Upload
4th-international-conference-on-advances-in-energy-research-icaer-2013
View
172
Download
3
Embed Size (px)
Citation preview
Controlled morphology of electrodeposited CuSCN by
variation of applied bias voltage
ICAER-2013
Presented by SOHAM GHOSH
Dept. Energy Science and Engineering
Outline
• Sensitized solar cell (SSC),
• Motivation of the work,
• Applied bias dependent CuSCN morphology,
• Deposition time dependent CuSCN morphology,
• Application,
• Summary.
2
Dye Sensitized Solar Cell
3
Contains three individual layers
namely: the electron collector, absorber
layer or the dye and the electrolyte or
hole conducting material
e-h pairs separated due the presence
of band-offset at each interface
Easy fabrication; Less energy
consuming
Less pay-back period than Si based solar cell
Efficiency reached > 11% for lab based
devicesDSSC
Semiconductor Sensitized Solar Cell
4
•Dye is replaced by a low band-gap semiconductormaterial leading to an intermediate solid stateDSSC,•Electrolyte is also replaced by a solidsemiconductor making the whole device as a solidstate device.
CuSCN
FTO
ZnO
CdS
Au
ElectronHole
Degradation of dye with time (mainly the UV degradation)
Liquid electrolyte (improper packaging)
Motivation of the work
5
ZnO NanorodsSensitizerCuSCN
Contd.
6
FTO
CuSCN Nanorod
Electron Collector
Ag
Sensitizer
Contd.
• The percolation of hole collecting material into the pores in nanoporous
substrates is quite limited,
• Inverse structural design using p-type semiconductor nanorods as
building blocks,
• Surface area will increase and interface charge recombination will
reduce resulting better charge transport,
• Hole conducting pathway that is likely to be diffusion limited in
comparison to the hoping and grain boundary dominated transport
mechanism.
7
8
SEM images of the CuSCN films deposited at (A) -0.30 V, (B) -0.31 V, (C) -0.32 V, (D) -0.35 V, (E) -0.40 V (F) -0.42 V
Applied Bias Dependent CuSCN Morphology
XRD Pattern of CuSCN
9
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
* *
***
***
(10
7)
(24
1)
(01
5)
(00
6)
(10
1)
Inte
nsi
ty (
a.u
.)
2 Theta (deg.)
-0.30V
-0.31V
-0.32V
-0.35V
-0.40V
-0.42V
(00
3)
(10
4)
*
* FTO Glass
(11
3)
Deposition Time Dependent CuSCN Morphology
10
SEM of time dependant deposition film for (A) 1hr (B) 2hr (C) 3hr
TEM of CuSCN Nanorods
11
Transmission electron microscopy of CuSCN nanorods
Photovoltaic Application
12
Jsc = 8.8 mA/cm2Voc = 0.68FF = 0.63η = 3.9%
Summary
13
• Well shaped nanorods can be deposited under a potential of -0.3V,
• With increasing the applied potential nanorods were started
agglomerated gradually,
• With increasing deposition time the nanorods diameter started to
increase,
• Application for Semiconductor Sensitized Solar Cell.
14
Fabrication Methodology of Copper Thiocyanate
Experimental details:
• Electrolyte contains Cu+2 and SCN- ions in a water-ethanol system
Applied Potential: -0.3 to -0.42 V
Reaction at Cathode:
• Cu(ClO4)2 Cu2+ + 2ClO4-
• NaSCN Na+ + SCN-
• Cu+2 + SCN- CuSCN+
• CuSCN+ + e- CuSCN
15
16
SEM images of the CuSCN films deposited at (A) -0.30 V, (B) -0.31 V
17
SEM images of the CuSCN films deposited at (C) -0.32 V, (D) -0.35 V
18
SEM images of the CuSCN films deposited at (A) -0.40 V, (B) -0.41 V