Photophysics and Dynamics of Dye Doped Conjugated Polymer ...
Supporting information
Photophysics and Dynamics of Dye Doped Conjugated Polymer Nanoparticles by Time resolved and Fluorescence Correlation Spectroscopy
Santanu Bhattacharyyaa, Suthari Prashanthib, Prakriti Ranjan Bangalb* and Amitava Patraa*
a) Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata, 700 032, India. b) Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500607, India
Calibration for FCS measurements: To measure and calculate any reliable dynamic parameters from FCS study one has to calibrate the instrumental parameters such as, focal area and the detection volume using a dye with known diffusion coefficient. We used Rhodamine-B (RhB) as standard and performed FCS measurements in aqueous solution under same conditions in which all other samples were to be done in this study. After completion of all measurement, we checked the autocorrelation data of RhB again and compared the same with the data taken prior to the titration experiment and both data were found to be the exactly same. For the diffusion coefficient, D (RhB), two different values were found in the literature: ~2.8x 10-10 m2 s-1 and ~4.27 x10-10 m2 s-1 measured by various methods at ~25°C.1 But the second value of diffusion coefficient was more widely accepted in FCS community than the first one, not only for RhB but also for other similar type of dyes such as Rhodamine 6G and Fluorescein. Hence, we accepted the second value of diffusion coefficient of RhB to calibrate the instrument. Figure S2 shows an example of FCS data obtained for RhB and diffusion time was obtained to be ~66 µs. Using following this equation
(τ D =
r02 , ) 4D
we obtained radial dimension of the confocal volume r0=335 nm and 1
concentration dependent FCS studies of RhB helps us to find the lateral dimension of confocal volume Zz was to be ~1738 nm. Hence, the obtained the confocal volume was to be (Vconf=(π/2)3/2 r02 Zz) ~0.453 fL and the effective volume (Veff =23/2xVconf) was to be ~1.3 fL. However, all measurements, both for reference and samples, were done using water from same source at the same temperature. Thus, the effect of temperature and viscosity were nullified during the calibration. All diffusion coefficients and dynamic parameters were determined at temperature 25° ± 2º C. We overcame the photobleching problem of fluorophore if any by reducing the laser intensity by using ND filters before exposing to the sample. Subsequently, the reduction of excitation intensity also helped to reduce the triplet state population significantly. Sample preparation for FCS measurements: The stock solution of RhB was prepared by dissolving in Milli-Q water at concentrations of 1x10-4 M and fresh 3~nM diluted solution of was prepared from the stock solution as required. Similarly aliquot of as prepared naoparticles colloid was diluted by mixing Milli-Q water till the autocorrelation signal reach to acceptable value.
a)
b) 2.5
0.3
3.0
2.0
0.9
1.5 1.0 0.5
1.0
0.0 300
400
500
600
700
800
900
Adsorbance
Adsorbance
Absorbance
1.5
Adsorbance
2.5
2.0
1.2
Pure NR NR doped in 100 nm PVK NP NR doped in 60 nm PVK NP NR doped in 40 nm PVK NP
0.6
0.5 wt % NR doped PVK 1.5 wt % NR doped PVK 1.8 wt % NR doped PVK
0.2
0.1
0.0 400
500
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Wavelength (nm)
Wavelength (nm)
0.3
0.5
0.0 300
400
500
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Wavelength (nm)
700
800
0.0 300
400
500
600
700
Wavelength (nm)
Figure S1: UV-vis absorption spectra of (a) NR doped PVK polymer nanoparticles 40, 60 and 100 nm; and (b) 0.5,1.5 and 1.8 wt % NR doped PVK polymer nanoparticles. 2
A)
Absorbance
1.5
100 nm PVK 60 nm PVK 40 nm PVK PVK in THF
1.0
0.5
0.0 300
400
500
600
Wavelength (nm)
B)
C)
400
500
Intensity (a.u)
Intensity (normalised)
100 nm PVK 60 nm PVK 40 nm PVK PVK in THF
600
100 nm PVK NP 60 nm PVK NP 40nm PVK NP
300
320
Wavelength (nm)
340 360 Wavelength (nm)
380
Figure S2: A) UV-Vis absorption spectra of pure PVK in THF and nanoparticles form having different size. B) Photoluminescence spectra (λex=340 nm) and C) PL-excitation spectra of PVK in THF solution and in nanoparticle form having different size range.
3
B 0 min 15 min 30 min 1 hr 2 hr 4 hr 6 hr 8 hr 10 hr 12 hr 24 hr 48 hr
(0 to 48 hr)
550
600
650
0 min 15 min 30 min 1 hr 2 hr 4 hr 6 hr 8 hr 10 hr 12 hr 24 hr 48 hr
(0 to 48 hr)
Intensity (a.u)
Intensity (a.u)
A
550
700
600
650
700
Wavelength (nm)
Wavelength (nm)
C 0 min 15 min 30 min 1 hr 2 hr 4 hr 6 hr 8 hr 10 hr 12 hr 24 hr 48 hr
Intensity (a.u)
(0 to 48hr)
550
600
650
700
Wavelength (nm)
Figure S3: Time dependent PL spectra of NR encapsulated 100 nm (A), 60 nm (B) and 40 nm (C) PVK polymer nanoparticles.
4
1.2 rhodamine fitting1
1.0
G(τ)
0.8 0.6 0.4 0.2 0.0 1
10
100
1000
10000 100000 1000000
Time (S)
Figure S4: Autocorrelation curves of Rhodamine B in water.
5
Photophysics and Dynamics of Dye Doped Conjugated Polymer Nanoparticles by Time resolved and Fluorescence Correlation Spectroscopy
Santanu Bhattacharyyaa, Suthari Prashanthib, Prakriti Ranjan Bangalb* and Amitava Patraa*
a) Department of Materials Science, Indian Association for the Cultivation of Science, Kolkata, 700 032, India. b) Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500607, India
Calibration for FCS measurements: To measure and calculate any reliable dynamic parameters from FCS study one has to calibrate the instrumental parameters such as, focal area and the detection volume using a dye with known diffusion coefficient. We used Rhodamine-B (RhB) as standard and performed FCS measurements in aqueous solution under same conditions in which all other samples were to be done in this study. After completion of all measurement, we checked the autocorrelation data of RhB again and compared the same with the data taken prior to the titration experiment and both data were found to be the exactly same. For the diffusion coefficient, D (RhB), two different values were found in the literature: ~2.8x 10-10 m2 s-1 and ~4.27 x10-10 m2 s-1 measured by various methods at ~25°C.1 But the second value of diffusion coefficient was more widely accepted in FCS community than the first one, not only for RhB but also for other similar type of dyes such as Rhodamine 6G and Fluorescein. Hence, we accepted the second value of diffusion coefficient of RhB to calibrate the instrument. Figure S2 shows an example of FCS data obtained for RhB and diffusion time was obtained to be ~66 µs. Using following this equation
(τ D =
r02 , ) 4D
we obtained radial dimension of the confocal volume r0=335 nm and 1
concentration dependent FCS studies of RhB helps us to find the lateral dimension of confocal volume Zz was to be ~1738 nm. Hence, the obtained the confocal volume was to be (Vconf=(π/2)3/2 r02 Zz) ~0.453 fL and the effective volume (Veff =23/2xVconf) was to be ~1.3 fL. However, all measurements, both for reference and samples, were done using water from same source at the same temperature. Thus, the effect of temperature and viscosity were nullified during the calibration. All diffusion coefficients and dynamic parameters were determined at temperature 25° ± 2º C. We overcame the photobleching problem of fluorophore if any by reducing the laser intensity by using ND filters before exposing to the sample. Subsequently, the reduction of excitation intensity also helped to reduce the triplet state population significantly. Sample preparation for FCS measurements: The stock solution of RhB was prepared by dissolving in Milli-Q water at concentrations of 1x10-4 M and fresh 3~nM diluted solution of was prepared from the stock solution as required. Similarly aliquot of as prepared naoparticles colloid was diluted by mixing Milli-Q water till the autocorrelation signal reach to acceptable value.
a)
b) 2.5
0.3
3.0
2.0
0.9
1.5 1.0 0.5
1.0
0.0 300
400
500
600
700
800
900
Adsorbance
Adsorbance
Absorbance
1.5
Adsorbance
2.5
2.0
1.2
Pure NR NR doped in 100 nm PVK NP NR doped in 60 nm PVK NP NR doped in 40 nm PVK NP
0.6
0.5 wt % NR doped PVK 1.5 wt % NR doped PVK 1.8 wt % NR doped PVK
0.2
0.1
0.0 400
500
600
700
Wavelength (nm)
Wavelength (nm)
0.3
0.5
0.0 300
400
500
600
Wavelength (nm)
700
800
0.0 300
400
500
600
700
Wavelength (nm)
Figure S1: UV-vis absorption spectra of (a) NR doped PVK polymer nanoparticles 40, 60 and 100 nm; and (b) 0.5,1.5 and 1.8 wt % NR doped PVK polymer nanoparticles. 2
A)
Absorbance
1.5
100 nm PVK 60 nm PVK 40 nm PVK PVK in THF
1.0
0.5
0.0 300
400
500
600
Wavelength (nm)
B)
C)
400
500
Intensity (a.u)
Intensity (normalised)
100 nm PVK 60 nm PVK 40 nm PVK PVK in THF
600
100 nm PVK NP 60 nm PVK NP 40nm PVK NP
300
320
Wavelength (nm)
340 360 Wavelength (nm)
380
Figure S2: A) UV-Vis absorption spectra of pure PVK in THF and nanoparticles form having different size. B) Photoluminescence spectra (λex=340 nm) and C) PL-excitation spectra of PVK in THF solution and in nanoparticle form having different size range.
3
B 0 min 15 min 30 min 1 hr 2 hr 4 hr 6 hr 8 hr 10 hr 12 hr 24 hr 48 hr
(0 to 48 hr)
550
600
650
0 min 15 min 30 min 1 hr 2 hr 4 hr 6 hr 8 hr 10 hr 12 hr 24 hr 48 hr
(0 to 48 hr)
Intensity (a.u)
Intensity (a.u)
A
550
700
600
650
700
Wavelength (nm)
Wavelength (nm)
C 0 min 15 min 30 min 1 hr 2 hr 4 hr 6 hr 8 hr 10 hr 12 hr 24 hr 48 hr
Intensity (a.u)
(0 to 48hr)
550
600
650
700
Wavelength (nm)
Figure S3: Time dependent PL spectra of NR encapsulated 100 nm (A), 60 nm (B) and 40 nm (C) PVK polymer nanoparticles.
4
1.2 rhodamine fitting1
1.0
G(τ)
0.8 0.6 0.4 0.2 0.0 1
10
100
1000
10000 100000 1000000
Time (S)
Figure S4: Autocorrelation curves of Rhodamine B in water.
5
