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Hot plasmonic electrons for generation of enhanced photocurrent in gold-TiO2 nanocomposites.

Brennan LJ, Purcell-Milton F, Salmeron AS, Zhang H, Govorov AO, Fedorov AV, Gun'ko YK - Nanoscale Res Lett (2015)

Bottom Line: The composite film demonstrates a significant increase in the short circuit current (I sc) compared to unmodified TiO2 when excited at or close to the plasmon resonance of the gold nanoparticles.Photo-electrochemical investigations revealed that the increase in photocurrent is attributed to the generation and separation of plasmonically generated hot electrons at the gold/TiO2 interface and also the inter-band generation of holes in gold nanoparticles by photons with λ < 520 nm.Theoretical modelling outputs perfectly match our results obtained from photo-physical studies of the processes leading to enhanced photocurrent.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland.

ABSTRACT
In this manuscript, for the first time, we report a combination of electrophoretic and sintering approaches for introducing gold nanoparticles into nanoporous TiO2 films to generate 'hot' electrons resulting in a strong enhancement of photocurrent. The Au-TiO2 nanocomposite material was prepared by the electrophoretic deposition of gold nanoparticles into a porous nanoparticulate titanium dioxide film, creating a photoactive electrode. The composite film demonstrates a significant increase in the short circuit current (I sc) compared to unmodified TiO2 when excited at or close to the plasmon resonance of the gold nanoparticles. Then, we employed a thermal ripening process as a method of increasing the I sc of these electrodes and also as a method of tuning the plasmon peak position, with a high degree of selectivity. Photo-electrochemical investigations revealed that the increase in photocurrent is attributed to the generation and separation of plasmonically generated hot electrons at the gold/TiO2 interface and also the inter-band generation of holes in gold nanoparticles by photons with λ < 520 nm. Theoretical modelling outputs perfectly match our results obtained from photo-physical studies of the processes leading to enhanced photocurrent.

No MeSH data available.


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IPCE data and ΔIPCE spectrum analysis. A. IPCE data (recorded at 0 V) obtained for TiO2 and Au-TiO2 composite electrodes in the plasmonic domain. The inset shows the IPCE recorded from IR to UV regions of the spectrum. B. Experimental data for ΔIPCE and the comparison with the plasmon absorption peak (red curve).
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Fig4: IPCE data and ΔIPCE spectrum analysis. A. IPCE data (recorded at 0 V) obtained for TiO2 and Au-TiO2 composite electrodes in the plasmonic domain. The inset shows the IPCE recorded from IR to UV regions of the spectrum. B. Experimental data for ΔIPCE and the comparison with the plasmon absorption peak (red curve).

Mentions: The IPCE data (Figure 4A) have shown clear evidence for the generation of plasmonic photocurrent. Upon excitation at the plasmonic wavelength, the IPCE was observed to increase from 0.30% for unmodified TiO2 to 1.27% for the Au-modified system. These results are in close agreement with the photocurrent observed in the photoaction spectra (Figure 3) and also correlate closely with the UV–vis spectra obtained for the Au-TiO2 composite electrode, indicating that maximum photocurrent is obtained in the region of maximum plasmonic intensity.Figure 4


Hot plasmonic electrons for generation of enhanced photocurrent in gold-TiO2 nanocomposites.

Brennan LJ, Purcell-Milton F, Salmeron AS, Zhang H, Govorov AO, Fedorov AV, Gun'ko YK - Nanoscale Res Lett (2015)

IPCE data and ΔIPCE spectrum analysis. A. IPCE data (recorded at 0 V) obtained for TiO2 and Au-TiO2 composite electrodes in the plasmonic domain. The inset shows the IPCE recorded from IR to UV regions of the spectrum. B. Experimental data for ΔIPCE and the comparison with the plasmon absorption peak (red curve).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385105&req=5

Fig4: IPCE data and ΔIPCE spectrum analysis. A. IPCE data (recorded at 0 V) obtained for TiO2 and Au-TiO2 composite electrodes in the plasmonic domain. The inset shows the IPCE recorded from IR to UV regions of the spectrum. B. Experimental data for ΔIPCE and the comparison with the plasmon absorption peak (red curve).
Mentions: The IPCE data (Figure 4A) have shown clear evidence for the generation of plasmonic photocurrent. Upon excitation at the plasmonic wavelength, the IPCE was observed to increase from 0.30% for unmodified TiO2 to 1.27% for the Au-modified system. These results are in close agreement with the photocurrent observed in the photoaction spectra (Figure 3) and also correlate closely with the UV–vis spectra obtained for the Au-TiO2 composite electrode, indicating that maximum photocurrent is obtained in the region of maximum plasmonic intensity.Figure 4

Bottom Line: The composite film demonstrates a significant increase in the short circuit current (I sc) compared to unmodified TiO2 when excited at or close to the plasmon resonance of the gold nanoparticles.Photo-electrochemical investigations revealed that the increase in photocurrent is attributed to the generation and separation of plasmonically generated hot electrons at the gold/TiO2 interface and also the inter-band generation of holes in gold nanoparticles by photons with λ < 520 nm.Theoretical modelling outputs perfectly match our results obtained from photo-physical studies of the processes leading to enhanced photocurrent.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland.

ABSTRACT
In this manuscript, for the first time, we report a combination of electrophoretic and sintering approaches for introducing gold nanoparticles into nanoporous TiO2 films to generate 'hot' electrons resulting in a strong enhancement of photocurrent. The Au-TiO2 nanocomposite material was prepared by the electrophoretic deposition of gold nanoparticles into a porous nanoparticulate titanium dioxide film, creating a photoactive electrode. The composite film demonstrates a significant increase in the short circuit current (I sc) compared to unmodified TiO2 when excited at or close to the plasmon resonance of the gold nanoparticles. Then, we employed a thermal ripening process as a method of increasing the I sc of these electrodes and also as a method of tuning the plasmon peak position, with a high degree of selectivity. Photo-electrochemical investigations revealed that the increase in photocurrent is attributed to the generation and separation of plasmonically generated hot electrons at the gold/TiO2 interface and also the inter-band generation of holes in gold nanoparticles by photons with λ < 520 nm. Theoretical modelling outputs perfectly match our results obtained from photo-physical studies of the processes leading to enhanced photocurrent.

No MeSH data available.


Related in: MedlinePlus