Metal-to-Particle Charge Transfer and its Role in Dye ...Metal-to-Particle Charge Transfer and its Role in Dye-Sensitized Solar Cells Sadig Aghazada GMF tutorial meeting. RSC Adv.,

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

Sadig Aghazada/ GMF group meeting3

Creutz-Taube Complex


J. Am. Chem. Soc., 1969, 91, 3988-3989

Robin-Day classification

Chem. Soc. Rev., 2006,35, 424-440


Very rapid

15102 s

J. Chem. Soc., Chem. Commun., 1987, 868-870


Sadig Aghazada/ GMF group meeting

Photocurrent action spectrum

J. Chem. Soc., Chem. Commun., 1987, 868-870

7

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


What if some cyanides are substituted with 2,2’-bipyridines?

waterCNbpyFe /2

4

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.


Transient absorption spectra

Inorg. Chem. 2002, 41, 1254-1262

*Ground state recovery (2nd order equal-concentration kinetic model) -191023 skobs



Incident Photon-to-Current Conversion Efficiency


11


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

12


What is the energy of an acceptor state?

EC

ET

TiO2

Acceptorstates

13

Observation

EC

ET

TiO2

Oxidation potential depends on solvent

MPCT

Wavelength

Ab

sorb

ance

Acceptorstates



Observation

EC

ET

TiO2

200-500 mV anodic shiftof oxidation potential



What about the spatial location of the acceptor state?

EC

ET

e

e

TiO2

EC

ET

TiO2

EC

ET

TiO2


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


What about the spatial location of the acceptor state?

17


Stark/Electroabsorption Spectroscopy

https://en.wikipedia.org/wiki/Johannes_Stark

Johannes StarkPhysics Nobel Prize laureate…

but unfortunately a strong supporter of Nazi regime.

18



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

19



J. Phys. Chem. B 2007, 111, 6695-6702

20


DFT and TD-DFT calculations

J. Am. Chem. Soc. 2004, 126, 15024-1502521


DFT and TD-DFT calculations

J. Am. Chem. Soc. 2004, 126, 15024-1502522


How to make an efficient solar cell based on MPCT?

Highest Occupied Molecular OrbitalAcceptor States

Extinction CoefficientRecombination


Sadig Aghazada/ GMF group meeting25https://en.wikipedia.org/wiki/Back_to_the_Future

26

Thank You for Your Attention!


Documents

Metal-to-Particle Charge Transfer and its Role in Dye ...Metal-to-Particle Charge Transfer and its Role in Dye-Sensitized Solar Cells Sadig Aghazada GMF tutorial meeting. RSC Adv.,