硒化镉CdSe量子点的制备和应用
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Synthesis and Applications of CdSe Quantum Dots
Speaker: 林天全 Other Members： 刘海涛 冷 雪 李 菲 李 魁
1
What are Quantum Dots ?
A quantum dot is a nano-particulate semiconductor, whose excitons are confined in all three spatial dimensions.
Injecting
Solvent: TOPO (300℃)
Cooling
Prevent further nucleation
Nucleation
4 MIT M.G. Bawendi, et al. J. Am. Chem. Soc. 1993, 115 (19): 8706-8715.
Room temperature optical absorption spectra of CdSe nanocrystallites dispersed in hexane and ranging in size from ~1.2 nm to 11.5 nm.
18
Prashant V. Kamat, J. Am. Chem. Soc. 2007, 129: 4136–4137.
Linking CdSe QDs to TiO2 Surface with a Bifunctional Surface Modifier
Prashant V. Kamat. J. Phys. Chem. CSOC. , 2008, 112 (48): Prashant V. Kamat. J. AM. CHEM. 2006, 128: 18737-18753. 2385-2393.
8
CdAc2 + Na2SeSO3
Green Methods
CdAc2· H2O
By stiring
CdSe
Se S
O
O
NaOH
Dissolving
O
C2H5OH+H2O
By stiring
Autoclave (40-150℃)
OA
Na2SeSO3
Nucleation
9
Y.D. Li. Inorganic Chemistry. 2008, 47(11): 5022-5028.
17
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Quantum dot sensitized solar cell—QDSSC
Left: The dependence of electron transfer rate constant on the energy difference between the conduction bands. Right: Scheme illustrating the principle of electron transfer from two different size CdSe quantum dots into TiO2 nanoparticle.
Prashant V. Kamat, et al. J. AM. CHEM. SOC, 2008, 130(12): 4007-4015.
23
Happy New Year!
戊子年冬
19
a
b
Bifunctional organic molecule
I-V characteristics of (a) OTE/TiO2 and (b) OTE/TiO2/MPA/CdSe films. Electrolyte 0.1 M Na2S. Fast capture of electrons at the quantum dot interface remains a major challenge for efficient harvesting of light energy.
6
CdO + Se/ODE + ODE = CdSe
CdO
Dissolving
OA+ODE
Heating
Injecting
Se+ODE
Mixture (300℃)
Cooling
Nucleation
X.G. Peng, et al. Angewandte Chemie-International Edition, 2002, 41(13): 7 2368-2371.
Prashant V. Kamat. J. AM. CHEM. SOC. 2006, 128: 2385-2393.
20
源自文库
Emerging Strategies to Capture and Transport Photogenerated Electrons
Photocurrent generation using CdSe-nC60 composite clusters IPCE：Incident Photon to Current-generation Efficiency
Fluorescence of the CdSe with different emission (λex ) 365nm
Y.D. Li, et al. Inorganic Chemistry. 2008, 47(11): 5022-5028.
10
Core–shell structures
TEM
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Artistic impression of a rainbow solar cell assembled with
different size CdSe quantum dots on TiO2 nanotube array.
15
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Quantum dot sensitized solar cell—QDSSC
Nitrogen doped
Principle of operation of quantum dot sensitized solar cell
5
CdO + TOPSe + TOPO + TDPA
CdO
Dissolving
CdSe
TDPA+TOPO (300-320℃)
Cooling
Injecting
Se + TOP
Solution (270℃)
Cooling
Nucleation
X.G. Peng, et al. J. Am. Chem. Soc, 2001. 123(1): 183-184.
14
Schematic diagram showing the strategies to develop quantum dot (semiconductor nanocrystal) based solar cells: (a) metal-semiconductor junction (b) polymer-semiconductor (c) semiconductor-semiconductor systems
1240 Eg (eV ) (nm)
D (2.6786 109 )λ 4 (4.9348 106 )λ 3 (3.4222 103 )λ 2 1.0511 λ 121.74
M.G. Bawendi, et al. J. Am. Chem. Soc. 1993, 115 (19): 8706-8715.
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Left: Photocurrent response as a function of the amount of TiO2 deposited on carbon fiber electrode (CFE)； Right: Scheme showing the electron transport through SWCNT and SEM image of the SWCNT-TiO2 composite.
Charge injection from excited CdSe quantum dots into TiO2 nanoparticles is followed by collection of charges at the electrode surface. The redox electrolyte (e.g. sulfide/polysulfide) scavenges the holes and thus ensures regeneration of the CdSe.
Drug Screening
Biological probe
12
―The emergence of semiconductor nanocrystals as the building blocks of nanotechnology has opened up new ways to utilize them in next generation solar cells.‖
Versatile two-phase approach to synthesize highly luminescent CdE (E=S, Se, Te) QDs.
L.J. An, et al. Journal of Physical Chemistry C. 2007, 111: 5661-5666.
Martin Green
13
Four major ways to utilize semiconductor dots in solar cell
① Photoelectrodes comprising quantum dots arrays
Prashant V. Kamat A. J. Nozik
Photoluminescence
Q. J. Sun, et al. Nature Photonics. 2007,1, 717.
11
LED
Solar cell
Laser devices
Applications of Quantum Dots
Medical Imaging Biological Labeling Biochip
Quantum Dot Solar Cell
② Semiconductor nanostructure polymer solar cell
③ Quantum dot sensitized solar cell
④ Metal-semiconductor photovoltaic cell
A. J. Nozik. Physica E, 2002 (14): 115-200.
2
Structure of CdSe Quantum Dots
Wurtzite
Zinc blende
Rock salt
戴全钦. 吉林大学博士学位论文，2007
3
Cd(CH3)2 + TOPSe + TOPO
Solution A: Cd(CH3)2 + TOP
Combining
CdSe/TOPO
Solution B: Se + TOP
Lopez-Luke, T. J. Phys. Chem. C. 2008, 112:1282–1292.
16
Quantum dot sensitized solar cell—QDSSC
Charge injection of excited CdSe quantum dot into TiO2 nanoparticle. The scheme on the right shows the modulation of energy levels (and hence the charge injection) by size control.
Speaker: 林天全 Other Members： 刘海涛 冷 雪 李 菲 李 魁
1
What are Quantum Dots ?
A quantum dot is a nano-particulate semiconductor, whose excitons are confined in all three spatial dimensions.
Injecting
Solvent: TOPO (300℃)
Cooling
Prevent further nucleation
Nucleation
4 MIT M.G. Bawendi, et al. J. Am. Chem. Soc. 1993, 115 (19): 8706-8715.
Room temperature optical absorption spectra of CdSe nanocrystallites dispersed in hexane and ranging in size from ~1.2 nm to 11.5 nm.
18
Prashant V. Kamat, J. Am. Chem. Soc. 2007, 129: 4136–4137.
Linking CdSe QDs to TiO2 Surface with a Bifunctional Surface Modifier
Prashant V. Kamat. J. Phys. Chem. CSOC. , 2008, 112 (48): Prashant V. Kamat. J. AM. CHEM. 2006, 128: 18737-18753. 2385-2393.
8
CdAc2 + Na2SeSO3
Green Methods
CdAc2· H2O
By stiring
CdSe
Se S
O
O
NaOH
Dissolving
O
C2H5OH+H2O
By stiring
Autoclave (40-150℃)
OA
Na2SeSO3
Nucleation
9
Y.D. Li. Inorganic Chemistry. 2008, 47(11): 5022-5028.
17
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Quantum dot sensitized solar cell—QDSSC
Left: The dependence of electron transfer rate constant on the energy difference between the conduction bands. Right: Scheme illustrating the principle of electron transfer from two different size CdSe quantum dots into TiO2 nanoparticle.
Prashant V. Kamat, et al. J. AM. CHEM. SOC, 2008, 130(12): 4007-4015.
23
Happy New Year!
戊子年冬
19
a
b
Bifunctional organic molecule
I-V characteristics of (a) OTE/TiO2 and (b) OTE/TiO2/MPA/CdSe films. Electrolyte 0.1 M Na2S. Fast capture of electrons at the quantum dot interface remains a major challenge for efficient harvesting of light energy.
6
CdO + Se/ODE + ODE = CdSe
CdO
Dissolving
OA+ODE
Heating
Injecting
Se+ODE
Mixture (300℃)
Cooling
Nucleation
X.G. Peng, et al. Angewandte Chemie-International Edition, 2002, 41(13): 7 2368-2371.
Prashant V. Kamat. J. AM. CHEM. SOC. 2006, 128: 2385-2393.
20
源自文库
Emerging Strategies to Capture and Transport Photogenerated Electrons
Photocurrent generation using CdSe-nC60 composite clusters IPCE：Incident Photon to Current-generation Efficiency
Fluorescence of the CdSe with different emission (λex ) 365nm
Y.D. Li, et al. Inorganic Chemistry. 2008, 47(11): 5022-5028.
10
Core–shell structures
TEM
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Artistic impression of a rainbow solar cell assembled with
different size CdSe quantum dots on TiO2 nanotube array.
15
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Quantum dot sensitized solar cell—QDSSC
Nitrogen doped
Principle of operation of quantum dot sensitized solar cell
5
CdO + TOPSe + TOPO + TDPA
CdO
Dissolving
CdSe
TDPA+TOPO (300-320℃)
Cooling
Injecting
Se + TOP
Solution (270℃)
Cooling
Nucleation
X.G. Peng, et al. J. Am. Chem. Soc, 2001. 123(1): 183-184.
14
Schematic diagram showing the strategies to develop quantum dot (semiconductor nanocrystal) based solar cells: (a) metal-semiconductor junction (b) polymer-semiconductor (c) semiconductor-semiconductor systems
1240 Eg (eV ) (nm)
D (2.6786 109 )λ 4 (4.9348 106 )λ 3 (3.4222 103 )λ 2 1.0511 λ 121.74
M.G. Bawendi, et al. J. Am. Chem. Soc. 1993, 115 (19): 8706-8715.
Prashant V. Kamat. J. Phys. Chem. C, 2008, 112 (48): 18737-18753.
Left: Photocurrent response as a function of the amount of TiO2 deposited on carbon fiber electrode (CFE)； Right: Scheme showing the electron transport through SWCNT and SEM image of the SWCNT-TiO2 composite.
Charge injection from excited CdSe quantum dots into TiO2 nanoparticles is followed by collection of charges at the electrode surface. The redox electrolyte (e.g. sulfide/polysulfide) scavenges the holes and thus ensures regeneration of the CdSe.
Drug Screening
Biological probe
12
―The emergence of semiconductor nanocrystals as the building blocks of nanotechnology has opened up new ways to utilize them in next generation solar cells.‖
Versatile two-phase approach to synthesize highly luminescent CdE (E=S, Se, Te) QDs.
L.J. An, et al. Journal of Physical Chemistry C. 2007, 111: 5661-5666.
Martin Green
13
Four major ways to utilize semiconductor dots in solar cell
① Photoelectrodes comprising quantum dots arrays
Prashant V. Kamat A. J. Nozik
Photoluminescence
Q. J. Sun, et al. Nature Photonics. 2007,1, 717.
11
LED
Solar cell
Laser devices
Applications of Quantum Dots
Medical Imaging Biological Labeling Biochip
Quantum Dot Solar Cell
② Semiconductor nanostructure polymer solar cell
③ Quantum dot sensitized solar cell
④ Metal-semiconductor photovoltaic cell
A. J. Nozik. Physica E, 2002 (14): 115-200.
2
Structure of CdSe Quantum Dots
Wurtzite
Zinc blende
Rock salt
戴全钦. 吉林大学博士学位论文，2007
3
Cd(CH3)2 + TOPSe + TOPO
Solution A: Cd(CH3)2 + TOP
Combining
CdSe/TOPO
Solution B: Se + TOP
Lopez-Luke, T. J. Phys. Chem. C. 2008, 112:1282–1292.
16
Quantum dot sensitized solar cell—QDSSC
Charge injection of excited CdSe quantum dot into TiO2 nanoparticle. The scheme on the right shows the modulation of energy levels (and hence the charge injection) by size control.