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Synthesis of Flower‐Like AuPd@SiO 2 Nanoparticles with a Broad Light Extinction for Application to Efficient Dye‐Sensitized Solar Cells
Author(s) -
Tsuji Masaharu,
Uto Keiko,
Hayashi JunIchiro,
Yoshiwara Akihiko
Publication year - 2018
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201700396
Subject(s) - materials science , alloy , nanoparticle , chemical engineering , transmission electron microscopy , transmittance , nanotechnology , photocatalysis , etching (microfabrication) , surface plasmon resonance , optoelectronics , metallurgy , chemistry , catalysis , layer (electronics) , engineering , biochemistry
Flower‐like AuPd alloy nanoparticles (NPs) are prepared by reducing a mixture of HAuCl 4 /H 2 PdCl 4 in an aqueous solution. Transmittance electron microscope (TEM), TEM‐energy dispersed X‐ray spectroscopy, and X‐ray diffraction data indicate that AuPd alloy NPs are composed of Pd rich core and Au rich shell. Crystal growth mechanism of ununiform AuPd alloy NPs is discussed in terms of oxidative etching by Cl − /O 2 . Even when AuPd alloy NPs are covered by SiO 2 shells for the use of dye‐sensitized solar cells (DSSCs), ununiform alloy structure of AuPd NPs is reserved after sintering at 450 °C. When 0.36–4.8 wt% of AuPd@SiO 2 NPs are added to TiO 2 –N719–DSSCs, the photoconversion efficiency (PCE) is enhanced by 7–38% in comparison with that obtained without addition of metallic NPs. The enhancement of PCE by the addition of AuPd@SiO 2 NPs is discussed in terms of near‐field surface plasmon resonance (SPR) effect of metallic NPs and far‐field light‐scattering effect of large TiO 2 aggregates formed by the addition of a small amount of distilled water into TiO 2 pastes. On the basis of the short‐circuit current density ( J sc ) and the open‐circuit voltage ( V oc ) changes upon the addition of AuPd@SiO 2 , the enhancement of PCE is attributed to synergy effects of far‐field scattering of large TiO 2 aggregates and near‐field SPR of AuPd@SiO 2 NPs.