogen, as environmental gases for thermal annealing. A weak PL emission, featuring 1.5 nW at a laser excitation power of 800 μW, related to larger platinum nanoparticles was observed. New emission peaks emerging from the larger platinum nanoparticles were associated with possible hydrogen adsorption on the nanoparticles' surface. Third order nonlinear ultraviolet measurements were conducted using a time-resolved two-wave mixing method with self-diffraction at 355 nm wavelength. The observed self-diffraction decay time is less than 25 ps, regardless of the average size of the nanoparticles studied. The evolution of the self-diffracted intensities derived from temperature was also linked to the mean size of the nanoparticles in the samples. Comparative two-wave mixing evaluations also validated a modification in third order nonlinear susceptibility exhibited by annealed samples. An important role of the localized surface plasmon resonance phenomena associated with the platinum nanoparticles for photoluminescence and optical nonlinearities was identified. A proposed hypothetical electronic mechanism that may explain the exceptional optical transitions related to low-dimensional platinum systems is discussed.
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