Vacuum UltraViolet (VUV) Spectroscopy of TPB films
Temperature Effect on TPB Emission Lineshape
Roberto Francini
Department of Physics
Università di Roma Tor Vergata
Contacts:
[email protected]
+39 06 7259 4505
TPB Workshop 10/19/2012
SLIDE 1
Investigated TPB samples were grown at the
Gran Sasso National Laboratory LNGS, INFN L’Aquila, Italy
Evaporated TPB Films
Layer density (µg/cm2)
Fraction of TPB in polystyrene
(Weight fraction %)
167
350
1
725
Glass substrate
10
900
20
1175
40
1450
1875
50
74
177
Samples obtained by dip-coating
of glass substrates in polystyrene
containing TPB
317
VIKUITI substrate
476
769
1376
1498
Samples obtained by evaporation
of TPB on different substrates
TPB Workshop 10/19/2012
SLIDE 2
Jablonsky diagram
TPB Workshop 10/19/2012
SLIDE 3
Configurational coordinates
diagram
PhotoLuminescence
(PL) Spectra
Absorption Spectra
Photo Excitation (PE) Spectra
TPB Workshop 10/19/2012
SLIDE 4
Vacuum Monochromator
McPherson model 234/302
Focal length 0.2 m equipped
with a 30 Watts Deuterium
lamp model 632
with MgF2 window,
Spectral range 115 – 380 nm.
Closed-cycle Helium Cryostat
Temperature range
12 – 300 K
TPB Workshop 10/19/2012
SLIDE 5
Measured VUV Intensity distribution of Deuterium lamp
Emission Intensity (arb. units)
Deuterium Lamp Spectrum
15
10
128 nm
5
0
110
120
130
140
150
160
Wavelength (nm)
TPB Workshop 10/19/2012
170
180
SLIDE 6
TPB in polystyrene on glass
Emission Spectra
Excited at 128 nm
3
1%
10%
20%
40%
8
40%
Optical Density
Emission Intensity (arb. units)
10
Absorption Spectra
6
4
2
20%
1
10%
2
0
350
1%
0
400
450
500
550
600
Wavelength (nm)
TPB Workshop 10/19/2012
300
350
400
450
500
Wavelength (nm)
SLIDE 7
12
444
1.0
6
4
0.5
2
0.0
300
400
500
Wavelength (nm)
600
TPB in PMMA
J. Huang et al., J. Lumin. 81 (4), 285 (1999)
440
436
432
428
8 0
10 20 30 40
TPB fraction in Polystyrene matrix (mass %)
Integrated Emission Intensity (arb. units)
Optical Density
TPB in
polystyrene
8
Emission Intensity (arb.units)
10
Peak Wavelength (nm)
1.5
7
6
5
4
3
2
0
10
20
30
40
TPB fraction in Polystyrene matrix (mass %)
TPB Workshop 10/19/2012
SLIDE 8
TPB evaporated on glass
Spettri diExcited
Emissione
Emission Spectra
at 128 nm
Eccitati a 128 nm
Emission Intensity (arb. units)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
250
TPB evaporato su vetro
500
750
1000
1250
1500
1750
2000
1750
2000
2
TPB density (g/cm )
428
16
2
Peak Wavelength (nm)
Emission Intensity (arb. units)
20
350 g/cm
2
725 g/cm
2
1175g/cm
2
1875g/cm
12
8
4
0
350
427
426
425
424
423
422
400
450
500
Wavelength (nm)
550
600
TPB Workshop 10/19/2012
250
500
750
1000
1250
1500
2
TPB density (g/cm )
SLIDE 9
TPB evaporated on VIKUITI
1.25
Emission Spectra Excited at 128 nm
1.20
2
Sample A7 - 177 g/cm TPB-Vikuiti
1.15
1.05
1.00
0.95
0
250
500
750
1000
1250
1500
2
TPB density (g/cm )
2
Sample A7 - 177 g/cm TPB-Vikuiti
1.0
0.8
0.6
0.4
Emission Intensity (arb. units)
1.10
Integrated Emission Intensity (arb. units)
Peak Emission Intensity (arb. units)
1.30
2.0
1.5
12 K
1.0
87 K
150 K
200 K
0.5
250 K
300 K
0.2
350
0.0
0
50
100
150
200
Temperature (K)
250
400
450
500
550
600
650
Wavelength (nm)
300
TPB Workshop 10/19/2012
SLIDE 10
2
TPB evaporated on VIKUITI (177 g/cm )
Intensity (arb. units)
1
T = 12 K
(0,0)
(0,4)
Frank-Condon Integrals
(0,5)
0.18 eV
S=2
0.1
mm
0.01
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Huang-Rhys Factor
3.2
Energy (eV)
- Vibrational mode energy = 0.18 eV = 1450 cm -1
- Stretching mode vibration of trans-butadiene
TPB Workshop 10/19/2012
3.4
ΔQ is the coordinate displacement
between the ground state
and the excited state
SLIDE 11
TPB in polystyrene on glass
Emission Spectra of TPB
on VIKUITI and in polystyrene
Excited at 128 nm
Temperatura 87 K (LAr)
4
exc = 128 nm
3
T = 12 K
50 K
2
87 K
150 K
1
200 K
300 K
0
350
400
450
500
550
Wavelength (nm)
600
650
Normalized PL (arb. units)
Emission Intensity (arb. units)
Emission Spectra Excited at 128 nm
TPB on VIKUITI
TPB in polystyrene on glass
16
12
T = 87 K
8
4
0
350
400
450
500
550
600
Wavelength (nm)
TPB Workshop 10/19/2012
SLIDE 12
Photoluminescence (PL) and Photoexcitation (PE)
in the UV-VIS range
TPB in polystyrene on glass –TPB
T =in polistirene
300 K su vetrino
(emi= 422 nm)
PL (arb. units)
(emi= 460 nm)
1.0
0.5
(exc= 348 nm)
(exc= 380 nm)
(exc= 400 nm)
3
2
1
300
320
340
360
380
400
420
440
0
300
460
350
Wavelength (nm)
400
450
500
550
600
Wavelength (nm)
2 – su
TPB evaporated on VM2000 – 600
μg/cm
TVM2000
= 300
Campione
TPB evaporato
(600 K
g/cm )
2
(em= 422 nm)
(emi= 445 nm)
3
(emi= 460 nm)
2
1
0
8
PL (arb. units)
0.0
PE (arb. units)
PE (arb. units)
(exc= 295 nm)
4
(emi= 445 nm)
1.5
(exc = 265 nm)
(exc = 280 nm)
(exc = 295 nm)
6
(exc = 348 nm)
(exc = 380 nm)
(exc = 400 nm)
4
2
300
320
340
360
380
400
420
440
460
Wavelength (nm)
TPB Workshop 10/19/2012
0
300
350
400
450
500
550
600
Wavelength (nm)
SLIDE 13
Normalized Emission Intensity (arb. units)
2.0
1.6
1.2
Sodium Salicylate
TPB/polystyrene on glass
TPB on VIKUITI
Blank VIKUITI
T = 300 K
0.8
0.4
0.0
300 350 400 450 500 550 600 650
Wavelength (nm)
Emission Spectra (excited at 128 nm) of TPB evaporated on VIKUITI, TPB
in polystyrene on glass and of a VIKUITI blank, compared with the
emission spectrum of a Sodium Salicylate film on glass.
TPB Workshop 10/19/2012
SLIDE 14