Indeno[1,2-b]fluorene-based novel donor–acceptor conjugated copolymers

2017 ◽  
Vol 30 (2) ◽  
pp. 192-201 ◽  
Author(s):  
Ying Sun ◽  
Xiaojing Ding ◽  
Xueqin Zhang ◽  
Qizan Huang ◽  
Baoping Lin ◽  
...  
Keyword(s):  
Photovoltaic Performance ◽  
Hole Mobility ◽  
Molecular Geometry ◽  
Strong Electron ◽  
Photovoltaic Properties ◽  
Polymer Backbone ◽  
Photovoltaic Efficiency ◽  
Donor Acceptor ◽  
Electron Deficiency ◽  
Conjugated Copolymers

A series of conjugated copolymers based on indeno[1,2-b]fluorene as donor unit with different acceptor units have been synthesized to explore the influences of molecular backbone planarization and acceptor electronegativity on charge transport and photovoltaic properties. Polymer incorporating 2,3-diphenylquinoxaline acceptor moiety shows poor light-harvesting capacity and inferior photovoltaic efficiency of 0.5% due to twisted geometry. By introducing the stronger acceptor thiadiazolo[3,4-c]pyridine in polymer, intramolecular charge transfer is enhanced, giving rise to improved absorption property and photovoltaic efficiency of 1.39%. However, the polymer backbone is still twisted. When thiophene-flanked diketopyrrolopyrrole (DPP) is incorporated as electron acceptor, the polymer exhibits a more planar molecular geometry, yielding a broader and red-shifted absorption spectrum as well as a significantly improved hole mobility of 1.46E-2 cm2 V−1 s−1. However, the photovoltaic device efficiency is only enhanced to be 1.69%. The low-lying lowest unoccupied molecular orbital of −3.95 eV as a result of the strong electron deficiency of the DPP unit may lead to the inefficient charge dissociation and increase the charge recombination, which may give rise to the limit photovoltaic performance.

scholarly journals Synthesis and Photovoltaic Effect of Electron-Withdrawing Units for Low Band Gap Conjugated Polymers Bearing Bi(thienylenevinylene) Side Chains

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1461 ◽  
Author(s):  
Jianfeng Li ◽  
Yufei Wang ◽  
Ningning Wang ◽  
Zezhou Liang ◽  
Xu Wang ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Open Circuit Voltage ◽  
Photovoltaic Effect ◽  
Photovoltaic Performance ◽  
Hole Mobility ◽  
Open Circuit ◽  
Photovoltaic Devices ◽  
Good Thermal Stability ◽  
Highest Occupied Molecular Orbital ◽  
Donor Acceptor

A novel (E)-5-(2-(5-alkylthiothiophen-2-yl)vinyl)thien-2-yl (TVT)-comprising benzo[1,2-b:4,5-b’]dithiophene (BDT) derivative (BDT-TVT) was designed and synthetized to compose two donor-acceptor (D-A) typed copolymers (PBDT-TVT-ID and PBDT-TVT-DTNT) with the electron-withdrawing unit isoindigo (ID) and naphtho[1,2-c:5,6-c′]bis[1,2,5]thiadiazole (NT), respectively. PBDT-TVT-ID and PBDT-TVT-DTNT showed good thermal stability (360 °C), an absorption spectrum from 300 nm to 760 nm and a relatively low lying energy level of Highest Occupied Molecular Orbital (EHOMO) (−5.36 to –5.45 eV), which could obtain a large open-circuit voltage (Voc) from photovoltaic devices with PBDT-TVT-ID or PBDT-TVT-DTNT. The photovoltaic devices with ITO/PFN/polymers: PC71BM/MoO3/Ag structure were assembled and exhibited a good photovoltaic performance with a power conversion efficiency (PCE) of 4.09% (PBDT-TVT-ID) and 5.44% (PBDT-TVT-DTNT), respectively. The best PCE of a PBDT-TVT-DTNT/PC71BM-based device mainly originated from its wider absorption, higher hole mobility and favorable photoactive layer morphology.

scholarly journals Steady Enhancement in Photovoltaic Properties of Fluorine Functionalized Quinoxaline-Based Narrow Bandgap Polymer

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 54 ◽  
Author(s):  
Zhonglian Wu ◽  
Huanxiang Jiang ◽  
Xingzhu Wang ◽  
Lei Yan ◽  
Wei Zeng ◽  
...  
Keyword(s):  
Fill Factor ◽  
Polymer Solar Cells ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Hole Mobility ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Promising Candidate ◽  
Photovoltaic Properties ◽  
Narrow Bandgap

To investigate the influence of fluoride phenyl side-chains onto a quinoxaline (Qx) unit on the photovoltaic performance of the narrow bandgap (NBG) photovoltaic polymers, herein, two novel NBG copolymers, PBDTT-DTQx and PBDTT-DTmFQx, were synthesized and characterized. 2-ethylhexylthiothiophene-substituted benzodithiophene (BDTT), 2,3-diphenylquinoxaline (DQx) [or 2,3-bis(3-fluorophenyl)quinoxaline (DmFQx)] and 2-ethylhexylthiophene (T) were used as the electron donor (D) unit, electron-withdrawing acceptor (A) unit and π-bridge, respectively. Compared to non-fluorine substituted PBDTT-DTQx, fluoride PBDTT-DTmFQx exhibited a wide UV-Vis absorption spectrum and high hole mobility. An enhanced short-circuit current (Jsc) and fill factor (FF) simultaneously gave rise to favorable efficiencies in the polymer/PC71BM-based polymer solar cells (PSCs). Under the illumination of AM 1.5G (100 mW cm−2), a maximum power conversion efficiency (PCE) of 6.40% was achieved with an open-circuit voltage (Voc) of 0.87 V, a Jsc of 12.0 mA cm−2 and a FF of 61.45% in PBDTT-DTmFQx/PC71BM-based PSCs, while PBDTT-DTQx-based devices also exhibited a PCE of 5.43%. The excellent results obtained demonstrate that PBDTT-DTmFQx by fluorine atom engineering could be a promising candidate for organic photovoltaics.

Effect of carbon hybridization in 9H-fluorene unit on the photovoltaic properties of different fluorene-based conjugated polymers

2017 ◽  
Vol 30 (6) ◽  
pp. 677-687
Author(s):  
Zhiguan Lin ◽  
Gang Wei ◽  
Ling Li ◽  
Zhenhuan Lu ◽  
Jiefeng Hai ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Photovoltaic Properties ◽  
Absorption Energy ◽  
Narrow Bandgap ◽  
Donor Acceptor ◽  
Optical Bandgaps ◽  
Fine Tune

To investigate the effect of different carbon hybridization in 9H-fluorene on the resultant polymers, a series of donor–acceptor conjugated polymers have been synthesized by copolymerizing substituted 9H-fluorenes with triazoloquinoxaline. All polymers exhibit good solution-processability and broad absorption in 350–1000 nm region with narrow optical bandgaps ranging from 1.27 eV to 1.55 eV. The results indicate that fluorene functionalization via different carbon hybridization on 9-position could be an effective strategy to fine-tune the absorption, energy levels, and photovoltaic performance of the polymers. 9-Position sp2-hybridized carbon in fluorene could enhance absorption of ultraviolet-visible and form good morphology of blending layers, through its planar rigid structure. All polymer solar cells devices exhibited moderate performance with the best power conversion efficiency of 3.02% achieved based on P2. Compared to ladder-type multifused fluorene, carbon-hybridized 9H-fluorene units can be a very useful building block for constructing narrow bandgap polymers with facile synthesis, and even interesting optoelectronic properties.

scholarly journals Fluorination Effect for Highly Conjugated Alternating Copolymers Involving Thienylenevinylene-Thiophene-Flanked Benzodithiophene and Benzothiadiazole Subunits in Photovoltaic Application

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 504 ◽  
Author(s):  
Lili An ◽  
Yubo Huang ◽  
Xu Wang ◽  
Zezhou Liang ◽  
Jianfeng Li ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Photovoltaic Performance ◽  
Orbital Energy ◽  
Optoelectronic Property ◽  
Polymer Backbone ◽  
Dissociation Probability ◽  
Solid Film ◽  
Microstructural Morphology ◽  
Donor Acceptor ◽  
The Impact

Two two-dimensional (2D) donor–acceptor (D-A) type conjugated polymers (CPs), namely, PBDT-TVT-BT and PBDT-TVT-FBT, in which two ((E)-(4,5-didecylthien-2-yl)vinyl)- 5-thien-2-yl (TVT) side chains were introduced into 4,8-position of benzo[1,2-b:4,5-bʹ]dithiophene (BDT) to synthesize the highly conjugated electron-donating building block BDT-TVT, and benzothiadiazole (BT) and/or 5,6-difluoro-BT as electron-accepting unit, were designed to systematically ascertain the impact of fluorination on thermal stability, optoelectronic property, and photovoltaic performance. Both resultant copolymers exhibited the lower bandgap (1.60 ~ 1.69 eV) and deeper highest occupied molecular orbital energy level (EHOMO, –5.17 ~ –5.37 eV). It was found that the narrowed absorption, deepened EHOMO and weakened aggregation in solid film but had insignificant influence on thermal stability after fluorination in PBDT-TVT-FBT. Accordingly, a PBDT-TVT-FBT-based device yielded 16% increased power conversion efficiency (PCE) from 4.50% to 5.22%, benefited from synergistically elevated VOC, JSC, and FF, which was mainly originated from deepened EHOMO, increased μh, μe, and more balanced μh/μe ratio, higher exciton dissociation probability and improved microstructural morphology of the photoactive layer as a result of incorporating fluorine into the polymer backbone.

Synergistic effects of an alkylthieno[3,2-b]thiophene π-bridging backbone extension on the photovoltaic performances of donor–acceptor copolymers

2017 ◽  
Vol 5 (21) ◽  
pp. 10269-10279 ◽  
Author(s):  
Hyeongjin Hwang ◽  
Dong Hun Sin ◽  
Chandramouli Kulshreshtha ◽  
Byungho Moon ◽  
Jiwon Son ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Photovoltaic Properties ◽  
Donor Acceptor ◽  
Conjugated Copolymers

Synergistic effects of a thiophene-based π-bridging backbone extension on the photovoltaic properties of the conjugated copolymers were systematically studied.

Isoindigo fluorination to enhance photovoltaic performance of donor–acceptor conjugated copolymers

2014 ◽  
Vol 50 (4) ◽  
pp. 439-441 ◽  
Author(s):  
Yuchong Yang ◽  
Renming Wu ◽  
Xin Wang ◽  
Xiaopeng Xu ◽  
Zuojia Li ◽  
...  
Keyword(s):  
Photovoltaic Performance ◽  
Donor Acceptor ◽  
Conjugated Copolymers

scholarly journals Elevated Photovoltaic Performance in Medium Bandgap Copolymers Composed of Indacenodi-thieno[3,2-b]thiophene and Benzothiadiazole Subunits by Modulating the π-Bridge

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 368 ◽  
Author(s):  
Lili An ◽  
Junfeng Tong ◽  
Yubo Huang ◽  
Zezhou Liang ◽  
Jianfeng Li ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Photovoltaic Performance ◽  
Molecular Geometry ◽  
Orbital Energy ◽  
Polymer Backbone ◽  
Photoactive Layer ◽  
Enhanced Absorption ◽  
Highest Occupied Molecular Orbital ◽  
The Impact ◽  
Orbital Energy Level

Two random conjugated polymers (CPs), namely, PIDTT-TBT and PIDTT-TFBT, in which indacenodithieno[3,2-b]thiophene (IDTT), 3-octylthiophene, and benzothiadiazole (BT) were in turn utilized as electron-donor (D), π-bridge, and electron-acceptor (A) units, were synthesized to comprehensively analyze the impact of reducing thiophene π-bridge and further fluorination on photostability and photovoltaic performance. Meanwhile, the control polymer PIDTT-DTBT with alternating structure was also prepared for comparison. The broadened and enhanced absorption, down-shifted highest occupied molecular orbital energy level (EHOMO), more planar molecular geometry thus enhanced the aggregation in the film state, but insignificant impact on aggregation in solution and photostability were found after both reducing thiophene π-bridge in PIDTT-TBT and further fluorination in PIDTT-TFBT. Consequently, PIDTT-TBT-based device showed 185% increased PCE of 5.84% profited by synergistically elevated VOC, JSC, and FF than those of its counterpart PIDTT-DTBT, and this improvement was chiefly ascribed to the improved absorption, deepened EHOMO, raised μh and more balanced μh/μe, and optimized morphology of photoactive layer. However, the dropped PCE was observed after further fluorination in PIDTT-TFBT, which was mainly restricted by undesired morphology for photoactive layer as a result of strong aggregation even if in the condition of the upshifted VOC. Our preliminary results can demonstrate that modulating the π-bridge in polymer backbone was an effective method with the aim to enhance the performance for solar cell.

scholarly journals Push-Pull Heterocyclic Dyes Based on Pyrrole and Thiophene: Synthesis and Evaluation of Their Optical, Redox and Photovoltaic Properties

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Sara S. M. Fernandes ◽  
Maria Cidália R. Castro ◽  
Dzmitry Ivanou ◽  
Adélio Mendes ◽  
Maria Manuela M. Raposo
Keyword(s):  
Electron Donor ◽  
Oxidation Potential ◽  
Cyanoacetic Acid ◽  
Strong Electron ◽  
Photovoltaic Properties ◽  
Heterocyclic Molecules ◽  
Acceptor Group ◽  
Donor Acceptor ◽  
Ethoxyl Group ◽  
Anchoring Groups

Three heterocyclic dyes were synthesized having in mind the changes in the photovoltaic, optical and redox properties by functionalization of 5-aryl-thieno[3,2-b]thiophene, 5-arylthiophene and bis-methylpyrrolylthiophene π-bridges with different donor, acceptor/anchoring groups. Knoevenagel condensation of the aldehyde precursors with 2-cyanoacetic acid was used to prepare the donor-acceptor functionalized heterocyclic molecules. These organic metal-free dyes are constituted by thieno[3,2-b]thiophene, arylthiophene, bis-methylpyrrolylthiophene, spacers and one or two cyanoacetic acid acceptor groups and different electron donor groups (alkoxyl, and pyrrole electron-rich heterocycle). The evaluation of the redox, optical and photovoltaic properties of these compounds indicate that 5-aryl-thieno[3,2-b]thiophene-based dye functionalized with an ethoxyl electron donor and a cyanoacetic acid electron acceptor group/anchoring moiety displays as sensitizer for DSSCs the best conversion efficiency (2.21%). It is mainly assigned to the higher molar extinction coefficient, long π-conjugation of the heterocyclic system, higher oxidation potential and strong electron donating capacity of the ethoxyl group compared to the pirrolyl moiety.

scholarly journals Effect of Electron-Withdrawing Fluorine and Cyano Substituents on Photovoltaic Properties of Two-Dimensional Quinoxaline-Based Polymers

2021 ◽  
Author(s):  
Seok Woo Lee ◽  
MD Waseem Hussain ◽  
Sanchari Shome ◽  
Su Ryong Ha ◽  
Jae Taek Oh ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transport ◽  
Electrochemical Properties ◽  
Polymer Solar Cells ◽  
Power Conversion ◽  
Photovoltaic Performance ◽  
Two Dimensional ◽  
Strong Electron ◽  
Photovoltaic Properties ◽  
Kinetics Of

Abstract In this study, strong electron-withdrawing fluorine (F) and cyano (CN) substituents are selectively incorporated into the quinoxaline unit of two-dimensional (2D) D–A-type polymers to investigate their effects on the photovoltaic properties of the polymers. To construct the 2D polymeric structure, electron-donating benzodithiophene and methoxy-substituted triphenylamine are directly linked to the horizontal and vertical directions of the quinoxaline acceptor, respectively. After analyzing the structural, optical, and electrochemical properties of the resultant F- and CN-substituted polymers, labeled as PBCl-MTQF and PBCl-MTQCN, respectively, inverted-type polymer solar cells with a non-fullerene Y6 acceptor are fabricated to investigate the photovoltaic performances of the polymers. It is discovered that the maximum power conversion efficiency of PBCl-MTQF is 7.48%, whereas that of PBCl-MTQCN is limited to 3.10%. This significantly reduced PCE of the device based on PBCl-MTQCN is ascribed to the formation of irregular, large aggregates in the active layer, which can readily aggravate the charge recombination and charge transport kinetics of the device. Therefore, the photovoltaic performance of 2D quinoxaline-based D–A-type polymers is significantly affected by the type of electron-withdrawing substituent.

scholarly journals Effect of electron-withdrawing fluorine and cyano substituents on photovoltaic properties of two-dimensional quinoxaline-based polymers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seok Woo Lee ◽  
MD. Waseem Hussain ◽  
Sanchari Shome ◽  
Su Ryong Ha ◽  
Jae Taek Oh ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transport ◽  
Electrochemical Properties ◽  
Polymer Solar Cells ◽  
Power Conversion ◽  
Photovoltaic Performance ◽  
Two Dimensional ◽  
Strong Electron ◽  
Photovoltaic Properties ◽  
Kinetics Of

AbstractIn this study, strong electron-withdrawing fluorine (F) and cyano (CN) substituents are selectively incorporated into the quinoxaline unit of two-dimensional (2D) D–A-type polymers to investigate their effects on the photovoltaic properties of the polymers. To construct the 2D polymeric structure, electron-donating benzodithiophene and methoxy-substituted triphenylamine are directly linked to the horizontal and vertical directions of the quinoxaline acceptor, respectively. After analyzing the structural, optical, and electrochemical properties of the resultant F- and CN-substituted polymers, labeled as PBCl-MTQF and PBCl-MTQCN, respectively, inverted-type polymer solar cells with a non-fullerene Y6 acceptor are fabricated to investigate the photovoltaic performances of the polymers. It is discovered that the maximum power conversion efficiency of PBCl-MTQF is 7.48%, whereas that of PBCl-MTQCN is limited to 3.52%. This significantly reduced PCE of the device based on PBCl-MTQCN is ascribed to the formation of irregular, large aggregates in the active layer, which can readily aggravate the charge recombination and charge transport kinetics of the device. Therefore, the photovoltaic performance of 2D quinoxaline-based D–A-type polymers is significantly affected by the type of electron-withdrawing substituent.

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