Supporting Information
Reversibly phototunable TiO2 photonic crystal modulated by Ag nanoparticles’
plasmon resonance
Jian Liu,1,2 Mingzhu Li,1,a) Jinming Zhou,1,2 Changqing Ye,1,2 Jingxia Wang,1 Lei Jiang1
and Yanlin Song1,a)
1
Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids,
Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing,
100190, P. R. China
2
Graduate University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
a) Corresponding author. Electronic mail: ylsong@iccas.ac.cn; mingzhu@iccas.ac.cn.
Fax: (+86) 10-6252 9284.
Experimental section:
Synthesis of TiO2 PC. In a typical synthesis, 20 g of TBT was dissolved in 20 g of ethyl alcohol
with stirring for 1 hour. Then 2.12 g of acetic acid, 4.06 g of hydrochloric acid and 7 g of ethyl
alcohol were mixed homogenously and followed with adding dropwize into the above solution and
stirred for another 3 hours. The obtained yellow transparent solution was allowed to undergo
hydrolysis reaction at room temperature overnight. Infiltration was performed by placing the
templates in precursor solution at 45 °C for 10 minutes. The alkoxide precursor infiltrated the voids
of template through capillary force and hydrolyzed there. Nanocrystalline films were prepared on
as-cleaned glass slides by spin-coating of alkoxide precursor sol at 3000 rpm for 4 times. All the
films were dried in an oven at 80 °C overnight followed by calcination at 450 °C for 4 hours at a
ramp rate of 1 °C /min.
Photodeposition of Ag nanoparticles. The resulting TiO2 photonic crystal films were soaked in 1M
AgNO3 aqueous solutions for 3 minutes and rinsed with pure water. After drying, the film was
irradiated with ultraviolet light (10 mWcm-2) for 15 minutes in air at room temperature by using
commercial UV lamps to reduce the adsorbed Ag+ to Ag nanoparticles.
Characterization. Reflectance measurements were measured using a USB 2000 Fiber Ocean Optics
Spectrometer. SEM images were taken by JEOL FE-SEM 6700F microscopy operating at 3.0 kV.
TEM images were obtained on a JEOL JEM-2010 transmission electron microscope operating at 200
kV. Samples obtained by scratching the films from the substrate for TEM measurements were
dispersed in ethanol. Carbon coated copper grids were used as the sample holder. X-ray
photoelectron spectroscopy data were obtained with an ESCALab220i-XL electron spectrometer
from VG Scientific using 300W Al Kα radiation. The base pressure was about 3×10-9 mbar. The
binding energies were referenced to the C1s line at 284.8 eV from adventitious carbon.
Figures:
FIG. S1. (a) SEM image of i-TiO2 PC; (b) TEM image of Ag-TiO2 PC.
FIG. S2. XPS survey of Ag-TiO2 PC. 1) Ag-TiO2 PC; 2) Ag-TiO2 PC upon visible light irradiation
for 5 hours; and 3) Ag-TiO2 PC upon white-light irradiation for 5 hours.