Metal-to-Particle Charge Transfer and its Role in Dye ...Metal-to-Particle Charge Transfer and its...
Transcript of Metal-to-Particle Charge Transfer and its Role in Dye ...Metal-to-Particle Charge Transfer and its...
Metal-to-Particle Charge Transfer and its Role in Dye-Sensitized Solar Cells
Sadig Aghazada
GMF tutorial meeting
RSC Adv., 2014, 4, 29729-29734
Prussian Blue OxHCNFeFe IIIIV
2463
Intervalence Charge Transfer (IVCT) band
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Creutz-Taube Complex
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J. Am. Chem. Soc., 1969, 91, 3988-3989
Robin-Day classification
Chem. Soc. Rev., 2006,35, 424-440
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Very rapid
15102 s
J. Chem. Soc., Chem. Commun., 1987, 868-870
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Photocurrent action spectrum
J. Chem. Soc., Chem. Commun., 1987, 868-870
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Inorg. Chem. 2002, 41, 1254-1262
Note: No measurable change in the absorption spectrum when the concentration of LiClO4 was varied from 0 to 1.0 M.
leacetonitriTiOCNFe // 2
4
6
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What if some cyanides are substituted with 2,2’-bipyridines?
waterCNbpyFe /2
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leacetonitriTiOCNbpyFe // 2
2
4
leacetonitriTiOCNdpbFedashed
leacetonitriTiOCNdmbFedotted
leacetonitriTiOCNbpyFesolid
//
//
//
2
2
4
2
2
4
2
2
4
The spectra blueshift by 100 cm-1 and increase in intensity by about 10 % when 0.5 M LiClO4 added
Inorg. Chem. 2000, 39, 3738-3739Inorg. Chem. 2002, 41, 1254-1262
*Fitted with two Gaussians*Both MLCT
*Additional band (MPCT) is required for fitting
Note: oxidation potentials are strongly sensitive to solvent, while MPCT bands position are not.
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Transient absorption spectra
Inorg. Chem. 2002, 41, 1254-1262
*Ground state recovery (2nd order equal-concentration kinetic model) -191023 skobs
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Incident Photon-to-Current Conversion Efficiency
Inorg. Chem. 2000, 39, 3738-3739Inorg. Chem. 2002, 41, 1254-1262
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Sadig Aghazada/ GMF group meeting
J. Am. Chem. Soc. 2003, 125, 4637-4642Chem. Soc. Rev. 2009, 38, 115-164J. Phys. Chem. B 2007, 111, 6695-6702
EC
ET
TiO2
Acceptorstates
What is the energy of an acceptor state?
TkGh Bb 40
max
ox
redBCNMCb
K
KTkeEEG
n
ln'0
)(
04
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What is the energy of an acceptor state?
EC
ET
TiO2
Acceptorstates
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Observation
EC
ET
TiO2
Oxidation potential depends on solvent
MPCT
Wavelength
Ab
sorb
ance
Acceptorstates
Inorg. Chem. 2000, 39, 3738-3739Inorg. Chem. 2002, 41, 1254-1262
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Observation
EC
ET
TiO2
200-500 mV anodic shiftof oxidation potential
Inorg. Chem. 2000, 39, 3738-3739Inorg. Chem. 2002, 41, 1254-1262
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What about the spatial location of the acceptor state?
EC
ET
e
e
TiO2
EC
ET
TiO2
EC
ET
TiO2
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2/1max
91061.4
oscf
2
12max
52
122
max
2
1008.13
8
he
cmf e
osc
2
max4
2
max42)(
100.4102.9DADA
oscDA
r
d
r
fH
J. Photochem. Photobiol., A: Cgem. 1994, 82, 47Inorg. Chem. 2002, 41, 1254-1262
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What about the spatial location of the acceptor state?
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Stark/Electroabsorption Spectroscopy
https://en.wikipedia.org/wiki/Johannes_Stark
Johannes StarkPhysics Nobel Prize laureate…
but unfortunately a strong supporter of Nazi regime.
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Stark/Electroabsorption Spectroscopy
extFfF
int
12
3
S
S
D
Df
2
int2
2
22
/
30
/
15F
d
Ad
ch
C
d
Ad
hc
BAAA
Inter. Rev. Phys. Chem. 1998, 17, 307-329J. Phys. Chem. 1991, 95, 9773-9781
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Stark/Electroabsorption Spectroscopy
J. Phys. Chem. B 2007, 111, 6695-6702
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DFT and TD-DFT calculations
J. Am. Chem. Soc. 2004, 126, 15024-1502521
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DFT and TD-DFT calculations
J. Am. Chem. Soc. 2004, 126, 15024-1502522
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How to make an efficient solar cell based on MPCT?
Highest Occupied Molecular OrbitalAcceptor States
Extinction CoefficientRecombination
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Sadig Aghazada/ GMF group meeting25https://en.wikipedia.org/wiki/Back_to_the_Future
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Thank You for Your Attention!
Sadig Aghazada/ GMF group meeting