Browsing by Author "Ding, Ping"

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A High-Mobility Low-Bandgap Copolymer for Efficient Solar Cells
(2010-12-15)
Ding, Ping
;
Chu, Cheng-Che
;
Liu, Bo
;
Peng, Bo
;
Zou, Yingping
A new high-mobility low-bandgap polymer, PBDT-DODTBT, based on benzodithiophene and 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl) benzothiadiazole has been synthesized through a standard Stille coupling reaction. The polymer is soluble in common organic solvents, such as chloroform, tetrahydrofuran, and chlorobenzene and has excellent film forming properties. Preliminary studies of the copolymer showed the charge mobility as high as 7.15 x 10(-3) cm(2).V(-1). s(-1) from SCLC measurement. Initial photovoltaic cells based on the composite structure of ITO/PEDOT: PSS/PBDT-DODTBT: (alpha)PC(71)BM (1:2)/Ca/Al showed an open-circuit voltage of 0.76 V, a power conversion efficiency of 4.02%, and a short-circuit current of 8.96mA.cm(-2).
Effects of thiophene units on substituted benzothiadiazole and benzodithiophene copolymers for photovoltaic applications
(2012-09-05)
Ding, Ping
;
Zou, Yingping
;
Chu, Cheng-Che
;
Xiao, Dequan
;
Hsu, Chain-Shu
Two conjugated copolymers, poly{4,7-[5,6-bis(octyloxy)]benzo(c)(1,2,5)thiadiazole-alt-4,8-di(2-ethylhexyloxyl)benzo[1,2-b:3,4-b]dithiophene} (P1) and poly(2-{5-[5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo(c)(1,2,5)thiadiazol-7-yl] thiophen-2-yl}-4,8-di(2-ethylhexyloxyl)benzo(1,2-b:3,4-b)dithiophene) (P2), composed of benzodithiophene and 5,6-dioctyloxybenzothiadiazole derivatives with or without thiophene units were synthesized via a Stille cross-coupling polymerization reaction. These copolymers are promising for applications in bulk heterojunction solar cells because of their good solubility, proper thermal stability, moderate hole mobility, and low band gap. The photovoltaic properties of these copolymers were investigated on the basis of blends of the different polymer/(6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) weight ratios under AM1.5G illumination at 100 mW/cm2. The device with indium tin oxide/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)/P2:PC71BM (1 : 2 w/w)/Ca/Al gave a relatively better photovoltaic performance with a power conversion efficiency of 1.55%. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
New Low Bandgap Conjugated Polymer Derived from 2, 7-Carbazole and 5, 6-Bis(octyloxy)-4, 7-di(thiophen-2-yl) Benzothiadiazole: Synthesis and Photovoltaic Properties
(2012-01-05)
Ding, Ping
;
Chu, Cheng-Che
;
Zou, Yingping
;
Xiao, Dequan
;
Pan, Chunyue
To develop conjugated polymers with low bandgap, deep HOMO level, and good solubility, a new conjugated alternating copolymer PC-DODTBT based on N-9'-heptadecanyl-2,7-carbazole and 5, 6-bis(octyloxy)-4,7di(thiophen-2-yl) benzothiadiazole was synthesized by Suzuki cross-coupling polymerization reaction. The polymer reveals excellent solubility and thermal stability with the decomposition temperature (5% weight loss) of 327 degrees C. The HOMO level of PC-DODTBT is -5.11 eV, indicating that the polymer has relatively deep HOMO level. The hole mobility of PC-DODTBT as deduced from SCLC method was found to be 2.03 x 10(-4) cm(2)/Versus Polymer solar cells (PSCs) based on the blends of PC-DODTBT and [6,6]-phenyl-C(71)-butyric acid methyl ester (PC(71)BM) with a weight ratio of 1:2.5 were fabricated. Under AM 1.5 (AM, air mass), 100 mW/cm(-2) illumination, the devices were found to exhibit an open-circuit voltage (V(oc)) of 0.73 V, short-circuit current density (J(sc)) of 5.63 mA/cm(-2), and a power conversion efficiency (PCE) of 1.44%. This photovoltaic performance indicates that the copolymer is promising for polymer solar cells applications. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 99-107, 2012