Browsing by Author "Li, Yongfang"

Now showing 1 - 7 of 7

Combination of Indene-C(60) Bis-Adduct and Cross-Linked Fullerene Interlayer Leading to Highly Efficient Inverted Polymer Solar Cells
(2010-12-15)
Cheng, Yen-Ju
;
Hsieh, Chao-Hsiang
;
He, Youjun
;
Hsu, Chain-Shu
;
Li, Yongfang
A poly(3-hexylthiophene) (P3HT)-based inverted solar cell using indene-C(60) bis-adduct (ICBA) as the acceptor achieved a high open-circuit voltage of 0.82 V due to ICBA's higher-lying lowest unoccupied molecular orbital level, leading to an exceptional power-conversion efficiency (PCE) of 4.8%. By incorporating a cross-linked fullerene interlayer, C-PCBSD, to further modulate the interface characteristics, the ICBA:P3HT-based inverted device exhibited an improved short-circuit current and fill factor, yielding a record high PCE of 6.2%.
Combination of Indene-C-60 Bis-Adduct and Cross-Linked Fullerene Interlayer Leading to Highly Efficient Inverted Polymer Solar Cells
(2010-12-15)
Cheng, Yen-Ju
;
Hsieh, Chao-Hsiang
;
He, Youjun
;
Hsu, Chain-Shu
;
Li, Yongfang
A poly(3-hexylthiophene) (P3HT)-based inverted solar cell using indene-C-60 bis-adduct (ICBA) as the acceptor achieved a high open-circuit voltage of 0.82 V due to ICBA's higher-lying lowest unoccupied molecular orbital level, leading to an exceptional power-conversion efficiency (PCE) of 4.8%. By incorporating a cross-linked fullerene interlayer, C-PCBSD, to further modulate the interface characteristics, the ICBA:P3HT-based inverted device exhibited an improved short-circuit current and fill factor, yielding a record high PCE of 6.2%.
Efficient solar cells based on a new polymer from fluorinated benzothiadiazole and alkylthienyl substituted thieno[2,3-f]benzofuran
(2015-05-01)
Cui, Ruili
;
Zou, Yingping
;
Xiao, Lu
;
Hsu, Chain-Shu
;
Keshtov, Mukhamed L.
A new conjugated D-A copolymer, TBFBT, containing a fluorinated benzothiazole electron-acceptor unit and an electron-donor segment of alkylthienyl substituted thieno[2,3-f]benzofuran, was synthesized using a Stille coupling reaction. The resulting copolymer was characterized by elemental analysis, GPC, TGA, UV-Vis absorption spectroscopy and cyclic voltammetry measurements. The copolymer was readily dissolved in common organic solvents, exhibited good film forming properties and displayed a broad absorption from 300 nm to 800 nm with a low optical bandgap of 1.56 eV. Cyclic voltammetry measurement gave HOMO and LUMO energy levels of -5.11 eV and -3.49 eV, respectively. Polymer solar cells based on TBFBT: PC61BM (1:1.5, w/w) demonstrated an initial power conversion efficiency (PCE) of 4.1% with a V-OC of 0.72 V and a J(SC) of 11.6 mA cm(-2). PSCs based on TBFBT:PC71BM (1:1.5, w/w, 3 vol% 1,8-diiodooctane as additive) were further optimized by using methanol. The optimized result exhibited a high PCE up to 6.1% with a high J(SC) of 14.4 mA cm(-2) and FF of 0.62, under the illumination of AM1.5G, 100 mWcm(-2). These investigations indicate that the new copolymer TBFBT is a promising donor material for PSCs and methanol treatment is a simple and effective way to improve PCE. (C) 2015 Elsevier Ltd. All rights reserved.
Enhanced Performance and Stability of a Polymer Solar Cell by Incorporation of Vertically Aligned, Cross-Linked Fullerene Nanorods
(2011)
Chang, Chih-Yu
;
Wu, Cheng-En
;
Chen, Shih-Yung
;
Cui, Chaohua
;
Cheng, Yen-Ju
Fluorinated heptacyclic carbazole-based ladder-type acceptors with aliphatic side chains for efficient fullerene-free organic solar cells
(2019-05-01)
Chen, Tsung-Wei
;
Hsiao, Yu-Tang
;
Lin, You-Wei
;
Chang, Chia-Chih
;
Chuang, Wei-Tsung
Molecular engineering of non-fullerene acceptors (NFAs) is a promising strategy to uncover new structure-property relationships and design principles for developing next-generation high performance n-type materials. Two dithienocyclopentacarbazole (DTC)-based NFAs, DTC(4R)-IC and DTC(4R)-4FIC, are synthesized to elucidate the effects of incorporating aliphatic side chains and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) end groups on the thermal and optoelectronic properties of these NFAs. An inverted organic solar cell architecture of ITO/ZnO/J71:NFA/MoO3/Ag is employed. By replacing the phenyl-based side chains with aliphatic side chains on the carbon bridges of the carbazole-based core, the device containing DTC(4R)-IC exhibits an enhanced PCE of 9.61%, a V-OC of 0.94 V, a J(SC) of 16.44 mA cm(-2), and a FF of 62.00%, whereas the device containing DTC(4Ph)-IC exhibits a PCE of 7.76%. The incorporation of 2FIC end groups affords DTC(4R)-4FIC featuring better device performance relative to DTC(4R)-IC, a more red-shifted absorption edge, and a broader absorption range upon fluorination. Notably, the device fabricated with DTC(4R)-4FIC affords a V-oc of 0.82 V, a J(sc) of 18.92 mA cm(-2), a FF of 70.22% and a highest PCE of 10.89%, which is by far the highest PCE for NFA containing heptacyclic carbazole cores.
Incorporation of Fluorine onto Different Positions of Phenyl Substituted Benzo[1,2-b:4,5-b ']dithiophene Unit: Influence on Photovoltaic Properties
(2015-07-14)
Yuan, Jun
;
Zou, Yingping
;
Cui, Ruth
;
Chao, Yi-Hsiang
;
Wang, Zaiyu
We have designed and synthesized two low bandgap conjugated copolymers containing alternating meta-fluoro-p-alkoxyphenyl- (m-FPO-) or p-fluoro-m-alkoxyphenyl- (p-FPO-) substituted benzodithiophenes-co-benzooxadiazole (BO), named PBO-m-FPO and PBO-p-FPO. The properties, including UV-vis absorption, charge mobility and photovoltaic performance of the two polymers have been intensively investigated. The results indicated that the introduction of fluorine atom at m, p positions of phenyl substituted benzodithiophene unit hardly affected their absorption spectra and highest occupied molecular orbital (HOMO) level. However, the two polymers showed different photovoltaic properties. Power conversion efficiencies (PCEs) based on the device structure of ITO/PEDOT:PSS/polymer:PC71BM/Ca/Al demonstrated a large distinction (5.9% for PBO-m-FPO vs 2.8% for PBO-p-FPO) at optimal weight ratio. When replacing the Ca layer with zirconium acetylacetonate (ZrAcac), using 3% 1,8-diiodooctane (DIO) as the active layer additive, the PCEs of PBO-m-FPO and PBO-p-FPO increased by 36% (8.0% vs 5.9%) and 85% (5.1% vs 2.8%), respectively. The active layer\'s mobilities, morphology and molecular packing resulted in a significant difference in short-circuit current density (J(sc)) and fill factor (FF).
Single-Junction Organic Solar Cell Containing a Fluorinated Heptacyclic Carbazole-Based Ladder-Type Acceptor Affords over 13% Efficiency with Solution-Processed Cross-Linkable Fullerene as an Interfacial Layer
(2019-08-28)
Chen, Tsung-Wei
;
Chang, Chia-Chih
;
Hsiao, Yu-Tang
;
Chan, ChoonKee
;
Hong, Ling
In this article, a fluorinated heptacyclic dithienocyclopentacarbazole (DTC)-based non-fullerene acceptor (NFA), DTC(4Ph)-4FIC, is synthesized and blended with J71, PBDB-T, and PBDB-TF, featuring complementary absorption and well-matched energy levels. The DTC(4Ph)-4FIC neat film exhibits face-on preference, whereas the nonfluorinated counterpart, DTC(4Ph)-IC, exhibits edge-on preference; this unique feature owing to fluorination in DTC-based NFAs is observed for the first time. More importantly, DTC(4Ph)-4FIC exhibits improved power conversion efficiencies (PCEs) of 10.92 and 10.41% in J71- and PBDB-T-containing devices, while the devices that employed DTC(4Ph)-IC afford PCEs of 7.76 and 9.48%, respectively. Because PBDB-TF is known to exhibit lower energy levels than J71 and PBDB-T, the corresponding device affords a V-OC of 0.95 V, a J(SC) of 18.29 mA cm(-2), a FF of 75.70%, and a PCE of 13.15%, which is 20 and 26% higher than J71- and PBDB-T-containing devices. Furthermore, the inverted device containing the PBDB-TF:DTC(4Ph)-4FIC blend is fabricated using cross-linkable fullerene (C-PCBSD) as the cathode interlayer, affording a decent PCE of 13.36%, with a V-OC of 0.94 V, a J(SC) of 20.20 mA cm(-2), and a FF of 70.42%.