Different Effect of the Additional Electron-Withdrawing Cyano Group in Different Conjugation Bridge: The Adjusted Molecular Energy Levels and Largely Improved Photovoltaic Performance

2016 ◽  
Vol 8 (19) ◽  
pp. 12134-12140 ◽  
Author(s):  
Huiyang Li ◽  
Manman Fang ◽  
Yingqin Hou ◽  
Runli Tang ◽  
Yizhou Yang ◽  
...  
Keyword(s):  
Cyano Group ◽  
Energy Levels ◽  
Photovoltaic Performance

scholarly journals Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

2017 ◽  
Vol 13 ◽  
pp. 863-873 ◽  
Author(s):  
Vinila N Viswanathan ◽  
Arun D Rao ◽  
Upendra K Pandey ◽  
Arul Varman Kesavan ◽  
Praveen C Ramamurthy
Keyword(s):  
Molecular Orbital ◽  
Architectural Design ◽  
Density Functional ◽  
Short Circuit ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Hole Mobility ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Lowest Unoccupied Molecular Orbital

A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at −5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2, were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3.

scholarly journals Polymerized small molecular acceptor based all-polymer solar cells with an efficiency of 16.16% via tuning polymer blend morphology by molecular design

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaqi Du ◽  
Ke Hu ◽  
Jinyuan Zhang ◽  
Lei Meng ◽  
Jiling Yue ◽  
...  
Keyword(s):  
Solar Cells ◽  
Molecular Design ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Electronic Energy ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Electronic Energy Levels ◽  
20 Nm

AbstractAll-polymer solar cells (all-PSCs) based on polymerized small molecular acceptors (PSMAs) have made significant progress recently. Here, we synthesize two A-DA’D-A small molecule acceptor based PSMAs of PS-Se with benzo[c][1,2,5]thiadiazole A’-core and PN-Se with benzotriazole A’-core, for the studies of the effect of molecular structure on the photovoltaic performance of the PSMAs. The two PSMAs possess broad absorption with PN-Se showing more red-shifted absorption than PS-Se and suitable electronic energy levels for the application as polymer acceptors in the all-PSCs with PBDB-T as polymer donor. Cryogenic transmission electron microscopy visualizes the aggregation behavior of the PBDB-T donor and the PSMA in their solutions. In addition, a bicontinuous-interpenetrating network in the PBDB-T:PN-Se blend film with aggregation size of 10~20 nm is clearly observed by the photoinduced force microscopy. The desirable morphology of the PBDB-T:PN-Se active layer leads its all-PSC showing higher power conversion efficiency of 16.16%.

Rhodaninedyes for dye-sensitized solar cells :  spectroscopy, energy levels and photovoltaic performance

2009 ◽  
Vol 11 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Tannia Marinado ◽  
Daniel P. Hagberg ◽  
Maria Hedlund ◽  
Tomas Edvinsson ◽  
Erik M. J. Johansson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Dye Sensitized Solar Cells ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

The impact of heteroatom substitution on cross-conjugation and its effect on the photovoltaic performance of DSSCs – a computational investigation of linear vs. cross-conjugated anchoring units

2018 ◽  
Vol 20 (35) ◽  
pp. 22660-22673 ◽  
Author(s):  
Mahalingavelar Paramasivam ◽  
Ramesh Kumar Chitumalla ◽  
Joonkyung Jang ◽  
Ji Ho Youk
Keyword(s):  
Photophysical Properties ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Computational Investigation ◽  
Conjugated Systems ◽  
Reverse Trend ◽  
Heteroatom Substitution ◽  
The Impact

The heteroatom substitution on cross conjugation takes a reverse trend to the linear π-conjugated systems by means of energy levels and photophysical properties. The resultant changes directly affecting the photovoltaic performance of DSSCs.

Copolymerization of 3,3′′′-didodecylquaterthiophene with fluorene and silole units: improving photovoltaic performance by tuning energy levels

2012 ◽  
Vol 3 (10) ◽  
pp. 2794 ◽  
Author(s):  
Hongyu Wang ◽  
Jun Gao ◽  
Weiqi Tong ◽  
Qun Qian ◽  
Kunhua Lin ◽  
...  
Keyword(s):  
Energy Levels ◽  
Photovoltaic Performance

scholarly journals Effect of the π-conjugation length on the properties and photovoltaic performance of A–π–D–π–A type oligothiophenes with a 4,8-bis(thienyl)benzo[1,2-b:4,5-b′]dithiophene core

2016 ◽  
Vol 12 ◽  
pp. 1788-1797 ◽  
Author(s):  
Ni Yin ◽  
Lilei Wang ◽  
Yi Lin ◽  
Jinduo Yi ◽  
Lingpeng Yan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Organic Solar Cells ◽  
Energy Levels ◽  
Power Conversion ◽  
Photovoltaic Performance ◽  
Terminal Group ◽  
Absorption Bands ◽  
Conjugated Molecules

Benzo[1,2-b:4,5-b′]dithiophene (BDT) is an excellent building block for constructing π-conjugated molecules for the use in organic solar cells. In this paper, four 4,8-bis(5-alkyl-2-thienyl)benzo[1,2-b:4,5-b′]dithiophene (TBDT)-containing A–π–D–π–A-type small molecules (COOP-nHT-TBDT, n = 1, 2, 3, 4), having 2-cyano-3-octyloxy-3-oxo-1-propenyl (COOP) as terminal group and regioregular oligo(3-hexylthiophene) (nHT) as the π-conjugated bridge unit were synthesized. The optical and electrochemical properties of these compounds were systematically investigated. All these four compounds displayed broad absorption bands over 350–600 nm. The optical band gap becomes narrower (from 1.94 to 1.82 eV) and the HOMO energy levels increased (from −5.68 to −5.34 eV) with the increase of the length of the π-conjugated bridge. Organic solar cells using the synthesized compounds as the electron donor and PC61BM as the electron acceptor were fabricated and tested. Results showed that compounds with longer oligothiophene π-bridges have better power conversion efficiency and higher device stability. The device based on the quaterthiophene-bridged compound 4 gave a highest power conversion efficiency of 5.62% with a V OC of 0.93 V, J SC of 9.60 mA·cm−2, and a FF of 0.63.

DFT investigation on organic dyes with cross-conjugated cyano groups

2014 ◽  
Vol 13 (01) ◽  
pp. 1450008
Author(s):  
Chunhe Yang ◽  
Aiwei Tang ◽  
Fujun Zhang ◽  
Feng Teng
Keyword(s):  
Density Functional ◽  
Molecular Conformation ◽  
Organic Dyes ◽  
Cyano Group ◽  
Energy Levels ◽  
Orbital Energy ◽  
Dye Molecules ◽  
Conjugated Molecules ◽  
Functional Theory ◽  
Cyano Groups

Organic dye molecules with the acceptor moieties, cyano groups, cross-conjugated to the donor moieties, have been investigated theoretically. Density functional theory (DFT) calculations on such cross-conjugated molecules reveal the effects of cross-conjugation on the geometric and electronic structures of the molecules. The cross-conjugated cyano groups in the dye molecules are found effective to alter the charge population and the frontier orbital energy levels of the dyes. The effects of cross-conjugation of cyano group on the molecular conformation, the charge transfer, and polarity of the dyes are discussed.

Indacenodithiophene: a promising building block for high performance polymer solar cells

2017 ◽  
Vol 5 (22) ◽  
pp. 10798-10814 ◽  
Author(s):  
Yongxi Li ◽  
Minchao Gu ◽  
Zhe Pan ◽  
Bin Zhang ◽  
Xutong Yang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Building Block ◽  
High Performance ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Conjugated Materials ◽  
Factors Affecting ◽  
High Performance Polymer ◽  
Photovoltaic Applications

This review surveys recent research advances in the area of IDT-based conjugated materials for photovoltaic applications. The factors affecting the bandgaps, molecular energy levels, film morphologies, as well as the photovoltaic performance of these materials have also been discussed.

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.

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