main - hynsr.korea.ac.krhynsr.korea.ac.kr/members/theses/M_khkim.pdfAbstract For studying the...
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Transcript of main - hynsr.korea.ac.krhynsr.korea.ac.kr/members/theses/M_khkim.pdfAbstract For studying the...
Abstract
For studying the physical characteristics of poly(p-phenylenevinylene)
(PPV) and copolymer, we measured the UV absorbance, PL emission, J-
V characteristics, TOF, and AC impedance. From the UV & PL exper-
iments, band structure and exciton transfer, localization of PPV, copoly-
mer were analyzed. The HTD (hole transport device) current behavior of
poly[2-methoxy-5-(2-ethyylhexyloxy)-1,4 -phenylenevinylene] (MEH-PPV) is
characteristic for space charge limited with a field-dependent mobility (Poole-
Frenkel effect). On the other hand, The HTD and ETD (electron trans-
port device) current of poly[2-(9’,9”-dihexylfluorenyl)-1,4- phenylenevinylene)]
(DHF-PPV) followed the Fowler-Nordheim tunnelling model at high electric
field. Enhanced electron tunnelling, hole confining is found in device with
bilayer electrode (LiF/Al), which showed that the presence of LiF at the
polymer/metal interface caused band bending of polymer, thus lowering the
electron-injection barrier height. TOF experiments showed a trap-controlled
transport behavior and field, temperature dependency of hole mobility in
MEH-PPV. These results are in good agreement with ones obtained by J-
V analysis. Impedance characteristics of ITO/DHF-PPV/Al device showed
the Schottky barrier is formed at the metal/polymer contact, which is accom-
panied by significant band bending and a high internal electrical field, thus
dominated with injection limited characteristics.
Abstract
Poly(p-phenylenevinylene) (PPV)
, DC J-V, TOF (time of flight), AC
. UV
one-electron !" #$%
PL (photoluminescence) &' (! "#$)* +,
- %& ./0 1"23 '+,-( 4 . DC J-V
poly[2-methoxy-5-(2-ethyylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)
HTD (hole transport device) )56 SCLC (space charge limited con-
duction) Poole-Frenkel +,- 7 8' "כ! 4 . 9 # poly[2-
(9’,9”-dihexylfluorenyl)-1,4-phenylenevinylene)] (DHF-PPV) HTD ETD
(electron transport device) )56 %& *+%& ) :$%&
"כ! 4 . LiF, # )*; )56 <= #
+,- ); > +,-#23 :$%& ? "כ! 4 . MEH-PPV(
# TOF ' )- % ' ( 4
#$% DC J-V # ' ( 4 . DHF-
PPV( # AC @AB 4 7 C ( ,
#- DA ) 8 VE 0 )- (F- . GH # AC
DHF-PPV( #)*; )56> injected limited current
(ILC)C I - DA ) 7 .& */+!, )- DC J-V -
-%J. 4 .
Contents
1 1
2 4
2.1 "')*; #$' . . . . . . . . . . . . . . . . . . . . 4
2.1.1 #$' . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.2 PPV K . . . . . . . . . . . . . . . . . . . 6
2.1.3 01234-%/& 01 5656 . . . . . . . . . . . . . . . . 7
2.2 Injection limited current . . . . . . . . . . . . . . . . . . . . . 9
2.2.1 2% % # ) @A-1 . . . . . . . . . . . . . . . . . 9
2.2.2 Hopping # ) @A-1 . . . . . . . . . . . . . . . . 10
2.2.3 :$%& # ) @A-1 . . . . . . . . . . . . . . . . . 11
2.2.4 Band bending . . . . . . . . . . . . . . . . . . . . . . . 11
2.3 Transport limited current . . . . . . . . . . . . . . . . . . . . 13
2.3.1 SCLC & . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.2 ) ' ) . . . . . . . . . . . . . . 20
2.4 Two carrier current . . . . . . . . . . . . . . . . . . . . . . . . 23
i
2.4.1 Plasma . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.4.2 Langevin bimolecular recombination . . . . . . . . . . 24
2.5 Time of flight . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.6 AC . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.7 (! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.7.1 "#$)* 7 .& (! 756 . . . . . . . . . . . 33
2.7.2 UV absorbance, PL emission spectra . . . . . . . . . . 34
3 37
3.1 ( LM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.2 )*; <=#$ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.3 , . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.4 DC J-V , . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.5 Time of flight , . . . . . . . . . . . . . . . . . . . . . . . . 43
3.6 AC , . . . . . . . . . . . . . . . . . . . . . . . . 44
4 46
4.1 !%- . . . . . . . . . . . . . . . . . . . . . . 46
4.1.1 UV absorbance . . . . . . . . . . . . . . . . . . . . . . 46
4.1.2 PL emission spectra . . . . . . . . . . . . . . . . . . . 54
4.2 DC J-V !%- . . . . . . . . . . . . . . . . . . . . . . . . 57
4.2.1 MEH-PPV . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.2.2 DHF-PPV . . . . . . . . . . . . . . . . . . 65
4.2.3 LiF, # ,)*; . . . . . . . . . . . . . . . . 70
ii
4.3 Time of flight !%- . . . . . . . . . . . . . . . . . . . . . 73
4.4 AC !%- . . . . . . . . . . . . . . . . . . . . . 83
5 89
Bibliography 91
iii
List of Figures
2.1 PPV K NO'' . . . . . . . . . . . . . . . . . . . 6
2.2 SCLC & 7 .& J-V . . . . . . . . . . . . . . . . . . . 19
2.3 TOF ((- )56 . PQR"S' . . . . . . . . . . 28
2.4 AC !" # ·345 > )23 . . . . . 32
2.5 "#$)* 7 .& (! 5656 . . . . . . . . . . . . . . . 34
2.6 4, "'·O"' 8-* . . . . . . . . . . . . . . . . . . . . . 35
3.1 DHF-PPV MEH-PPV K. . . . . . . . . . . . . . . 38
3.2 DHF-PPV, MEH-PPV bandK . . . . . . . . 39
3.3 "')*; K . . . . . . . . . . . . . . . . . . . . . . . 40
3.4 TOF . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.1 MEH-PPV, DHF-PPV UV 4 &' . . . 50
4.2 PPV one-electron K . . . . . . . . . . . . . . . . . . 51
4.3 UV 4 &' 6")TU VW)TU OXY . . . . 52
4.4 UV 4 &' Z)TU [=)TU OXY . . . . 53
4.5 (LM PL &' . . . . . . . . . . . . . . . . . . . . 56
iv
4.6 HTD(MEH-PPV) % !%- . . . . . . . . . . . . . . 58
4.7 HTD(MEH-PPV) % !%- . . . . . . . . . . . . . . 61
4.8 HTD(MEH-PPV) % 7 .& γ T−1 PQR"S' . . . . . . . 62
4.9 HTD(MEH-PPV) % 7 .& γ T−2, T−3/2 PQR"S' . . . 63
4.10 HTD(MEH-PPV) % 7 .& µ0 PQR"S' . . . . . . . . . . 64
4.11 DHF-PPV DC !%- . . . . . . . . . . . . . . . . . . . 67
4.12 FN :$%& # DHF-PPV DC PQR"S' . . . . . . . . . 68
4.13 DC !%- . . . . . . . . . . . . . . . . . . . . 69
4.14 LiF, # DC !%- . . . . . . . . . . . . . . . . . 72
4.15 MEH-PPV 4\]4 . . . . . . . . . . . . . . . . . . . . . . 75
4.16 70 V TOF !%- . . . . . . . . . . . . . . . . . . . . 76
4.17 ' F1/2 . . . . . . . . . . . . . . . . . . . . 77
4.18 TOF23 # ' % . . . . . . . . . . . . 80
4.19 γ % . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.20 µ0 % . . . . . . . . . . . . . . . . . . . . . . . . . 82
4.21 7 V LED(DHF-PPV) > )23 . . . . . . 86
4.22 LED(DHF-PPV) AC !%- . . . . . . . . . . . . . . . . 87
4.23 fc 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
v
List of Tables
2.1 &'789 5656 7 .& VΩ . . . . . . . . . . . . . . . . . . . . . . 18
2.2 &'789 5656 7 .& VTFL . . . . . . . . . . . . . . . . . . . . 18
2.3 +#$ *(_כ a . . . . . . . . . . . . . . . . . . 31
4.1 MEH-PPV % 7 .& DC ' . . . . . . . . . . . 60
4.2 MEH-PPV % 7 .& TOF ' . . . . . . . . . . 79
vi
Chapter 1
-bc Xd7; -% ); )*e"23fg (%& )( hi8'0 ,\j
DA ( . 0- 1977:9 polyacetylene ) k3Xd
lm - 4 ,%& ) Xd7; \n"', ?Xd .-
SSH O:;!" ,%& "' ) [1, 2]. GH # Xd7;
23fg -%<- o pC %/& qr Xd7; "'
st? .PQu23 )"' #"')*; (OLED) )\]+,-&'
0:, N, 1".; )0 4 [3, 4, 5].
"')*; v [=wr x= yz 23fg / 2 1 ?Xd 7o| .
"')*; 7; ( # )*; Xd7; ( # )*; 23 > 4
~ ?@ 7; ( # )*; ( OELD (OLED), Xd7; ( # )*
; ( PELD (PLED)C Xd # . 7; Xd7; +#$+#$ - 0 >
0Xd . 7; 1< - Xd7; > 7; k3 .2$ - " *+ UA
-%%/ 2% 3 7; O *+#$% \] + BC . )*
1
; <=#$ Xd7; !"=#&, S'$"=#& (0 # > 1 I
7; !% & 5456 !"o| <=.2$ . Xd7; 9 # %&
' ), ?7)- ( \j 4 > 0 D( *+ > H41
0 . GH # Xd7; )*e" 1990:9 '"#$ j'0 PQE
Poly(p-phenylenevinylene) (PPV)( # )"' "'st # lm,%&
> <- o pC H [3]. PPV
@7 > F : )( 568#$ &(*
lm 2% !" /56#23 Xd7; ( - > 1 I # GH
# > 1#23 XdD 568#$ e"AGB HG% . GH # A<=( !"!%
PPV \n"'? . C D\j \n"' PPV (
- F'4?7 ?7E 0 .; # ?79 E 4 . 5 H(HXd I4
( :;%& ); @A\j J( I ( !% N)H0 ?7 E 4
Xd ); @A\j> 2 F * +G5 J> !% F'4?7 > 0
\j . 9 # (copolymer)( - ( ?79 HI 4
. J A%& 0 10:9( %/&23fg ?H% PPV (
DC J-V, Time of flight (TOF), AC O:; # GH
( 4,-J .
JA PPV( #%/& .; #
- )*; +,K / KK/ \j [= DA7
#23 H . 6" )TU23 UV (absorbance), PL
&' 23 !%-( . !"
. Z )TU23 ) 23fg DC J-V( "'
)*; )56 B .#$- !" "'(LM ) ' )
2
·%, &'789, )*; wr Xd AC (
@AB 4, DA DC ) 7 .& )· ) \]4 (electric modulus)
)- wr . [= )TU23 ); 23fg yz
( # TOF "' (LM ) ' )- %
, )56 !" .
3
Chapter 2
2.1
"')*; K GH 5656> . )0$- "',#23 5AH&
(0 # KDA: ); @A-1, 423 , > 0Xd #
KE 0 +#$+#$ GH <(F !" .; # K> e" # .
0- J "', B .#$ @A3 ZXd )*;
.& /wr # "<= )0$- "',- e" 0,)*;
wr!" #23 .
2.1.1
"')*; ) @A-1DA: "' 8'E 0 '#$- 0
\]>%23 H (0 L %M - L- :; .
4
1. )0$#23DA: - ); @A-1 -
2. @A-1 - ); > %/&wrM6 )0$#23 ' 423 -
3. "', - ); > !% (! 5A !% -
4. (! .GN '%/& # 8-*( bc O"' 8-* "' -
5. <#=o ) > %/&wrM6 )0$#23 NGH > )56 -
O6")TU@A-1-%& )0$-"',I 3P\j> ..;0$
8' ./0 "', HOMO (highest occupied molecular orbital)I
)3P e" \j ?- @A-1%& )3P ,%& '< 5?
\j . PQ )3P I !% @A-1 0 ,\j ?~ U
)56( injection limited current (ILC)C Xd # . %/&wr23 )3P ((
-O #$ !% (< 0.4 eV) @A-1%& "', 7 C !% .
"כ! Z )TU 423 - - /-%01 # Q- . 423 -%& "'
, %& ) ' -% +,-, &'789 e" ,%& '<
5? . GH # %& "', Xd Xd )*; ( -
U k3( U "', DA !% '< 5?o ?0R
. GH # "', 7 C <= #? )56( transport limited current
(TLC)C Xd # . - ); > :; @A-1? !% - ); > 23
!% (! & Xd8-* # . - !%,"'- . GH
# - (!%& !"= 7 C singlet, triplet#23 > 4 . Singlet
(! 8-* - & (fluorescence) qrXd triplet 8-* -
(phosphorescence) 12S .& "')*; '?.GN Xd%&4
5
Figure 2.1: PPV (a) K, (b) NO''.
M(lifetime) T UA "' bc 0 P'Q # . GH # (!%&
"', O"' 8-* bc ( ); #23 7 (dissociation) .
08#$#23(! & 0P'Q bc &U@VH (7 ) %&%/&
wrM6 )0$#23 NGH> \j ?Xd )*; )5623 , .
2.1.2 PPV
π-conjugated polymer poly(p-phenylenevinylene) (PPV) K A/&
)* 4\n > ); ( > 0Xd sp2pz ? @NO'' & # . sp2 ? @NO''
5AXd [=\n ); σ !% 5AH backbone & Xd pz N
O'' 5AXd ); K; #A/&)* pz ); !1J\j?
H O"#$)* π ( R . PPV C D\j π 23!"
, ) BC\j . :;%& π-conjugated polymer 3W
) DA %/&23fg -% > 0~ &%"כ! Peierls transition
7 .& K UA [6]. Peierls transition !%T > -%( Uk3
K !%T (0-%!%) DE%& !%T ( !%)> %/&!" U K#
6
23 3 UA -%H AGB#23 GH # K XYZ e"
\j . GH # XYZ π ); /-% %/&Oyu ~ GH #
DA -% <- o pC %/&23fg -% :\j "כ!.
2.1.3 -
); 01234 %/&23 @A-1?bc %/& 01234#23
NwrH01234-%/&01%&" _כ . GH #01%&
"')*; !% )56> ) @A-1 qr0 o p- ) 423
qr0 !% _כ# S ?$% )*; +,K # '<
4"= . 01234-%/& 01 ) 01 5656( %/&
!%Xd #1" bc .2$ #3W1"( > # . )01%&01
234- %/& -%.4 v .& KK/ 7 C GH > 023 > 4 #
-%.4 v 7 .& [= > 0 5656 wr 5F[ [7].
(1) 01 (ohmic contact)
01%& !% P& %/& -%.4 ( )) k3 *+%&
-%.4( > 001234 01 !% Xd ); !% N&%/&
-%.4 (> ); ) k3 %& -%.4( > 0 01234 01 !%
. &%"כ! %/& qrDA - OXY!" 01234- %/& I 01
wr#23 #$ #23"כ! 01- 01 ; ) F'> %/&
F'k3 "כ! # . -%%/ J-V \] 01
234 %/& 2%#23 ?0R? ) k3 ,%& -W ) ( @A-1
0 , %& ) O& \]( > 0$% )0$ ) @A-1 9
( ) '< 0" *+%& ) OO& \]( > &
7
. 01234 )0$ ); @A-1 \j !" %/& st- 3W
+,- .;; :$%& bc 7 *+%& -%.4 (
!%) %& -%.4 ( ); !%)( > 0 01234 01 # .
(2) 01 (neutral contact)
%/& 01234 01 )#23 1"23 Z 01 -% I
-%.4> :;bc % -%.4> GC ); &'789 S 7 C "'?0R
# . )#23 UA( ) > 2 FXd$ (band bending)
2 F .
(3) !"01 (schottky contact)
); !% 01234 -%.4> %/& -%.4 k3 # !% Xd
!%01234-%.4> %/&-%.4k3 #$%&!% . \K
K/ ); ()%/&01234#23 ' %/&.; (L)
6-1, ?0R\j . \ 01 !% 01234M6 )> *+o 0: DA )
@A- ); \j %/& 01234M6#23 ' \j ?Xd %/&wr23 01234
M6 )> o 0: DA ) @A- Schottky3P )v ( 0$(
4 UE 0 ); > %/&M6#23 ]HH: 4 2 F\j .
8
2.2 Injection limited current
) @A-1%& )0$ (LM23 ) > @A-1 !" U 3P e" 7
C Z > 023 7( 4 . 3P e" 0 ,bc (( 4 -O
#$ U(< 0.4 eV) ) @A-1 <= # 2 F#23 )56 (LM bulk
7 C GC & [54]. 0- GH # 3P \j ?- )56 @A-1%& <=
#5?\j?~ GH # )56( injection limited current (ILC)C XdDA.& .
GH # ) @A-1 .%& ) .2$( U I U Z> 023 >
4 . ) 7 *+ U :$%& # +,-> Xd )
U 2% %- hopping # +,-> [19, 54].
2.2.1
2% % # ) @A-1 !% 3P *+ > kTk3 # !%23 (
LM 0 ,Xd N 3P *+ - #23"כ! L- :;%&
Richardson-Schottky (RS) : [15].
J = AT 2 exp (−qφB/kT ) (2.1)
A 4Xd, φB 7HL% 3P#23 image charge23 # 3P TUL
+,-( %/&' # .
φB = Φ −√
qF
4πε(2.2)
A =4πqmk2
h3
Φ #-%U )0$-"',-%.4v 23 Schottky./0
3P C Xd # . -.2$ (LM ) '> #$%& !%(µF 3/4 ≤ 5) )
9
)56 I )56 !" !"0Xd )56/-%%& RS 0 P'Q
Xd o R"- :; JK fgo| # [16]. GH # )56( back flow )56C Xd
DA8'$% U %& L- :; .
J = NeµF exp (−eΦ/kT )
(2.3)
N = 2(2πmkT/h2)3/2
2.2.2 Hopping
%&01234%/&23 ) @A-1 hopping&
L %M ( #23"כ!#> 01234 )0$8'./023DA:01-
> E V %/& "#$)* S23 hopping !" H( Xd >
. GH # disorder hopping system # Monte Carlo simulation#
23 L- :;%& )56/-% EH HI 4 [17, 18, 19].
J = eν0
∫ ∞
a
dx0 exp (−2γx0)ωesc(x0) ×∫ ∞
−∞dE
′Bol(E
′)g[U0(x0) − E
′] (2.4)
%M6 6" 7 +#$ L- :; .
ν0 : hopping @A
γ : "#$)* %/&0:L 4
x0 : ) > L hopping( 4 bc
wesc : ) > st- e"!% ( E
a: )0$ bulk 6" hopping sitebc
Z)TU g(E) Gaussian DOS(density of states) function#23+#$+#$
%& L-:; . F0st- ), φ3P*+ , x01
10
- bc .
g(E) =Nt√2πσ
exp
(− E2
2σ2
)
Bol(E) =
exp (−E/kT ) , E > 0
1 , E < 0
U0(x) = φ − e2
16πεx− eF0x
2.2.3
) U LJ 2% % hopping # +,->
0- ) 7*+ U:$%& # ) @A-1 \j .:
$%&%& J#23 .;; WKB I ( \]I ( 4 .
PQ Fowler-Nordheim (FN)&%& ) > #=+#$7HL%3P :$%&
@A-1 Xd > # 23 )56/-% %& L- :; [20].
J =q3
8πhφF 2 exp
[8π(2m)1/2
3hqφ3/2F−1
](2.5)
φ ,L% 3P Xd m%& ) +, -%1< .
2.2.4 Band bending
"', Z> 1000 A )*; .;%& "', )
' 6-1(#23 > $ 2 F O#23 ?0R+#$ ( 4 . 0-
<=23 )*; ( - - ?0R GH #23_כ )0$M6
band bending -%H . st- !%.#23 # bipolaron & band
11
bending #23"כ! ?0R+#$ . GH # band bending%& Ca, Al,
LiF/Al )0$ # )*; XPS, UPS 7 ?
[22, 23, 24]. M WX # 3P # )56 @A-1( band bending%& _כ
# <*(_כ . :$%& & GH # band bending +,-( XdG%
L- :;%& ?0R+#$( 4 [21].
ln
(I
F 2
)= C1 +
C2
F + Fin
(2.6)
Fin built-in ) .
12
2.3 Transport limited current
2.3.1 SCLC
Space charge limited conduction (SCLC) &%& J#23 1"
56 1v - )56 # $% L- :; > "' # [7].
> ) @A-1 ) YUL 5A !" ./0 & I # .
) @A-1 ) - XdG% $%, @A-1 # 01 # . &%"כ!
)56 )0$<= # 2 F "כ! # .
) ; ) ' ) Xd &'789 e" '< 5?0 ,
.
C ) ; ) /-% Mazwell-Boltzmann \]( 7 8'Xd, %/&- 8"B )
/-% Fermi-Dirac \]( 7 .& .
) ) " c (LM qrDA I- 2%#23 ?0R ) V%/&
; # )56 &%*(_כ ( .
) Poole-Frenkel+,- Onsager&, % , ) ':;
%& *+%& ) +,- ( .
I ) (LMZ dC -, x = 0 - ) @A-101#23 Xd x = d -
) > > )0$#23 1v #23 NOWX # .
&'789F'7.4 L-:;%&> ); (valence band)ZW[
./0 S E ) @A-1 01 bc x .4 .
h(E, x) = Nt(E)S(x) (2.7)
Nt(E) &'789 ./0 7.4 Xd S(x) &'789 ( 7.4
.&'789 #> 0 ) (p)- Xd> (U(LMqrDA )
13
%& L- :;%& Poisson 7 .& .
dF (x)
dx=
q[p(x) + pt(x)]
ε=
ρ
ε(2.8)
)56/-% L- :; .
J = qµpp(x)F (x) (2.9)
p(x) pt(x) +#$+#$ @A-1 ; ) &'789 8"B ) /-%(
qr$% L- :; .
pt(x) =
∫ Eu
El
h(E, x)fp(E)dE
p(x) = Nv exp(−EFp/kT )
fp(E) Fermi-Dirac7.4 .&'789 !%2 F
!%( H SCLC )56/-% Lk35F[ .
1) &'789 2 F !% (trap free SCLC)
!% pt(x) = 023 *C 4 #23 2.9 .;)- 2F (x)( \&X # L
2.8( wr-1 - L- :; .
2F (x) · dF (x)
dx=
d[F (x)]2
dx=
2J
εµp
L- :;%& !%\]KK/
V =
∫ d
0
F (x)dx (2.10)
7 - L- :;%& Mott-Gurney E 4 .
J =9
8εµ
V 2
d3(2.11)
14
!% )56 PQP 2.2 trap free SCLC :;%& .; \j .
Mott-Gurney L- :;%& ) ' ) A
> $% PF-SCLC ( 4 .
µ(F ) = µ0 exp(γ√
F )
2.8, 2.9 !%\]KK/(F (x = 0) = 0) \]I - L- :;%&
PF-SCLC % .
J =2µ0ε
d
((F 3/2
γ− 3F
γ2+
6F 1/2
γ3− 6
γ4
)exp(µ
√F ) +
6
γ4
)(2.12)
"כ! I - L- :; [14].
J ≈ Aµ0εV 2
d3exp(Bγ
√F ) (2.13)
A B4 . #23DA: J )( (0 \j
4 .
2) &'789 e" !% (trap SCLC)
&'789 ]'%& GH\n 8 234 ./0 S e" !% QE%&
&'789- T_%& &'789#23 > 4 . PQP 2.2 T_%& &'789 !%
K > 1 ohmic ' 0 23 &'789 " TFL'
\j . QE%& &'789 !% ohmic ' 0 VΩ \j ?Xd
K > 2 ' ~ ' )56/-% L- :; .
J =9
8εµθa
V 2
d3eff
(2.14)
15
deff &'789 8"B ) ; ) O_(-% # ( 723
# "כ!. θa ) ) /-% wr # ; ) /-% OK 23 L- :;%&
> & .
θa =gpNv
Ha
exp(−Et/kT )
L#23 010 ./0 XYZ &'789 04.423 7 !% )56
PQP 2.2 T_%& trap SCLC :; ( K > 2 DA7 bcJ
0 ,Xd 23 TFL' \j ?~ ' )56/-% L-
:; .
J = KV m+1
d2m+1
(2.15)
K = q1−mµNv
(m + 1
2m + 1
)m+1 (m
m + 1
ε
Hb
)m
Hb ,&'789 /-% . 08#$#23 010 ./0 XYZ &'789
> .4237 !%QE%&&'789-T_%&&'789#23 >4 .
O QE%& &'789 !% > ,%& &'7897( > 0 ./0 (Etm)k3
8' ./0 (Ef )> *+%& !%23 )56/-%%& LJ 2.14 :;
Xd θa L- :; .
θa =gpNv
Hd
exp
−Etm
kT+
1
2
( σt
kT
)2
σt> 7stSav .T_%&&'789!% Etm 8'
./0k3 U23 TFL' )56%& 2.15 :;Xd Hb L
- :; .
Hb = (H/2)g−1p exp (Etm/mkT )
16
+#$ 1" )56 PQP 2.2 :; L qrDA ) > [=(U
ohmic > DA ) > qrDA ) k3 ,o 0- SCLC'#23 ]HH>
\j . U !%\] ) VΩC Xd # . VΩ 0 lm &'789 e" ( !%
)56 &'789 "\j ?~ U ) VTFL C Xd Xd )
VTFL ]H\j?-&'789 v \j?H&'789 2 F SCLC7 8'\j .
DC % E%& J-V K ( &'789 04.4723 e"
bc T_%& > 723 e"( U 2.15 !"( 4 .
% K (m+1)> +#$% 8'23PQR"S'm-log(J/Vm+1)(
PQ+G5 4 . PQR"S' H, µN כ: PQR"S' m-log(J/Vm+1) K
(s) 0%a(ic)( L- :; ( 4 [50, 51, 52].
H ≈ 2ε
d2q· 10s
µN ≈ d
q· 10ic
17
Table 2.1: &'789 5656 7 .& VΩ.
&'789 5656 VΩ
2 F !% 98
qp0d2
ε
QE%& 8 234(> .4) 7 98
qp0d2
θaε
04.4(T_%& > .4) 7 qd2Hb
ε
(p0
Nc
)1/ll+1
l
(l+12l+1
)(m+1)/m
Table 2.2: &'789 5656 7 .& VTFL.
&'789 5656 VTFL
QE%& 8 234 7 qHad2
2ε
T_%& 8 234 7q(Ha−p0)d2
2ε
04.4(T_%& > .4) 7 qd2
ε
98
Hb
Nv
(l+1
l
)l ( l+12l+1
)l+11/(l−1)
QE%& > .4 7qNt(unfilled)d
2
2ε
18
Figure 2.2: SCLC . 7 .& J-V (n = K ).
19
2.3.2
AGBe"E 0 disordered organic materials, molecularly doped polymers, low
molecular weight organic glasses, polyconjugated polymers,%&-%
# ) ' L- :;%& ) ' )
'( 4 .
µ = µ0 exp(γ√
F ) (2.16)
GH # ) ' W ?@ Poole-Frenkel effect (behavior) C Xd
~ &%"כ! 2.9 2.16( 4"= - o R" :;%& Poole-Frenkel emission
I UA .
J ∼ F exp
[−q(φB − √
qF/πε)
kT
](2.17)
2.16%wr ##23 Gill, GDM, CDM[=
> 0( Lk35F[ . Gill%& TOF o R":;
%& <=( [10].
µ0 = µ∞ exp(−∆/kT )(2.18)
γ = B (1/kT − 1/kTo)
∆ ) * ./023 % 0 , . µ0 F →0 -% U
) ' Xd µ∞ F →0 Xd T→ ∞-%U ) ' . γ )
' ) Xd B, To 4 . :; Gill !" <=
( 2.18%& כ: ?# +#$ כ:
J ,.#S . GH # wr 001E 0 (- ./0 -%
L %M G% ¡4P 5AH0Xd . PQ Bassler > (3
20
7( Xd ; S hopping#23 -%H ) ' Monte
Carlo simulation !" .PQ!%- L-:;%& Gaussian Disorder
Model (GDM) <=( [11].
µ0 = µ∞ exp[− (2σ/3kT )2]
(2.19)γ = C
[(σ/kT )2 − Σ2
] σ b ./0 -% +,-23 # > (3 DOS c Xd C
4, Σ ( -%( qr 423fg 1.5k3 #$%& U%-כ: 2.25(
d . GDM%& PQ'3 *+%& )(> 105 V/cm) -
#\]> 0? "כ! .!"!% @A)- hoppingS(
(L 1 XdG% L-:;%& Correlated Gaussian Disorder Model (CDM)
<=(? [12, 13].
µ0 = µ∞ exp[− (3σ/5kT )2]
(2.20)γ = C
[(σ/kT )3/2 − Γ
]√ea/σ
a S( bc Xd Γ ( -% +,-( qr 423fg
'S /-% # . Correlated media C = 0.78, Γ = 2 .
9 # σ wr L- :;%& <=( [13].
σ = 2.35ep/εa2 (2.21)
p T0$; 9eS&' . µ∞ 01 # I ); B ' .4
!1:P- Q-?H Xd > - L- :;%& <=(( 4 [79].
µ∞ =ea2vph
σexp (−2a/L) (2.22)
21
vph (∼ 1012s−1) hopping Q- @AB 4 Xd L%& "#$)*
T ( 12S .
22
2.4 Two carrier current
2.4.1 Plasma
LED HTD ETDG ); @A-1 #23<= #
0 , . LED )56 - ); # UA HTD ETD
)56 k3 \j . %/&- - ); !% !" )56 f+
-%H . \ !%%& Hag ) > ¢£ -%H 4 Xd
XYZ > 23 -%GH 23 -%H 4 . GH # Z ) @A-1 A<=
( (0 \j injected-plasma23h, 4 . !%MU@V!כ"H
ag "#$)* !% 7 C 7 # [8].
O Hag "#$)* i !% -%H U -% # 4M > 0\j
. U n ≈ p, τn ≈ τp I > > F . "כ! )56
- L- :; .
J =125
18ετµpµn
V 3
L5(2.23)
%& 7 *+%& ) !" 4 Xd #$%& ) # )
# SCLC> @A#23 h, 4 .
L#23"#$)* !%' 2 F !%23%3P #0% plasma>
@A-1? U bimolecular-recombination plasmaC Xd # . ) (LM
n ≈ p C Xd ( 4 Xd U )56/-% %& L- :; j 4 .
J =
(9π
8
)1/2
ε µpµn(µp + µn)/µR1/2 V 2
L3(2.24)
µR =ε〈vσR〉
2e
23
µR%& recombination cross section (RCS)#23234 v.4 Xd234
v ); ( wr234 . -.2$ RCS> " I !% ) )
56 .;0$ SCLC( 7 8'Xd L0$ ); SCLC( 7 8'\j
.9 #- ); > - '%&#$o Hag #- . !%
% ) # !% h, 4 Xd )56%& L- :; .
J =9
8ε(µn + µp)
V 2
L3(2.25)
2.4.2 Langevin bimolecular recombination
-%%/ LED e"!% (recombination)-%& Langevin -1 "כ!
#23 G% [47]. Langevin -1 e"!% -%& L- :;%& >
"' # . -.2$ +#$+#$ ) \]#23 \j ?0R - )
!%%& ; -- kinetically bimolecular 7 .& . _כ# KK/%&
) mean free path (λ)> ) capture %/&0:L (rc)k3 #$o o| #
"כ!. coulomic capture radius (rc) L- :; [9].
rc =e2
4πεkT
5, λ < rc-% U Langevin KK/ -56 "כ!. 2% ) # )56
); > 0 Xd wr#23 µT23 YUL >st( ?0R+#$( U
); !" ZWk _( )56/-% %& L- :; .
J = nheµT F = nheµTe
4πεr2c
(2.26)
µT = µp + µn, nh -N /-% .
%/&0:L rc st-#23 H> , )56 L- :; .
i = J × 4πr2c = nhµT e2/ε (2.27)
24
b ); !% # Xd?0R+#$ - recombination rate(γehnhe)
L- :; .
γehnhe = nhµT e2/ε(2.28)
γeh = eµT /ε
γeh ; ); wr # bimolecular rate 4 .
25
2.5 Time of flight
) '( ,( 4 > 123 DC J-V, time of flight (TOF),
AC , transient EL, field effect transistor (FET) > 1 .
> 01#23 ) '( bY 4 > 1 time of flight (TOF)
. TOF )*; LED :; #M6 )0$ ¤AM bc %/&¤AM
\j -b . GH # )*; ) -% \j !;%H@AXd ¤AM # )0$ M6 yz
( ¥*o S . PQGH- ¤AM # )0$ M6 (LM (! -H0Xd
DA!;%HS "כ! )!"7 (dissociation)?-- )
; > -H & . -.2$ .;0$M6 .GN OA - ?0R ); 23 .;
0$M6#23 > \j ?Xd %& %/&wr )0$ L0$ M6#23 hi8'\j ?H
'( (4 .%/&wr23 ); '( !"¤AM # )
0$ L0$#23 .GN OAH @A- . - )56( , - PQ
P 2.3- :;%& )56-(( (I-t) PQR"S'( ( 4 [25, 72]. ) > (LM
( - ~ !;%$"= ((%& PQP 12S "כ! τ> ?Xd ) '
(µ) L- :; \]I ( 4 .
µ =d
τF=
d2
τV(2.29)
d (LM Z Xd F, V (LM > !"S ), ) .
TOF E%& )56( !" # & Lk3; . PQ
dispersive transport(multiple trapping model) stochastic .%&Z'
)56( L- :;%& #23 !" [26].
I(t) ∝ t−(1−αi), t < τ
t−(1+αf ), t > τ(2.30)
26
αi, αf7I)-423fg 0- 1I כ: :Xd7I 5> -+#$
+#$ &%כ: #$o & . "#$)* S> ./0 wr!" 04.4#23 7
1" multiple trapping!"7I423 (dispersive transport)
( U αi = αf = kT/E023 *C 4 .
"#$)* S> L- :; ./0 wr!" > (3 7( !%
( > -
N(E) =2Nt
σ· E
σexp
[−
(E − Et
σ
)2]
αif L- :;%& כ: ( 4 .
αif =2kT
σ
(ln
L√2µcτF
)1/2 (1 ± 1
2ln
L√2µcτF
)(2.31)
(+) αi , (−) αf Xd µc τ &'789? ) ) '
4M (lifetime) .
27
Figure 2.3: TOF ((- )56 . PQR"S'.
28
2.6 AC ! "!"
(impedance) ) )23 DAlUL, -% HI 4
J ) *(_כ. &%"כ! (0 )*; @AH& )- )
#23 !" "'?0R # )56 O23 . J &%*(_כ
(R), +!, (L), )1< (C) 4 . <= ) )*;
%& +!,, )1< +#$+#$ '4+G1#23 "כ! o
pC [= > 0> #23 -%H . DC 4#23 ?
(R)%& Ohm > 1:Pc 7 C L- :; .
R =V
I
-.2$, - > & )*; AC ) > !"S - %& Ohm
> 1:Pc !" !"& . 0- )1< +!,> e" \j ?-
PQ%& )56 ) (phase) '< J\j . 7 C AC
(Z) L- :; )*.4> .
Z(ω) =V (ω)
I(ω)= R + jX
)*; AC !" !" > )23( -1( 4 ~ (
0 PQP 2.4 345 )23 45 )2323 > 4 . 45 )23
L - :; .
Z = Rs + jXs =
Rs + jωLs
Rs + j/(ωCs)
29
345 )234H, (admittance)( ~ L
- :; .
Z = Gp + jBp =
Gp + jωCp
Gp + j/(ωLp)
G AC */+!, (conductance) Xd B <=Z, (susceptance)
. +#$ &%כ: ¦ h 2.3 "כ! 23 a > F . GH _כ
)*> )23 @AB 4 7 C > )23 +#$ *(_כ כ: GC 0
W ~ Z, Y, C∗ )*- PQR"S'( k3- PQ )23 W
4 [27].
30
Table 2.3: +#$ *(_כ a.
a :L 0
Z Impedance Ω Z = Rs + j Xs = |Z|ejθ
Rs Resistance Ω Rs = Gp
G2p+B2
p
Xs Reactance Ω Xs = − Bp
G2p+B2
p
Y Admittance S Y = Gp + j Bp = 1Z
Gp Conductance S Gp = Rs
R2s+X2
s
Bp Susceptance S Bp = Xs
R2s+X2
s
Cs Series capacitance F Cs = − 1ωXs
= Cp(1 + D2)
Cp Parallel capacitance F Cp = Bω
= Cs
1+D2
Ls Series inductance H Ls = Xω
= LPQ2
1+Q2
Lp Parallel inductance H Lp = − 1ωBp
= Ls(1 + 1/Q2)
Q Quality factor Q = 1DF
= Xs
Rs= Gp
Bp= tan θ
DF Dissipation factor DF = tan(π/2 − θ) = tan δ
M Modulus M = 1κ∗ = jωZC0
31
θ
δ
ω
θ
δ
ω
θ
δ
ω
θ
δ
ω
Figure 2.4: AC !" # ·345 > )23 .
32
2.7 #$%#
2.7.1 & $ #$%#
m: >Pd#23 n ); U#$ (! (exciton) C Xd DA
.& . (!%& oO, ) oO#23 &!" 4 . GH #
(!%& - ); "#$)* 7 C Frenkel, Wannier-Mott (WM),
Charge-Transfer (CT) (!#23 > 4 [28]. Frenkel (!%&
7; ( ; ) ); !%23 PQ @A)- 7; (
; ) bck3 #$ .(< 5 A) (! '%& -1; § &'(
I =, C . -1%/&-1; '#23h, 4 . Frenkel(!%&7
; K noble-gas, ionic crystale" Xd!%./0 1 eV( >
& . Wannier-Mott (WM) (!%& GH 7; ( ; ) !;%© - )
; > !% Xd !%23 @A 7; ( a#$ !" (!
5AXd H - ); ( m: >Pd wr#23 #$ . !% (!%&
.2$ 40 ∼ 100 A # %/&0:L > 0Xd !%./0 0.1 eV >
. L#23 Frenkel- WM (! ( 1"23 charge-transfer (CT)
(! . CT (!%& UU23 01 # 7; ( positive polaron-
negative polaron U#$#23 h, 4 . 0- C D\j "#$)* !% 7
; crystal @A 7; - .2$ # (L 1 bc @A VW( !1:P
#$ U . AGBe" O"#$)* CT (! self-consistent field I
 L %M Xd . (! /-%> #$o (!-(! (L 1 (
( 4 U CT (!%& <#=o ) _( )- a #$
quasiparticle23 h, 4 . U # ); Hamiltonian%& L- j 4
33
Figure 2.5: (! 5656; (a) Frenkel, (b) WM, (c) CT.
.
H0 = T + Ve−h + Vpse
T V'./0, Ve−h ); m: !%./0, Vpse @A
!% pseudopotential . Ve−hk3 pseudopotential #$ U 5,
@A !X; ( a #$ I U CT (!%& O"#$)* ?H Xd PQ %/&wr
23 @A !X; ( a #$ #$ U Ve−hk3 pseudopotential c
CT (!%& "#$)* .
2.7.2 UV absorbance, PL emission spectra
(!%& !"= 7 C singlet, triplet (!(exciton)#23 p . sin-
glet(!!%(! 5AXd ); !"=< .&
34
Figure 2.6: 4, "'·O"' 8-*.
!% Xd triplet (! !% +#$+#$ !"= :;%& < > 0 !%
. PQP 2.6%& Z > 0 (! wr # ./0 S PQP . PQP k3Q
#$1" S0 S1, S2 #23 ? -%& 4 -#23 UV
(absorbance) !" ..GN!"?!% 100% singlet
(! -H& . )#23?!%k307; !% 1
: 3OK 23 singlet, triplet(! ?0R .PQGH PPV:;%&Xd7;
); B '.4 f+YZV (L 1#23 !" singlet (! & OK
50 ∼ 60 % E 0 .& [29, 30, 31]. .GN )#23 (!%&
spin-orbit coupling#23 # intersystem crossing (ISC) !" 23 XY
> F #~ k3 triplet (! ./0> siglet (! ./0>
UA singlet (! triplet(!#23 )- - @A . .GN
35
!" ? !% - !" triplet (! ?0RK . singlet
(! 8-* - N .GN & (fluorescence) C Xd triplet (!
8-* - N.GN (phosphorescence)C Xd # . singlet excited
state picosecond 4M :Xd ./0 S UV PL
, ( 4 . Triplet (!%& #$1" (S0) !"= v 23 !" .;
; #23 #$1"23 8-*> 010?H UA millisecond
K 4M- #$%& +,K > & . PQP 2.6 k3 Q +#$ ./0 S ,
%& &' S (vibration state)( > & . S e"> %- # UV 4
e@&' k3 . .GN )#23 (!%&
+#$ S #$S(S1,S2,...)23 % L S0 S23 8-* - .GN qr
\j . 9 # S0 S &' S> UA PL EL
&' GH\n N> \j .
36
Chapter 3
3.1 # &כ
J "',#23 (LM \j homopolymer copoly-
mer ()23 > 4 . homopolymer23 poly[2-methoxy-5-
(2-ethyylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) poly[2-(9’,9”-
dihexylfluorenyl)-1,4-phenylenevinylene)] (DHF-PPV)[42]> .
23 MEH-PPV DHF-PPV( 1:10- 1:1 OK 23 -b random
[42]( . +#$+#$ 7; 1<%& DHF-PPV 420 × 103 Xd
(10 : 1)%& 290 × 103, (1 : 1)%& 280 × 103 . "'-%
K highest occupied molecular orbital (HOMO), lowest unoccupied
molecular orbital (LUMO) S( PQP 3.1, 3.2 qr . DHF-PPV
XdG%wr - &-% XY4? # Xd "כ!
MEH-PPV American Dye Source, Inc -1 I .
37
Figure 3.1: DHF-PPV MEH-PPV K.
" @A23 1,1,2,2-tetrachloroethane( I #$% A> #23 chloroform,
xylene I 10 mg/ml 23 (LM( F'4 I .
3.2 '(
) DC J-V )*; \j [= > 023 7( 4 .
O )56 *+%& -%.4( > 0 Au, ITO
)0$ # hole transport device (HTD)( <=#$ . L#23 )
; )56 %& -%.4( > 0 Li:Al, Al )0$
# electron transport device (ETD)( <=#$ . HTD ETD #M6
)0$%& @A ) )G; ); @A-1 \j, .& M6 )0$
%& .& ) @A-1 /)* -%.4> .& )0$ Of@
-b )*; . "')*; light emitting device (LED) ) Z @A
38
!
"
Figure 3.2: DHF-PPV, MEH-PPV bandK.
-1 \j )0$ ITO, Li:Al23 Of@ # )*; . TOF
)*; LED K> :;Xd #M6 ¤AM # ITO )0$ %/&¤AM # Z
30nm Al )0$ I # . PQP 3.3 "כ! DC )*; (
- !" [/& 01234 5456 bc ITO> 5456
[/& :& ª", -b . GH # )0$[/& @7 (LM Laurell
Ws-200-4T2 spincoator( !"= #& . (LM Z( o @A
Zg;1\j(!% free standing .!"=#&!%568#$
Z rpm 7 C )- ~ wr1\6#23 o R" :;%& \]> .
d ∝ (rpm)−1/2
rpm%& spincoator ) )234 . "', Z Tencor <=
#$ Alpha-Step 500 , Xd (LM Z> o @A Zg;1bc
39
Figure 3.3: "')*; K.
40
_(-% 0 , U )*; TU ) 1<(capacitance) , \]I
. (LM( #& # )*; 60 ∼ 90 &NJ& 1(( "
( <=bc . K/K (LM 01234 ( .& M6 )0$ 5
456 . U 5456 -%& .2$ 4 mm2 . 01234 5456%& 2 × 10−5 Torr
Z 100 nm #23 #$% ITO )0$%& )*S'236-%q., o [=
!, =A/&, , 5564 v yu23 #=bc Branson 2210 sonicator( st
- [=6h . ª", - !" HCl : HNO3( DAO 4 : 1 23 L i%&
4 5 307 ¡ (« :& .
3.3 ' &
(LM B .#$ UV photoluminescence
(PL) &' , . UV PL &' ,
# (LM 'PQ]/& 4[/& @7 (LM( # Z23 !"= #&
# L &NJ& !" "( <=bc - . UV ,%&
HP8453 . (A) L- :;%& #23 !% .
A = − logI
I0
(3.1)
I (LM( - # .GN [= Xd I0 N .GN [=
. "כ! 4\]4(α)( L- :;%& #23 ( 4 .
α =1
dln
I
I0
=1
dln (10A) (3.2)
d (LM Z .
41
PL &' ,%& -% # B .GN (LM S L N
.GN[=( B 7 C , # . EL &'%&"')*; )
!;% U N .GN [=( B 7 C , # #23"כ! )*;
)* LED:; . PL, EL &',%& AMINCO-BowmanSeries
2 Luminescence Spectrometer( . DA .;; +,K
)*; .GN ,( U r/ N 5_0( # Newport
Picowatt Digital Optical Power Meter(model 1830-C)( ,
. DA .;; +,K (ηex)%& o R" :; ( 4 .
ηex =Popteλ
Idhc(3.3)
Popt optical power Xd λ optical power( , #.GNB , Id
"')*; )56, c .GN 234 .
3.4 DC J-V &
DC J-V , O \j )*; ( DA456 J, , j¬6:
: #23 > 4 . ,23 Keithley 237 high voltage
source measurement unit (SMU)( I )0$ .;0 ) @AXd '(
)56( , . j¬6:: 23 GPIB: ( I
SMU( j¬6: S'23PQk@l#23 <=H, ~ :( E . )*; DA456
J \j %- % #23 > 4 . % ¡!"=
# 0PQ(jig)( I . % (LM( CTI-
Cryogenics )I Cryodyne refrigerator sample holder 2% ) BC
%& Cry-Con grease Apiezon grease( I )*; ( sUt .(LM )0$
42
silver paste23 gold wire( DA456 Xd gold wire carbon paste(
Cryostat )0$- !% . )*; > !%?H /-%® Cryostat
& mS'( 0.02 Torr & u0vXd CTI-Cryogenics 8200
Compressor DRC-91CA temperature controller( %( -%
\j K0% %(300 ∼ 10 K) J-V , . b DC
%& .GN v 0 # 1" 4,-J .
3.5 Time of flight &
Time of flight (TOF) , O PQP 3.4 :; \j yz O DA
7, , )23 (LM Xd O DA7#23 > 4 . yz O DA7
%& L- :; . #23 yz Nd-YAG yz 23 .2$ 355
nm .GN @A 10 Hz, n % c 7 ns23 m3W S . (LM O©@A .GN
%& optical power oscillator(OPO)( - # .GN~ .GN B 480 nm23
Xd . OPO( - # yz +( K0% !"
neutral density(ND) filter 1 % , 10 % , 36 % ( I Xd yz -1I
- K0% pin hole I . , )23 DA7 %&
2 kΩ I Xd )56 , Tektronix TDS 3032 oscilloscope( I
. (LM Xd J23 DC U :; % 0PQ( ,
% Cryostat( I . -% # ) )*; @AXd ¤AM
# )0$ yz .GN -1I (« ?0R ) oscilloscope( I
, . )56 , )- , )23 #23DA: \]I (
4 . %, % %& # %(300 ∼ 10 K) -% # 1"
43
) JK @A- )56( , .
TOF L-:;%&op> 0<= #KK/ .6")TU23
, )23 (0 # RC )23 h, 4 Xd GH # )23 ((4 RC
( > & . \ ((4 RC ) '(( (τ) OXY!" '< J
0 , 23 #$o o| # . GH #23_כ כ: 4 kΩ 23 <= #!"
o| UA TU ) 1< 7 #$o o| # . 7 C (LM Z>
7 ZEcao| # . Z )TU23 .GN 4 Z> (LM ) Zk3 o
@A #$o o| # . .GN 4 ' ) > ?0R\j ?Xd GH # ) > (
LM( - # (( , UA (LM Z 4 µm> ?Ho| # .
[=)TU23yz .GN @A(( ) '((k3 o @A#$o o| # .VW
)TU23 @A-1 , ) TU ) ) 1< (CV)k3 o @A #$o o| # .
3.6 AC ! "!" &
AC , QuadTech 7600 LCR meter( I .
, @AB 4 wr%& 10 Hz ∼ 2 MHz Xd 100 V DA DC )
> ( 4 #$% qrDA#23 2 V DC ) 4 . AC )%& DC
)'< 3@A!" 0.2 V ( #$%.GN v 0 #1"
. I # )*; LED K :;# M6 Al )0$ .;
0:L 6 mm  . GPIB : ( I
j¬6: S'23PQk@l#23 <=H, ~ :( E . DA -% # )
!;%HS 1" @AB 4( 10 HzDA: 2 MHzE 0 JK > -
( , .
44
Figure 3.4: TOF .
45
Chapter 4
4.1 '
4.1.1 UV absorbance
PQP 4.1%& MEH-PPV, DHF-PPV w UV (ab-
sorbacne) . PQP 4.1(a)%& MEH-PPV UV PL !%- . UV
> 2 FH0 DA7 (ZW[ scattering#23 # °DA7 <= )- PL
# J> MEH-PPV XYZ !" . PQ כ: 2.2 eV
23 PQP 3.2 -%J # . UV k3- VW\n > .
+#$+#$ J 2.5 eV (I), 3.7 eV (II), 4.8 eV (III), 5.9 eV (IV) . PQP
4.2 :;%& PPV one-electron K GH # ( L %M( 4
[32, 33, 34]. PPV 01< 8\n A/&)* ; > Xd +#$ A/&)* ;
π ); ( > 023 8\n ( ?0R+#$ ( 4 . 4\n )
46
(conduction band), $H0 4\n > ); (valence band)23 5AH
. +#$+#$ "#$)* (L) 3\n O"#$)* (D1,
D2, D3)23 > 4 . "#$)* Xd &%"כ! 01<
); B '.4> +#b¢£ "כ! oQ Xd O"#$)* 7 C $q\j
"כ! # . GH # K> PQP 4.2 . +#$
+#$ I O"#$)* I (D1 −→ D1∗) ) ?0R
$% IV "#$)* I (L1 −→ L1∗) ) ?0RK . (
III "#$)* O"#$)* I (D1 −→ L1∗ 9
L1 −→ D1∗) ) \j . (! !%./0 \j ∼ 0.2
eV, ∼ 0.4 eV, ∼ 1 eV [= > 023 > 4 ~ "#$)* -%4:
!%./0> c0 !%< . > !%./0> # IV
!% Frenkel (!#23 h, 4 [35]. $H0 (! !%
./0 +#$ . v > . II !% III :; "#$)*
O"#$)* I ) (! !%./023 !"
IIIk3 #$%& ./0 > #23"כ! !" ( 4 . 0
- II wr o ]/& , [33, 35]. PQ "'c ,%& A
.& . 4\nwr L %M Xd [36, 37, 38, 39].
PQP 4.1(b)%& DHF-PPVMEH-PPV (copolymer) DHF-
PPV UV . MEH-PPV d/&> 023 VW \n > e" #
. #23 [= \n 4.0 eV (II), 4.4 eV (III), 5.9 eV (IV)( >
0Xd <=-% %& I ./0 3.0 eV (DHF-PPV), 2.9 eV (10:1), 2.7
eV (1:1) כ: > & . [=\n (II, III, IV) 2 F
bc -% # כ: > 0Xd > %& N I J- )- "כ!
47
4 .&'(LM(ZQ-?H .PQP
4.3, 4.4%&+#$+#$( OXY ( xPQR"S' . 4\n
II, III, IV J DHF-PPV Z> 0 bc
)- 0, . IV MEH-PPVE 0PQ:כ )- 0, .
7 C &%"כ! M WX #~23 "#$)* I ) Q-
#23"כ! h, 4 . II !% DHF-PPV Z E 0
J )- > bc 2 F > MEH-PPV .2$ 0.3 eV ?7)- > .
III%& DHF-PPV Z> 0 E 0 o @A #$%& 6@&?7)- >
k3 > MEH-PPV 0.4 eV6@&?7)- > '? . II
)- !%<%& M d/&> 023 "#$)* O"#$)*
I ) Q-#23L %M(4 .O"#$)* 7
C O"#$)* ?H UA '< 5?Xd O"#$)*
!% # & #?H UA '< 3 5? Xd
h, 4 . 0- III 6@&?7)- > -%H !%< %/&wr23
.O"#$)* ± ) # I 3.0 eV (DHF-PPV), 2.9
eV (10:1), 2.7 eV (1:1), 2.5 eV (MEH-PPV) ²4A" # ?7)- > '
. 9 # conjugation T Q- H O"#$)*
'< 5? "כ! 4 . GH # "#$)* O"#$)* +,-(
4\]4 PQR"S' +#$ )- h, 4 .
( :;%& (LM3 OXY!" k3- +#$ wr > (LM
8' . I ( .& (LM OXY!" k3- MEH-PPV> ,o -%4
: ( O!" wr#23 c0 "כ! h, 4 . &%"כ! .;;
./0 XYZ ); 4 %/&Oyu # I - ) -
48
%& ); 4 Oyu # I ( 4 . 7 C MEH-PPV
> ,o -%4: ./0 XYZ #$o 023 I c0 #23"כ!
!" ( 4 .
49
Figure 4.1: UV 4 &'; (a) MEH-PPV, (b) DHF-PPV .
50
Figure 4.2: PPV one-electron K.
51
Figure 4.3: UV 4 &' (a) 6")TU (b) VW)TU
OXY.
52
Figure 4.4: UV 4 &' (a) Z)TU (b) [=)TU
OXY.
53
4.1.2 PL emission spectra
PL &' %& PQP 4.5(a) k3 "כ! DHF-
PPV 516 nm (2.41 eV), (DHF-PPV : MEH-PPV = 10 : 1) 554
nm (2.24 eV),(DHF-PPV : MEH-PPV = 1 : 1) 579 nm (2.15 eV),
MEH-PPV 587 nm (2.12 eV):כ > & כ: . UV
# XYZ- OXY( !"k3- (10:1)- # ?7)- ( k3-%< $H
0O2Q \j-%J 4 "כ! .(10:1)!% UV
k3- DHF-PPV\j .& 2 F 4 "כ! . 0- PL
&' MEH-PPV DHF-PPV( כ:> 4 "כ!0
. \ v %& UV .; ,%& DHF-PPV K0
>? PL &' %& ./0 XYZ > 0 MEH-PPV
K0 '< Xd !"( 4 . 5, *+%& ./01" DHF-PPV
K0 (! %& ./01"( > 0 MEH-PPV
K0M6#23 ' & qr!#23"כh, 4 .PQ%/&!"
(1:1) !% UV PL &' # XYZ :;%& כ:
k3 ~ &%"כ! 7 MEH-PPV K0 .; ,o UV
PL &' ,%& '< J #23"כ! h, 4 .
PQP 4.5(b) +#$+#$ PL &' .; OXY
J( x "כ!. (- # &%"כ! #$1" &' S U
A ?0R H³UDA7 )- . Homopolymer k3 H
³UDA7 !% bc k3 0 , . \ AGB%& DA7#23
conjugation ³U& polymer h, 4 AGB [40, 41]. 7 C
O2Q \j 234 ³U ) * # Xd h, 4 . PQP 3.2
54
h, 4"כ! MEH-PPV DHF-PPVK> 8'XdXYZv
> . C D\j K> .& Z -%23 ( - !%
M # "כ! 234 ³U0\j ?H &'S(vibration state) '
< #$o H³UDA7 H\j?!כ" . GH #Owr:&%&
(! MEH-PPV K0 <= # ' #?\j ( ( 4
~ GH # '< "' +,K BC\j ) * # . <= "' +,K
+,K homopolymerk3 *+ "כ! 4
[42].
55
λ
λ
Figure 4.5: (LM PL &' ; (a) PL &', (b) .;OXY.
56
4.2 DC J-V
4.2.1 MEH-PPV
(
MEH-PPV( # )*; B .#$ HTD
DC J-V . PQP 4.6%& HTD % !%- . PQP 3.2
4 Q Au( # @A-1( )3P #$o )*; )56
( transport limited current(TLC)23 h, 4 . PQP 4.6(a) J-V ~
( 2.12 $O PQ$"= #23"כ! -%J "כ! 4 . 9
# PQP 4.6(b) 2.13( !" O PQ$"= #23"כ! PQP 4.6(a) O!"
) h, 4 . PQP 4.6%& SCLC ) '
) ( # 2.12> . k3 S . GH # > 1%&
log(J)-log(F)$OK > 2( SLCL ) '
( > 1 ) ' ) A> # "כ!. PQP
4.6(a) $O # כ: k3- L- :; .
γ = 2.6 × 10−4 (m1/2 /V1/2)
µ0 = 5.4 × 10−7 (cm2/Vs)
) 1×107 (V/m) ' 1.22 ×10−6 (cm2/Vs)#23 <#S
. GH # 4J:כ%& k3Xd ? !%- O2Q # כ: [43, 44, 45,
48]. b \]I )4(εr) 3#23 *C.#S~ &%"כ! AC
- 45_XdAAyB[45] ( 4 .
57
Figure 4.6: HTD(MEH-PPV) % !%-; (a) PF-SCLC PQR"S', (b)
PF-SCLC I PQR"S'.
58
PQP 4.7%& % 7 .& )56 $O . PQP 4.7(a) k3 "כ!
%> o -%4: )56> -% # )#$o 4 "כ!0 .PQP
4.7(b) 2.12 $O PQ$"=!#23"כ +#$ % כ: ¦ h
4.1st( .¦ h h, 4Q %> qrG%:4: '
> #$o 0Xd ) (γ)> c0 "כ! h, 4 . +#$+#$ %
# µ0 γ % o k3 . LJ [=
2.18, 2.19, 2.20 +#$+#$ PQR"S'( PQ4P .
Gill 2.18 !" ~ ( 7 # PQR"S' PQP 4.8
4.10(a) . Z PQR"S' h, 4 Q µ0 γ T−1 "כ!
4 . 2.18 +#$ כ: !"k3- L- :; .
B = 2.27 × 10−5 (V−1/2m1/2eV) , T0 = 420 K
∆ = 0.48 eV , µ∞ = 69 (cm2/Vs)
L#23 GDM ( 2.19) ~ ( 7 # PQR"S' PQP
4.9(a) 4.10(b) . γOXY# µ0,!כ" 4
. 2.19 +#$ &%כ: L- :; .
σ = 0.095 eV , µ∞ = 8.0 ×10−4 (cm2/Vs)
C = 2.11 × 10−5 (m1/2V−1/2) , Σ = 2.25
08#$#23 CDM ( 2.20) ~ ( 7 # PQR"S' PQ
P 4.9(b) 4.10(b) . M GDM d/&> 023 γ # µ0
3 "כ! 4 . U 2.20 +#$ &%כ: L- :; .
σ = 0.106 eV , µ∞ = 8.0 ×10−4 (cm2/Vs)
Γ = 3.4 , a = 0.56 nm , C0 = 0.78
59
a &%כ: C0> 0.78-%U כ:. 2.22 "#$)* T
(L) - 1.7 A .
γwr #PQR"S'[=Z?# GDM Σ:כ
\j -%J ?0 ,.#S . µ0 wr # PQR"S' T−1 Oyu
#23k3o"כ! 2.18 ~ 4 "כ! .45_XdA[49]-O
XY( !"h, U K> O2Q # OC1C10-PPV ~ I .
:; 2.12( # > 1%& TOF, AC , Transient EL, FET, TSC
(thermally stimulated current) PQ 5M?
[46, 53, 73, 74, 75, 76, 77, 78].
Table 4.1: MEH-PPV % 7 .& DC '.
% 298K 273K 260K 240K 219K
µ0 7.2×10−7 1.2×10−7 3.0×10−8 7.0×10−9 6.6×10−10
γ 2.4×10−4 3.6×10−4 4.0 ×10−4 4.8×10−4 5.8×10−4
% 200K 180K 160K 140K 0
µ0 7.3×10−11 3.5×10−12 7.1×10−14 4.7×10−16 cm2/Vs
γ 6.6×10−4 8.0×10−4 1.0×10−3 1.3×10−3 V1/2/m1/2
60
Figure 4.7: HTD(MEH-PPV) % !%-; (a) I-V !%-, (b) PF-SCLC
PQR"S'.
61
γ
Figure 4.8: HTD(MEH-PPV) % 7 .& γ T−1 PQR"S'.
62
γ
γ
Figure 4.9: HTD(MEH-PPV) % 7 .& γ (a) T−2 PQR"S', (b) T−3/2
PQR"S'.
63
µ
µ
Figure 4.10: HTD(MEH-PPV) % 7 .& µ0 (a) T−1 PQR"S', (b) T−2
PQR"S'.
64
4.2.2 DHF-PPV) כ
PQP 4.11%& DHF-PPV +#$ )*; DC !%- . ETD HTD
)56/-%( OXY!"k3- %/& HTD )56/-%> .2$ 12" ETDk3
> HTD )56> WX!X 5> Xd L ETD )56 :; 5
> # . HTD ETD+#$)*; )56!%< -%J # Xdh, 4 .
L 5> ((I)- WX!X 5> ((II)#23 > 4
. O ( I !% PQR"S' K > 2 3e56#23 ) 5> (4
: K > K01B 5> "כ! h, 4 . ( SCLC23 !" (
!% %& 10−10(cm2/Vs), ); 10−11(cm2/Vs) ) '> \]
I . C D\j \]I ) ' %& ) ' Xd ( I
SCLC23 !"( !% ( II !" >Pd 0 .
PQP 3.2 k3- HTD(Au)!% )3P 0.8 eV, ETD(Al)!%
0.8 eV )3P e" "כ! h, 4 . )3P 0.4 eV
-%U )56( injected limited current (ILC)23h, 4#23 DHF-PPV
)*; )56 ILC23 h, 4 [54]. !% M . L 1Q
( I 2% % # ) @A-1 hopping # ) @A-1, Poole-
Frenkel emission (#23 h, 4 . ( II ) *+o 7
C ) @A-1 WX!X \j 5> ~ &%"כ! :$% L %M( 4 . PQ
P 4.12 k3- Z ((I, II) 7 ( 4 . PQP A/& #
(- K > # (#23 > 4 ~ A/& # DA7 ( I Xd K
> #( :$%& #( II!כ" . 2.504.4DA7-PQ
P 4.12 )3P !"k3- !% 0.73 eV, ); !%
0.63 eV כ: ( 4 . &%כ: .כ: 0.8 eV band bending
65
XdG%!" h, U # #23כ: h, 4 . 0- 2.5 \]I )56/-%
)56/-% O!" #$%& כ: k3 ~ &%"כ! backflow )5623
# "כ! [55, 56].
LED )56/-% HTD )56/-%k3 .2$( #$ > )
2×107 (V/m) ( ]H#- HTD )56k3 \j 5> "כ!
h, 4 . HTDk3 )56> .2$( #$%& &%"כ! @A-1 HTD
Auk3 -%.4> #$%& ITO # "כ! UA . U LED )56
> HTD )56 O2Q # #23"כ! k3o # )56C "כ! 4
. ) *+o 7 C )56> HTD )56k3 c0 "כ! h, 4
~ &%"כ! ); > J!X#23 @A-1? (#$!" - . ?
UA [8, 57].
(copolymer)!%MLJ DHF-PPVO2Q # )56
k3 .PQP 4.13h, 4Q %/& HTD )56> LED
)56k3 )* \j , > ) 5> . 7 C LED )56> ,\j
. ETD )56 > %& כ: k3 . 7 C LED +,K ‘
- ); _(&’ C 1 U ); +,K @A-1 _כ#
KK/ 4 [58, 59, 60].
66
Figure 4.11: DHF-PPV DC !%-.
67
Figure 4.12: FN :$%& # DHF-PPV DC PQR"S'; (a) HTD, (b)
ETD.
68
Figure 4.13: DC !%-; (a) DHF-MEH (10 : 1), (b) DHF-
MEH (1 : 1).
69
4.2.3 LiF *
"')*; +,K *+ # > 1 , > 1#23
, K( # "כ! . ,K -%%& k3
); @A-1, 423 ( \j ./0 S ) '>
BC%& -% # . 0- LiF, SSPS, PMMA, Al2O3 XYZ
# DA( # K ,K .& 0pXd
[62, 65, 66]. GH # o k3 MEH-PPV DHF-PPV
(DHF-PPV : MEH-PPV = 10 : 1)( # LED, ETD DC J-V
. LED!%K ITO/"',/LiF(5A)/Al Xd ETDK
Al/"',/LiF(5A)/Al . LiF Z A > +,K
BC Xd k3Xd 5 A [61]. PQP 4.14 LED ETD DC
!%- . LED !% %/& )56/-%> bc :; > ) 5> -
LiF( # )*; )56/-%> µ c0 "כ! h, 4 . 7 C
LED LiF, 7 # ) @A-1( "כ! 4 . ETD
LiF( )*; > 150 MV/m E 0 )56/-%> #$ > PQ
)56/-%> WX!X 5> "כ! 4 . :#23DA"כ! ETD
LiF, 01#23 ); @A-1 v0 P'Q # "כ! 4 .
0- *+%& ) :$%& # ) @A-1 YUL @AXd "כ!
#23 k3 . PQP 4.14(b) R-LiF-ETD PQR"S' LiF> )0$ .;
0$#23 Xd%/&wrM6 )0$ L0$#23 #23"כ!# LiF23 # ) <= #
+,-( k3 # "כ!. !%> )56/-%> > #$%& #23"כ! k3o "'
, %/&wrM6 )0$ @A-1 ); > LiFM6 )0$#23 NGH > "כ! +,
-#23 8#$o S "כ! 4 . ); d/&> 023 LiF,
70
!" <= # +,-> "כ!. LED ETD !%-23DA: LiF
( XdG%!"k3- L- :;%& !%. ZWkH HI 4 . O !%
LiF,#23 !" "', , $HGH 4 Xd C D\j L0$M6
z$"= %& ); > :$%&!"o| )3P AH ); :$%&
v #23"כ! ?0R+#$ [62, 63].
LiF :;%& DA( # )*; DA.;; +,K 5> AGB
, k3Xd? [61, 62, 64, 65]. GH # AGB%& \j )56_(&+,- )
0$- "',I \]- +,-23 H ?0R+#$( 4 . k3 0, K
)*; !% )56> ); )56k3 # #23"כ! G% . M
!%- h, 4 Q LiF ); @A-1 5> (« )56 _(&
# Xdh, 4 . L#23\]-+,-wr!"?0R+#$!"k3-DA
LiF Al- "', I "'?0R !% 8#$o @A ( # [67].
"', Al 01 5456 - 01- quenching site> ?0R\j .
quenching site 01#23 PL +,K (* [68]. 7 C LiF
\ quenching site "'?0R 8#$o fa +,K BC\j "כ!. 0- LiF
:;%& DA !% ); :$%& !" @A-1? UA Ca :;%&
-%.4> 7 Xd :P¤A %& )0$k3 +,K BC0 P'Q # #23"כ!
?0R+#$ [69, 70].
71
Figure 4.14: LiF, # DC !%-; (a) LED, (b) ETD.
72
4.3 Time of flight
(
MEH-PPV( time of flight (TOF) . PQP 4.15%&
MEH-PPV UV~ 3.2 #4\]4(α)
. TOFI #yz B 490 nm4\]4 24.7 µm−1
. 4\]4( 90%4?Z( \]I!"k3- 932 A .7
C TOF )*; Z 1 µm Ho| # . PQP 4.16%&
Z 1.7 µm ) 70 V( > # TOFPQR"S' . .L
J PQP 2.3 :;%& TOF PQR"S'( E 4 . PQP 2.3(b) %/&
K αi ) c0- .2$(B H # PQ )- 50 VDA:
100 VE 0 0.968 ∼ 0.946 23 # )- > 2 FXd, 110 V 0.896 כ:
k3 .PQ%/&!"lm%/&K αf:כ%& 50DA: 100 VE 0 0.118 ∼1.32 23 5> > 110 V 2.63 כ: k3 . αf:כ%& )
c0- 5> # αi &%כ: ) c0- #$o r .
GH # !%<%& 2.31- 0 , . 9 # αi &%כ: bc 1 > 9Xd )-
> 100 VE 0 bc 2 F . GH # K 7I (dispersion) 2 F
) ' - I [71]. αf !%<%& )56 !%<#
23 L %M( 4 . ) c0- .#= )56 (dark current)> c0~
'( )56c0\j .7 C c-<#$cc0 כ:56(
αf כ: 5> \j ? "כ!. !%-#23 ) αi, αf !%
<%& 2.31 7 8'0 , "כ! 4 .
73
PQP 4.17%& ' ) ( k3S . PQR"S' log(µ)–
F1/2 wr "כ! 4 . PQP 4.17 ' )
(γ) µ0 &%כ: L- :; .
γ = 4.56 × 10−4 (m1/2/V1/2)
µ0 = 4.99 × 10−7 (cm2/Vs)
"כ! !" ) 1×107 (V/m) '( - 2.11×10−6
(cm2/Vs) . ' &%כ: DC # -כ: bc O2Q $%
γ, µ0 כ: I # כ: k3 . 7 C DC J-V # '>
4 "כ! .9 # )56&'789 #+,-k3
Poole-Frenkel +,-> "כ! 4 . # '
2.28 $% γeh כ: 1.27 × 10−8 (m−3/s) 4 .
74
α µ
λ
Figure 4.15: MEH-PPV 4\]4.
75
Figure 4.16: 70 V TOF !%-; (a) linear PQR"S', (b) log-log PQR"S'.
76
µ
Figure 4.17: ' F1/2 .
77
PQP 4.18(a) TOF% !"E%& '+#$%
) ( 12S PQR"S' . %> qrG%:4: '> sC%
H0- ) (γ)> c0 "כ! h, 4 . +#$ % µ γ
&%כ: ¦ h 4.2 . TOF ¦ h כ: DC # ¦ h 4.1- O
XY!" k3- µ0 γ:כ v 2" 23 O2Q # כ: k3 4 . PQP
4.18 (b) 4.20%& Gill 2.18 ~ ( !" # #23"כ! +#$ כ:
!"k3- L- :; .
B = 3.3 × 10−5 (V−1/2m1/2eV) , T0 = 438 K
∆ = 0.48 eV , µ∞ = 12 (cm2/Vs)
+#$ &%כ: DC -כ: µ∞> .2$ 6" v > < O2Q "כ!
4 . L#23 GDM( 2.19) ~ ( 7 # PQR"S' PQ
P 4.19 (a) 4.20 (b) . U 2.19 +#$ &%כ: L- :; .
σ = 0.112 eV , µ∞ = 4.12×10−3 (cm2/Vs)
C = 3.05 × 10−5 (m1/2V−1/2) , Σ = 2.36
~ ( DC ~ OXY!"k3- µ∞> .2$ 5" v >
< $H0 &%כ: O2Q "כ! 4 . 08#$#23 CDM( 2.20)
~ ( 7 # PQR"S' PQP 4.19(b) 4.20(b) . U
2.20 +#$ &%כ: L- :; .
σ = 0.125eV , µ∞ = 4.12 ×10−3 (cm2/Vs)
Γ = 5.33 , a = 1.2 nm , C0 = 0.78
78
a &%כ: C0> 0.78-% U כ:. 2.22 "#$)* T
(L) - 7 A . &%כ: DC # -כ: .2$ 4" v >
. GDM- d/&> 023 µ∞- v > < .& &%כ: O2Q # "כ!
4 . PQR"S' [= Z "כ! 4 . [= >
0 Z DC # -כ: O2Q # כ: k3 . !%-#23 DC
# '( TOF ( 4 .
Table 4.2: MEH-PPV % 7 .& TOF '.
% 308K 296K 278K 260K 240K 0
µ0 1.7×10−6 6.5×10−7 2.3×10−7 6.4×10−8 8.8×10−9 cm2/Vs
γ 3.5×10−4 4.4×10−4 5.1 ×10−4 5.8×10−4 7.2×10−4 m1/2/V1/2
79
γ
µ
Figure 4.18: TOF23 # '%; (a)%7 .& )
, (b) γ T−1 .
80
γ
γ
Figure 4.19: γ (a) T−2 , (b) T−3/2 .
81
µ
µ
Figure 4.20: µ0 (a) T−1 , (b) T−3/2 .
82
4.4 AC ! "!"
DHF-PPV( "',#23 I # LED( AC
DA ) -% \j S 1" . PQP 4.22%& 0 ∼ 8 VE 0 DA
) !%- . PQP 4.22(a) @AB 47 C ,
( )*-PQ$"=PQR"S' . PQP(DA7K .2$ 0.5
. :#23DA"כ! PQR"S'( O PQ4P !% %/& % "כ!
4 .7 C )*; > )23> 345 RC 4 "כ!23( [27].
"כ! !" k3 DA ) 7 V-% U AC , !%-
( PQP 4.21(a) :;%& > )23( PQ+G5 4 . PQP- :;%& 3
45 RC )23 L- :; .
Z = (1/G) · 1 − jwτ
1 + ω2τ 2(4.1)
1/G R- :;Xd τ RC :; . 345 RC )23 4523 #$%&
(RsR0) sUt!% L-:;%&+,*/+!, (effective conductance)
G(ω) +, TU ) )1< (effective capacitance) C(ω)(
4.1 ( 4 .
G(ω) = G01 + ω2τ 2/b
1 + ω2τ 2
(4.2)
C(ω) = C01
1 + ω2τ 2
b RsG0 Xd τ RsC0 .PQP 4.21(b)> )23 4.1, 4.2
$O PQ$"= #23"כ! ~ -%J "כ! h, 4 .
> )23 45 %& .2$ 11 Ω#23 ITO )0$ [81].
45 %& bulk 617 Ω O #$%& "כ! 4 . Bulk
83
- 45 45_XdA[80] Z> O2Q Xd )*; K(ITO/MEH-
PPV/Al)> :;%& MEH-PPV OXY!" 1 U 0 V bulk %& .2$ 30
MΩ#23 DHF-PPV O2Q . 0- 45 %& DHF-PPV )*; > 1/4
23 #$ . (0 \ > )23- 1 U )*; DC )56 MEH-
PPV DHF-PPV> O2Q!"o| # . 0- DC !%- <#SQ
DHF-PPV )56> 1000" #$\j N "כ! 4 . 7 C
DHF-PPV )56 ) 3Pv > c injected limited current
(ILC) ( 4 .
PQP 4.22(a) %M6 ZW[ 4&%(Z′)כ: 45(Rs)#23
)- 2 F -% . bulk (R0)%& PQR"S' 0:L- :;%& כ:
.PQR"S'h, 4Q bulk%& DA )7 C PQ:כ #$o & .
TU ) )1<(C)%& DA )7 C bc)- 0,.#S .PQP 4.22(b)
PQR"S' ) 5> . 7 C @AB 4> N.&M6#23 '
"כ! 4 . @AB 4(fc) 345 RC )23 o R" :;
%& \]> .
fc =1
2π
1
RC=
1
2π
G
C
PQP 4.21(b) ¢¶4(Z′′)כ: @AB 4( > & . PQP
4.23(a) fc TU ) )1< (C), */+!, (G) PQR"S' . PQR"S'
k3 Q C fc2 F bc-% Xd fc GOyu\](fc ∝ G)
"כ! 4 . 7 C fc )- DA ) *+o 0- R (G)
)- - -%H AGB . )56/-% (J) J ∝ GF \]> #
23 "כ! - PQR"S' 4.23(b)( PQ+G5 4 . PQR"S' %/&
K 1.5 Xdlm%/&K 7.823 DC K )-
84
I "כ! 4 . 7 C fc )56/-% )- 7 .&
"כ! ( 4 [80].
85
Ω
Ω
Ω
Figure 4.21: 7 V LED(DHF-PPV) (a) > )23 (b) .
86
ω
Ω
Ω
Figure 4.22: LED(DHF-PPV) AC !%-; (a) )*, (b)
)\]4 ¢¶4DA7.
87
Figure 4.23: fc 7; (a) fc G, C \], (b) F-GF PQR"S'.
88
Chapter 5
GH PPV "')*; wr
B .#$ ( 4 . O PPV K
wr!" ( 4 . UV (absorbance) DHF-PPV
MEH-PPV, (copolymer) +#$ )- !%<
. L %M( 4 #$% PL (!
"#$)* +,- (10:1) (! %& ./0 1"23 '
"כ! 4 . DC MEH-PPV HTD )56/-% $O%&
) ' )(Poole-Frenkel+,-)-&'789 2 F SCLC
4"= 2.12234 4 .9 # # DC
' TOF # '> %> o -%4:#$o 0Xd )
(γ):כ %> o -%4:5> !%< 23:;.#S . µ0
γ:כO2Q. 4 .7 C MEH-PPV HTD )56 transport
limited current (TLC) "כ! ( 4 . )3P # DHF-PPV
89
)56/-% !%<%& ) #$ U %& ) @A-1 k3 > )
c0-:$%& # ) @A-1 k3 injection limited current
(ILC) tgu 4 . 9 # LED )56 )
U # )56> @A( 5A > ); > @A-1?- HTD )56k3
c0 "כ! ( 4 . Z > 0 DHF-PPV O2Q #
!%< k3 "כ! 4 . LiF,- (10:1)( # DC
DA, # )*; )56 5> <= #- );
:$%& 5> (F #$' wr 4 . MEH-PPV(
# TOF !" 01#23 '( ( 4 #$% % wr
# ' !%<- ) (γ) !%< B .#$( 4 .
9 # TOF DC # ' (
4 . DHF-PPV( # AC )*; > )
23( ( 4 . DHF-PPV > )23 45_XdAAyB[80] MEH-PPV
> )23 OXY( DHF-PPV )56> ILCC "כ! ( 4
. 9 # DA ) 7 .& */+!, (G) )- ) \]
4 (electric modulus) ¢¶4כ: )- ( '( 4 . GH
# )- DC J-V )56/-% !%<- :;L 4 .
90
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