The light activation phenomenon in inverted P3HT:PCBM bulk heterojunction organic solar cells based on titanium oxide sublayer (TiOx) is characterized by fast acquisition of current-voltage (J-V) curves under light bias as function of time. TiOx layers were thermally treated under inert atmosphere at different temperatures prior active layer deposition and for every device an activation time was extracted. It is shown that the higher the TiOx annealing temperature, the faster the activation. The improvement of the overall device performances is also observed for devices with TiOx layers baked above 100 °C. The evolution of the characteristic of the organic semiconductors (OSC) device, from dielectric to diode, is attributed to the increase of TiOx conductivity by three orders of magnitude upon white light illumination. Additionally, devices based on baked TiOx present higher conductivity than those based on unbaked TiOx which would explain the gain in performances and the short activation time of the OSC. In order to understand the origin of the phenomenon, deactivation experiments were also performed under different conditions on OSC. The deactivation process was shown to be thermally dependent and fully reversible under inert atmosphere, which suggest that deep traps are responsible for the activation phenomenon. An optimal annealing temperature was found at 120 °C and gives a reasonable short activation time of approximately 1 min and photo conversion efficiency up to 4%.

1.
G.
Dennler
,
M. C.
Scharber
, and
C. J.
Brabec
,
Adv. Mater.
21
,
1323
(
2009
).
2.
Y.
Sahin
,
S.
Alem
,
R.
de Bettignies
, and
J.-M.
Nunzi
,
Thin Solid Films
476
,
340
(
2005
).
3.
G.
Li
,
C. W.
Chu
,
V.
Shrotriya
,
J.
Huang
, and
Y.
Yang
,
Appl. Phys. Lett.
88
,
253503
(
2006
).
4.
M. S.
White
,
D. C.
Olson
,
S. E.
Shaheen
,
N.
Kopidakis
, and
D. S.
Ginley
,
Appl. Phys. Lett.
89
,
143517
(
2006
).
5.
F.
Zhang
,
X.
Xu
,
W.
Tang
,
J.
Zhang
,
Z.
Zhuo
,
J.
Wang
,
J.
Wang
,
Z.
Xu
, and
Y.
Wang
,
Sol. Energy Mater. Sol. Cells
95
,
1785
(
2011
).
6.
J. B.
Kim
,
C. S.
Kim
,
Y. S.
Kim
, and
Y.-L.
Loo
,
Appl. Phys. Lett.
95
,
183301
(
2009
).
7.
F. J.
Zhang
,
D. W.
Zhao
,
Z. L.
Zhuo
,
H.
Wang
,
Z.
Xu
, and
Y. S.
Wang
,
Sol. Energy Mater. Sol. Cells
94
,
2416
(
2010
).
8.
C. Y.
Jiang
,
X. W.
Sun
,
D. W.
Zhao
,
A. K. K.
Kyaw
, and
Y. N.
Li
,
Sol. Energy Mater. Sol. Cells
94
,
1618
(
2010
).
9.
H.
Oh
,
J.
Krantz
,
I.
Litzov
,
T.
Stubhan
,
L.
Pinna
, and
C. J.
Brabec
,
Sol. Energy Mater. Sol. Cells
95
,
2194
(
2011
).
10.
R.
Steim
,
S. A.
Choulis
,
P.
Schilinsky
, and
C. J.
Brabec
,
Appl. Phys. Lett.
92
,
093303
(
2008
).
11.
P.
de Bruyn
,
D. J. D.
Moet
, and
P. W. M.
Blom
,
Org. Electron.
11
,
1419
(
2010
).
12.
F. C.
Krebs
,
Sol. Energy Mater. Sol. Cells
92
,
715
(
2008
).
13.
N.
Sekine
,
C.-H.
Chou
,
W. L.
Kwan
, and
Y.
Yang
,
Org. Electron.
10
,
1473
(
2009
).
14.
Z.
Xu
,
L.-M.
Chen
,
G.
Yang
,
C.-H.
Huang
,
J.
Hou
,
Y.
Wu
,
G.
Li
,
C.-S.
Hsu
, and
Y.
Yang
,
Adv. Funct. Mater.
19
,
1227
(
2009
).
15.
H.-H.
Liao
,
L.-M.
Chen
,
Z.
Xu
,
G.
Li
, and
Y.
Yang
,
Appl. Phys. Lett.
92
,
173303
(
2008
).
16.
A.
Kumar
,
S.
Sista
, and
Y.
Yang
,
J. Appl. Phys.
105
,
094512
(
2009
).
17.
A.
Wagenpfahl
,
D.
Rauh
,
M.
Binder
,
C.
Deibel
, and
V.
Dyakonov
,
Phys. Rev. B
82
,
115306
(
2010
).
18.
T.
Kuwabara
,
T.
Nakayama
,
K.
Uozumi
,
T.
Yamaguchi
, and
K.
Takahashi
,
Sol. Energy Mater. Sol. Cells
92
,
1476
(
2008
).
19.
T.
Kuwabara
,
C.
Iwata
,
T.
Yamaguchi
, and
K.
Takahashi
,
ACS Appl. Mater. Interfaces
2
,
2254
(
2010
).
20.
C. S.
Kim
,
S. S.
Lee
,
E. D.
Gomez
,
J. B.
Kim
, and
Y.-L.
Loo
,
Appl. Phys. Lett.
94
,
113302
(
2009
).
21.
H.
Schmidt
,
K.
Zilberberg
,
S.
Schmale
,
H.
Flugge
,
T.
Riedl
, and
W.
Kowalsky
,
Appl. Phys. Lett.
96
,
243305
(
2010
).
22.
Y.
Jin
,
J.
Wang
,
B.
Sun
,
J. C.
Blakesley
, and
N. C.
Greenham
,
Nano Lett.
8
,
1649
(
2008
).
23.
F.
Verbakel
,
S. C. J.
Meskers
, and
R. A. J.
Janssen
,
Appl. Phys. Lett.
89
,
102103
(
2006
).
24.
G.
Lakhwani
,
R. F. H.
Roijmans
,
A. J.
Kronemeijer
,
J.
Gilot
,
R. A. J.
Janssen
, and
S. C. J.
Meskers
,
J. Phys. Chem. C
114
,
14804
(
2010
).
25.
A.
Manor
,
E. A.
Katz
,
T.
Tromholt
, and
F. C.
Krebs
,
Sol. Energy Mater. Sol. Cells
98
,
491
(
2012
).
26.
M. R.
Lilliedal
,
A. J.
Medford
,
M. V.
Madsen
,
K.
Norrman
, and
F. C.
Krebs
,
Sol. Energy Mater. Sol. Cells
94
,
2018
(
2010
).
27.
N.
Golego
,
S. A.
Studenikin
, and
M.
Cocivera
,
Phys. Rev. B
61
,
8262
(
2000
).
28.
M. T.
Dang
,
L.
Hirsch
, and
G.
Wantz
,
Adv. Mater.
23
,
3597
(
2011
).
29.
M.
Burgos
and
M.
Langlet
,
J. Sol-Gel Sci. Technol.
16
,
267
(
1999
).
30.
G.
Li
,
Y.
Yao
,
H.
Yang
,
V.
Shrotriya
,
G.
Yang
, and
Y.
Yang
,
Adv. Funct. Mater.
17
,
1636
(
2007
).
31.
I. L.
Eisgruber
,
J. E.
Granata
,
J. R.
Sites
,
J.
Hou
, and
J.
Kessler
,
Sol. Energy Mater. Sol. Cells
53
,
367
(
1998
).
32.
S. H.
Szczepankiewicz
,
A. J.
Colussi
, and
M. R.
Hoffmann
,
J. Phys. Chem. B
104
,
9842
(
2000
).
33.
M. R.
Hoffmann
,
S. T.
Martin
,
W.
Choi
, and
D. W.
Bahnemann
,
Chem. Rev.
95
,
69
(
1995
).
34.
M.
Takahashi
,
K.
Tsukigi
,
T.
Uchino
, and
T.
Yoko
,
Thin Solid Films
388
,
231
(
2001
).
35.
K.
Pomoni
,
A.
Vomvas
, and
C.
Trapalis
,
Thin Solid Films
479
,
160
(
2005
).
36.
C. H.
Qiu
and
J. I.
Pankove
,
Appl. Phys. Lett.
70
,
1983
(
1997
).
37.
M. T.
Hirsch
,
J. A.
Wolk
,
W.
Walukiewicz
, and
E. E.
Haller
,
Appl. Phys. Lett.
71
,
1098
(
1997
).
38.
C.
Itoh
and
A.
Wada
,
Phys. Status Solidi C
2
,
629
(
2005
).
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