Synthesis of a new W-type of functional polymer for improving intermolecular charge transfer processes at donor/acceptor interfaces

Abstract

Optimizing charge transfer (CT) processes at donor/acceptor interfaces is an important subject to improving photocurrent density. Geometries of functional polymers play important roles in design of new types of polymers, which were used as electron donor to improve effective separation of electron-hole pairs at donor/acceptor interfaces. In this article, a novel W-type of polymer, poly(1-[4-(9-(2-ethylhexyl)carbazole-3-yl)]phenylazo-2-phenylazoacenaphthylene), was synthesized by a Suzuki coupling reaction for improving interaction between polymers and electron acceptors to enhance intermolecular CT. Geometry of combination of the polymer and C₆₀ shows that main-chain of the polymer could sufficiently touch C₆₀ derivatives. The polymer exhibited a broadband light absorption at the wavelength range from 250 to 650 nm. Ultraviolet–visible spectra and cyclic voltammetry curve suggest that the highest occupied, lowest unoccupied molecular orbital energy levels, and energy gap values are −5.09, −3.18 and 1.91 eV. Fluorescence quenching experiments shows that 99.9% of emission fluorescence of the polymer was quenched by added C₆₀. Therefore, excited electrons at the polymer would be completely transferred to C₆₀ molecules. This article suggests a new W-type functional polymer for improving intermolecular CT processes at donor/acceptor interfaces.

Keywords

W-type polymer charge transfer geometry electron-hole pair fluorescence quenching

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References

Geng

Duan

. Theoretical study on the charge transfer mechanism at donor/acceptor interface: Why TTF/TCNQ is inadaptable to photovoltaics? J Chem Phys 2016; 145(24): 244705(1–9).

R. Fitzner

Mena-Osteritz

Walzer

. A–D–A-type oligothiophenes for small molecule organic solar cells: extending the π-system by introduction of ring-locked double bonds. Adv Funct Mater 2015; 25(12): 1845–1856.

Xia

Zhu

Zhao

. Effect on absorption and electron transfer by using Cd(II) or Cu(II) complexes with phenanthroline as auxiliary electron acceptors (A) in D-A-π-A motif sensitizers for dye-sensitized solar cells. Phys Chem Chem Phys 2018; 20(9): 6688–6697.

Chang

Chen

Yang

. Novel perylene diimide based polymeric electron-acceptors containing ethynyl as the π-bridge for all-polymer solar cells. Org Electron 2017; 45: 227–233.

Shen

Zhou

Zhao

. Photoinduced electron transfer in conjugated molecules containing different donor in an external electric field. Spectrochim Acta A 2019; 208: 294–298.

Stoltzfus

Larson

Zarrabi

. Investigating charge generation in polymer: non-fullerene acceptor bulk heterojunction films. Org Electron 2018; 55: 177–186.

Armin

Kassal

Shaw

. Spectral dependence of the internal quantum efficiency of organic solar cells: effect of charge generation pathways. J Am Chem Soc 2014; 136: 11465–11472.

Zhou

Chen

. Improving the photovoltaic performance of polymer solar cells based on furan-flanked diketopyrrolopyrrole copolymers via tuning the alkyl side chain. J Phys Chem C 2016; 120: 4824–4832.

Hellemans

Gebel

Herman

. Spotlights on recent JACS pubblications. J Am Chem Soc 2013; 135: 1165–1166.

10.

Cheng

Yang

Hsu

. Synthesis of conjugated polymers for organic solar cell applications. Chem Rev 2009; 109: 5868–5923.

11.

Zhang

Pei

. Theoretical investigations on donor-acceptor conjugated copolymers based on naphtho [1,2-c:5,6-c] bis [1,2,5] thiadiazole for organic solar cell applications. J Phys Chem C 2012; 116: 26154–26161.

12.

Meng

Wang

. A cross-linkable donor polymer as the underlying layer to tune the active layer morphology of polymer solar cells. Adv Funct Mater 2016; 26: 226–232.

13.

Yao

Zhao

Zheng

. PBDT-TSR: a highly efficient conjugated polymer for polymer solar cells with a regioregular structure. J Mater Chem A 2016; 4: 1708–1713.

14.

Zhu

Yang

Muntwiler

. Charge-transfer excitons at organic semiconductor surfaces and interfaces. Acc Chem Res 2009; 42: 1779–1787.

15.

Zhao

Liang

. Charge transfer in organic molecules for solar cells: theoretical perspective. Chem Soc Rev 2012; 41: 1075–1087.

16.

Liang

Lin

Lai

. Synthesis, characterization, and photovoltaic applications of donor-acceptor alternating and random copolymers based on a ladder-type nonacyclic structure. React. Funct. Polym 2016; 108: 113–121.

17.

Song

Choi

. Significance of polymeric nanowire-network structures for stable and efficient organic solar cells. Macromol Res 2018; 26(7): 623–629.

18.

Mayer

Toney

Scully

. Bimolecular crystals of fullerenes in conjugated polymers and the implications of molecular mixing for solar cell. Adv Funct Mater 2009; 19: 1173–1179.

19.

Friedel

McNeill

Greenham

. Influence of alkyl side-chain length on the performance of poly(3-alkylthiophene)/polyfluorene all-polymer solar cells. Chem Mater 2010; 22: 3389–3398.

20.

Zheng

Zhuang

Qiu

. Antiaromatic characteristic analysis of 1,4-diazapentalene derivatives: a theoretical study. J Phys Chem A 2015; 119: 3762–3769.

21.

Ding

Song

. Development of a new s-tetrazine-based copolymer for efficient solar cells. J Am Chem Soc 2010; 132: 13160–13161.

22.

Zhang

Shen

Yuan

. Syntheses and optoelectronic properties of planar compounds 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine. J Heterocyclic Chem 2016; 53(6): 1813–1819.

23.

Frisch

Trucks

Schlegel

. Gaussian 03, Revision B.04. Pittsburgh: Gaussian, 2003.

24.

Becke

AD.

Density-functional thermochemistry. III. The role of exact exchange. J Chem Phys 1993; 98: 5648–5652.

25.

Zhang

Shen

. Synthesis of an A-D-A type of molecule used as electron acceptor for improving charge transfer in organic solar cells. Chem Phys 2016; 475: 104–111.

26.

Zhang

Yuan

. Effect of bromine substituent on optical properties of compounds. J Phys Org Chem 2017; 30: e3620.

27.

Xue

. Energy level and molecular structure engineering of conjugated donor-acceptor copolymers for photovoltaic applications. Macromolecules 2009; 42: 4491–4499.

28.

Sahoo

Sugiyasu

Tian

. Effect of conjugated backbone protection on intrinsic and light-induced fluorescence quenching in polythiophenes. Chem Mater 2014; 26: 4867–4875.

29.

Lee

Choi

Ahn

. Ternary blend composed of two organic donors and one acceptor for active layer of high-performance organic solar cells. ACS Appl Mater Interfaces 2016; 8: 10961–10967.

30.

Sun

. Fluorescence spectra and quantum yields of C₆₀ and C₇₀ under different solvent conditions. A quantitative examination using a near-infrared-sensitive emission spectrometer. J Chem Soc Perkin Trans 1996; 2: 2157–2162.

31.

Zhao

Fang

. Fluorescence of C₆₀ and its interaction with pyridine. J Phys Chem 2004; 108: 13586–13588.