A rational comparison of the effects of halogen atoms incorporated into the polymer donors on the performance of polymer solar cells

Huang, Shaorong; Huang, Xuexiang; Chen, Lie; Liao, Zhihui; Ding, Shanshan; Yuan, Zhongyi; Chen, Yiwang

doi:10.1016/j.orgel.2019.04.011

Cited by 14 publications

(11 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A direct comparison of the effects of F and Cl incorporation was carried out by Huang et al by synthesizing D–A copolymers based on alternate carboxylate‐substituted polythiophene acceptors and 2F‐BDT (PBDT‐F‐3T2C) or 2Cl‐BDT (PBDT‐Cl‐3T2C, P18 ) donor (Scheme ) . P18 demonstrated a low‐lying frontier energy level due to the empty 3d orbitals of the Cl atom, whereas PBDT‐F‐3T2C exhibited higher crystallinity, attributed to stronger intermolecular interactions of the F atoms.…”

Section: Chlorine Substitution On Donor Unitsmentioning

confidence: 99%

Design Principles and Synergistic Effects of Chlorination on a Conjugated Backbone for Efficient Organic Photovoltaics: A Critical Review

2020

View full text Add to dashboard Cite

The pursuit of low‐cost, flexible, and lightweight renewable power resources has led to outstanding advancements in organic solar cells (OSCs). Among the successful design principles developed for synthesizing efficient conjugated electron donor (ED) or acceptor (EA) units for OSCs, chlorination has recently emerged as a reliable approach, despite being neglected over the years. In fact, several recent studies have indicated that chlorination is more potent for large‐scale production than the highly studied fluorination in several aspects, such as easy and low‐cost synthesis of materials, lowering energy levels, easy tuning of molecular orientation, and morphology, thus realizing impressive power conversion efficiencies in OSCs up to 17%. Herein, an up‐to‐date summary of the current progress in photovoltaic results realized by incorporating a chlorinated ED or EA into OSCs is presented to recognize the benefits and drawbacks of this interesting substituent in photoactive materials. Furthermore, other aspects of chlorinated materials for application in all‐small‐molecule, semitransparent, tandem, ternary, single‐component, and indoor OSCs are also presented. Consequently, a concise outlook is provided for future design and development of chlorinated ED or EA units, which will facilitate utilization of this approach to achieve the goal of low‐cost and large‐area OSCs.

show abstract

Section: Chlorine Substitution On Donor Unitsmentioning

confidence: 99%

Design Principles and Synergistic Effects of Chlorination on a Conjugated Backbone for Efficient Organic Photovoltaics: A Critical Review

2020

View full text Add to dashboard Cite

show abstract

“…Finally, the PSC base on PBDT-F-3T2C:IT-4F obtained a PCE of 11.67 and 10.04% processed by chlorobenzene (CB) and 1,2,4-trimethylbenzene solvent, respectively, both of which were higher than those based on PBDT-Cl-3T2C:IT-4F (10.19 and 5.83%). 37 The above results suggest that the substituent groups both on the conjugated thiophene side chains of BDT and ester of TTC units have great effect on the molecular aggregation, optoelectronic properties, and device performance.…”

Section: Introductionmentioning

confidence: 85%

“…Recently, Chen et al also prepared two BDT-TTC -based D–A polymers PBDT-F-3T2C and PBDT-Cl-3T2C containing the fluorinated and chlorinated alkylthiophene side chains, respectively, to investigate halogenation effects on optoelectronic properties and device performance. Finally, the PSC base on PBDT-F-3T2C:IT-4F obtained a PCE of 11.67 and 10.04% processed by chlorobenzene (CB) and 1,2,4-trimethylbenzene solvent, respectively, both of which were higher than those based on PBDT-Cl-3T2C:IT-4F (10.19 and 5.83%) . The above results suggest that the substituent groups both on the conjugated thiophene side chains of BDT and ester of TTC units have great effect on the molecular aggregation, optoelectronic properties, and device performance.…”

Section: Introductionmentioning

confidence: 87%

“…Benzo[1,2- b :4,5- b ′]dithiophene ( BDT ) is well demonstrated to be an outstanding donor (D) unit combining with suitable acceptor (A) units to construct efficient donor–acceptor (D–A) alternating copolymers due to its natural merits of moderate electron-donating ability, fine planarity, tunable chemical structure, and so forth. − Many wide-band gap D–A copolymers have been developed by copolymerizing BDT with a middle electron-withdrawing strength A moieties, such as benzodithiophene-4,8-dione (BDD), − fluorobenzotriazoles (FBTAs), − and ester-modified (oligo)thiophene. − Among them, D–A copolymers based on thiophene-substituted BDT and ester-modified terthiophene, for example, 2,2′:5′,2″-terthiophene-3,3″-dicarboxylate ( TTC ), have received considerable attention because these BDT-TTC -based polymers exhibited large E g opt (>1.9 eV), deep-lying highest occupied molecular orbital (HOMO) levels (∼−5.4 eV), and high charge mobilities, thus resulting in excellent device performance paired with low-band gap SMAs. − Most research studies have focused on tuning and optimizing the molecular structure, optoelectronic properties, aggregation behavior, film morphology, and device performance by modifying the conjugated side chains of the BDT unit and/or nonconjugated side of the ester group in the TTC unit. Hou’s group first designed and synthesized a D–A wide-band gap BDT-TTC -based polymer PB3T with alkylthiothiophene-substituted BDT and 2-ethylhexyl-modified TTC as the D and A units, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synergetic Effect of Side-Chain Engineering of Polymer Donors and Conformation Tuning of Small-Molecule Acceptors on Molecular Properties, Morphology, and Photovoltaic Performance

Zeng

Tang

et al. 2021

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

It is demonstrated that the side-chain engineering of polymer donors and molecular conformation of small-molecule acceptors (SMAs) plays a crucial role in the morphology and photovoltaic performance of polymer solar cells (PSCs). However, the synergetic effect of these two aspects has been rarely reported. Herein, two wide-band gap donor−acceptor (D−A) copolymers (PST-TTC and PSPT-TTC) featuring the same main-chain backbone but different conjugated side chains were developed and combined with three low-band gap symmetric SMAs (ITIC, DTCFO-ICCl, and Y6) with various molecular conformations (Sshape, C-shape, and U-shape) to investigate the synergetic effect of side-chain engineering of polymer donors and conformation manipulation of SMAs on molecular properties, device physics, film morphology, and photovoltaic performance. The results indicate that PST-TTC with an alkylthiothiophene side chain exhibits a broader absorption spectrum, a smaller optical band gap (1.95 vs 1.99 eV), and a deeper-lying highest occupied molecular orbital (HOMO) level (−5.39 vs −5.36 eV) as compared to PSPT-TTC with an alkylthiophenylthiophene side chain. The PSCs were constructed according to the different donor/acceptor combinations based on the two as-synthesized polymers and three selected SMAs. After optimization, PST-TTC paired with Sshaped ITIC provides a power conversion efficiency (PCE) of 10.10% and the PCE can be further improved up to 10.60% when Cshaped DTCFO-ICCl was used to replace ITIC as the acceptor. However, the device performance becomes worse, accompanied with a sharply reduced PCE of 7.36% after the substitution of ITIC for U-shaped Y6. On the contrary, when the paired donor was changed to PSPT-TTC, the PSPT-TTC:Y6-based PSC achieves a remarkably increased PCE of up to 11.46%. These delicate observations suggest that the polymer donor with different conjugated side chains should collaborate with symmetric SMAs possessing various molecular conformations to realize superior morphology and device performance.

show abstract

“…Meanwhile, a more flat planar molecular structure adopted by l-IDTBTRh compared with the a-IDTBTRh segment may facilitate the charge transport, as verified by density-functional theory (DFT) calculation provided in Figure S8, Supporting Information. [34][35][36] l-IDTBTRh shows a nearly flat planar backbone with dihedral angle of 1.97 , while a-IDTBTRh adopts a slightly more twisted conformation (about 10.49 ).…”

Section: Photobleaching Rates In Solutions and In As-cast Filmsmentioning

confidence: 99%

Photooxidation Analysis of Two Isomeric Nonfullerene Acceptors: A Systematic Study of Conformational, Morphological, and Environmental Factors

Guo

Sun

et al. 2021

Solar RRL

View full text Add to dashboard Cite

Despite the striking progress toward improving the efficiencies of organic solar cells (OSCs) resulting from the development of nonfullerene acceptors (NFAs), there is a rising requirement of investigation of the molecular design for achieving photochemically stable NFAs. Herein, applying two isomeric NFA molecules a‐IDTBTRh and l‐IDTBTRh based on angular‐indaceno[2,1‐b:6,5‐b′]dithiophene (a‐IDT) and linear‐IDT (l‐IDT) as the central cores, the effects of molecular conformation, aggregation behavior, and environmental factors on their photooxidation degradation processes are systematically studied. It is found that tuning regioisomeric central cores on the molecular skeleton influences the backbone conformation and conjugation, resulting in the different optoelectronic properties and molecular stacking characteristics. A strong molecular aggregation dependence of the optical losses and degradation mechanics in the annealed neat films is also observed, and it is shown that l‐IDTBTRh is much more photostable than its less‐ordered core derivative, a‐IDTBTRh. Furthermore, the effects of external environmental stresses on photobleaching behaviors of the annealed thin films are studied systematically, highlighting the role of concentrated light in accelerating photooxidation of organic materials. The results not only provide a comprehensive insight into the photooxidation properties and attenuation mechanisms of organic materials, but also suggest guidelines to rationally select materials for stable OSCs.

show abstract

A rational comparison of the effects of halogen atoms incorporated into the polymer donors on the performance of polymer solar cells

Cited by 14 publications

References 31 publications

Design Principles and Synergistic Effects of Chlorination on a Conjugated Backbone for Efficient Organic Photovoltaics: A Critical Review

Design Principles and Synergistic Effects of Chlorination on a Conjugated Backbone for Efficient Organic Photovoltaics: A Critical Review

Synergetic Effect of Side-Chain Engineering of Polymer Donors and Conformation Tuning of Small-Molecule Acceptors on Molecular Properties, Morphology, and Photovoltaic Performance

Photooxidation Analysis of Two Isomeric Nonfullerene Acceptors: A Systematic Study of Conformational, Morphological, and Environmental Factors

Contact Info

Product

Resources

About