Synthesis and Thermoelectric Properties of Dithieno[3,2-b:2′,3′-d]pyrrole-Based D-A Conjugated Polymers

doi:10.12422/j.issn.1006-396X.2024.03.001

Abstract

Abstract:

To investigate the effect of donor unit length on the thermoelectric properties of D-A conjugated polymer,three D-A conjugated polymers(PDPP-DTP,PDPP-2DTP,PDPP-3DTP) based on dithieno[3,2-b:2′,3′-d]pyrrole (DTP) with different donor unit lengths were designed and synthesized.The influence of donor unit lengths on the energy levels of the polymers was studied by electrochemical characterization and density functional theory calculations.With ferric chloride as dopant,the polymer films were oxidation doped.Their optical and thermoelectric properties as well as the temperature dependent resistance were discussed.The results show that the HOMO energy levels of the polymers gradually increase with the extension of the length of the DTP-like donor unit,which makes them easier to be oxidatively doped.At the same dopant concentration,the doped polymers exhibit higher conductivity with the extension of the donor unit length.Among them,PDPP-3DTP shows the highest electrical conductivity of 302.3 S/cm,which is much higher than that of PDPP-2DTP(106.2 S/cm) and PDPP-DTP(64.7 S/cm).The charge transport energy barrier of the polymer films gradually decreases with the extension of the length of the donor unit,which is beneficial for the enhancement of electrical conductivity of doped films.However,the Seebeck coefficient of the doped polymer film decreases with the extension of the length of the donor unit,and the final polymer PDPP-2DTP is doped and optimized to have the highest thermoelectric power factor of 19.4 μW/(m·K²).

Key words: D-A conjugated polymers, Thermoelectric, Dithieno[3,2-b:2′,3′-d]pyrrole, Donor unit length, Doping

摘要：

为探究D-A共轭聚合物中给体单元长度对其热电性能的影响，设计合成了3种含不同给体单元长度的二噻吩并吡咯（DTP）类的D-A共轭聚合物（PDPP-DTP、PDPP-2DTP、PDPP-3DTP），通过电化学表征结合密度泛函理论计算的方法研究了给体单元长度对聚合物能级的影响，并以三氯化铁作为掺杂剂对聚合物薄膜进行氧化掺杂，研究了其光学性质、热电性能及电阻随温度变化的规律。结果表明，随着DTP类给体单元长度的延长，聚合物的HOMO能级逐渐升高，使其更容易氧化掺杂；在相同的掺杂剂浓度下，掺杂后聚合物的电导率随着给体单元长度的延长而升高；PDPP-3DTP的最高电导率达到302.3 S/cm，远高于PDPP-2DTP（106.2 S/cm）和PDPP-DTP（64.7 S/cm）；随着给体单元长度的延长，聚合物薄膜的电荷传输能垒逐渐降低，有利于提高掺杂薄膜的电导率；随着给体单元长度的延长，掺杂后聚合物薄膜的塞贝克系数降低；聚合物PDPP-2DTP经掺杂优化后，其热电功率因子最高，其值达到19.4 μW/(m?K²)。

关键词: D-A共轭聚合物, 热电, 二噻吩并吡咯, 给体单元长度, 掺杂

CLC Number:

TQ317.5

Ting LIN, Yuhang ZHANG, Hui LI, Pengcheng LI. Synthesis and Thermoelectric Properties of Dithieno[3,2-b:2′,3′-d]pyrrole-Based D-A Conjugated Polymers[J]. Journal of Petrochemical Universities, 2024, 37(3): 1-10.

林婷, 张宇航, 李慧, 李鹏程. 基于二噻吩并吡咯的D-A共轭聚合物的合成及热电性能研究[J]. 石油化工高等学校学报, 2024, 37(3): 1-10.

Figures/Tables 8

Fig.1 Molecular structure and synthesis route of intermediates and polymers

Table 1 Molecular weight and PDI of the polymers

聚合物	M_n/kDa	PDI
PDPP-DTP	13.9	3.0
PDPP-2DTP	20.2	1.4
PDPP-3DTP	7.2	1.5

Fig.2 Cyclic voltammograms of the polymers

Table 2 Electrochemical properties parameters of the polymers

聚合物	$E H O M O c v$ /eV	$E L U M O c v$ /eV	E $g c v$ /eV
PDPP-DTP	-4.84	-3.34	1.53
PDPP-2DTP	-4.75	-3.32	1.23
PDPP-3DTP	-4.47	-3.31	1.13

Table 2 Electrochemical properties parameters of the polymers

聚合物	$E H O M O c v$ /eV	$E L U M O c v$ /eV	E $g c v$ /eV
PDPP-DTP	-4.84	-3.34	1.53
PDPP-2DTP	-4.75	-3.32	1.23
PDPP-3DTP	-4.47	-3.31	1.13

Fig.3 DFT simulation calculation results of PDPP-DTP，PDPP-2DTP and PDPP-3DTP

Fig.4 Ultraviolet-visible-near-infrared absorption spectra and Ipolaron /Ineutral of PDPP-DTP and PDPP-2DTP，PDPP-3DTP at different doping concentrations

Fig.5 Conductivity，seebeck coefficient and PF of the polymer at different doping concentrations

Fig.6 Temperature dependence curve of polymer film under optimal doping conditions

References 43

1	高洁，唐善法，郭海莹，等.石油污染土壤处理新技术——植物型微生物燃料电池的适用性［J］.油田化学，2023，40（2）： 350-355.
	GAO J，TANG S F，GUO H Y，et al.Applicability of new technology for treatment of oil contaminated soil——Plant-based microbial fuel cell［J］.Oilfield Chemistry，2023，40（2）：350-355.
2	曹湘洪.能源转型中我国炼油工业面临的挑战与对策［J］.石油炼制与化工，2021，52（10）：1-9.
	CAO X H.Challenges and countermeasures of China's oil refining industry in transformation of energy utilization［J］.Petroleum Processing and Petrochemicals，2021，52（10）：1-9.
3	黎园.我国天然气化工产业发展现状及前景分析［J］.低碳化学与化工，2024，49（1）：105-112.
	LI Y.Analysis of current development status and prospects of China's natural gas chemical industry［J］.Low-Carbon Chemistry and Chemical Engineering，2024，49（1）：105-112.
4	刘国荣，王春喜，何泽慧.天然气压差发电、光伏发电及太阳能集热技术在油气田中的应用研究［J］.节能与环保，2022（12）：74-76.
	LIU G R，WANG C X，HE Z H.Application research of natural gas pressure difference power generation，photovoltaic power generation and solar energy heat collection technology in oil and gas fields［J］.Energy Conservation and Environmental Protection，2022（12）：74-76.
5	王明华.国内氢能应用场景分析及发展前景预测［J］.石油炼制与化工，2023，54（9）：18-23.
	WANG M H.Application scenarios analysis and development prospect prediction of domestic hydrogen energy［J］.Petroleum Processing and Petrochemicals，2023，54（9）：18-23.
6	张硕，宋强，张玉龙，等.变压吸附提纯氢气的研究进展及应用［J］.辽宁石油化工大学学报，2023，43（6）：30-36.
	ZHANG S，SONG Q，ZHANG Y L，et al.Research progress and application of hydrogen purification by pressure swing adsorption［J］.Journal of Liaoning Petrochemical University，2023，43（6）：30-36.
7	孙阳，李红叶，张洪阳，等.风力发电机能效提升路径综述与思考［J］.当代化工，2023，52（6）：1410-1414.
	SUN Y，LI H Y，ZHANG H Y，et al.Review and consideration on energy efficiency improvement paths of wind turbines［J］.Contemporary Chemical Industry，2023，52（6）：1410-1414.
8	吕昊，张阳，王骏，等.二硫化钼压电材料的能源和环境应用［J］.化工环保，2023，43（4）：440-447.
	LÜ H，ZHANG Y，WANG J，et al.Energy and environmental applications of molybdenum disulfide piezoelectric material［J］.Environmental Protection of Chemical Industry，2023，43（4）：440-447.
9	FORMAN C，MURITALA I K，PARDEMANN R，et al.Estimating the global waste heat potential［J］.Renewable and Sustainable Energy Reviews，2016，57：1568-1579.
10	宗毓东，李鸿冰，丁其军，等.热电发电器件的研究与应用进展［J］.中国材料进展，2023，42（11）：884-895.
	ZONG Y D，LI H B，DING Q J，et al.Research and application progress of thermoelectric power generation devices［J］.Materials China，2023，42（11）：884-895.
11	高丽平.热电材料的研究现状及最新应用［J］.金属功能材料，2023，30（6）：97-102.
	GAO L P.Research status and latest applications of thermoelectric materials［J］.Metallic Functional Materials，2023，30（6）：97-102.
12	TAN G J，ZHAO L D，KANATZIDIS M G.Rationally designing high-performance bulk thermoelectric materials［J］.Chemical Reviews，2016，116（19）：12123-12149.
13	DENG L H，LIU Y R，ZHANG Y Y，et al.Organic thermoelectric materials：Niche harvester of thermal energy［J］.Advanced Functional Materials，2023，33（3）：2210770.
14	ZHANG Y H，HEO Y J，PARK M，et al.Recent advances in organic thermoelectric materials：Principle mechanisms and emerging carbon-based green energy materials［J］.Polymers，2019，11（1）：167.
15	杨思然，毕研峰，赵桂艳.聚吡咯复合材料的制备与应用研究［J］.石油化工高等学校学报，2022，35（2）：43-49.
	YANG S R，BI Y F，ZHAO G Y.Preparation and application of polypyrrole composites［J］.Journal of Petrochemical Universities，2022，35（2）：43-49.
16	LINDORF M，MAZZIO K A，PFLAUM J，et al.Organic-based thermoelectrics［J］.Journal of Materials Chemistry A，2020，8（16）：7495-7507.
17	WU L L，LI H，CHAI H Y，et al.Anion-dependent molecular doping and charge transport in ferric salt-doped P3HT for thermoelectric application［J］.ACS Applied Electronic Materials，2021，3（3）：1252-1259.
18	ZENG H Y，DURAND P，GUCHAIT S，et al.Optimizing chain alignment and preserving the pristine structure of single-ether based PBTTT helps improve thermoelectric properties in sequentially doped thin films［J］.Journal of Materials Chemistry C，2022，10（42）：15883-15896.
19	VIJAYAKUMAR V，ZHONG Y H，UNTILOVA V，et al.Bringing conducting polymers to high order：Toward conductivities beyond 105 S/cm and thermoelectric power factors of 2 mW/（m·K²）［J］.Advanced Energy Materials，2019，9（24）：1900266.
20	DI NUZZO D，FONTANESI C，JONES R，et al.How intermolecular geometrical disorder affects the molecular doping of donor-acceptor copolymers［J］.Nature Communications，2015，6：6460.
21	MUKHOPADHYAYA T，WAGNER J，LEE T D，et al.Solution-doped donor-acceptor copolymers based on diketopyrrolopyrrole and 3，3′-bis（2-（2-（2‐methoxyethoxy）ethoxy）ethoxy）-2，2′-bithiophene exhibiting outstanding thermoelectric power factors with p-dopants［J］.Advanced Functional Materials，2024，34（7）：2309646.
22	LI H，SONG J，XIAO J，et al.Synergistically improved molecular doping and carrier mobility by copolymerization of donor–acceptor and donor–donor building blocks for thermoelectric application［J］.Advanced Functional Materials，2020，30（40）：2004378.
23	LI H，XU Z，SONG J，et al.Single-solution doping enabling dominant integer charge transfer for synergistically improved carrier concentration and mobility in donor–acceptor polymers［J］.Advanced Functional Materials，2022，32（14）：2110047.
24	DING J M，LIU Z T，ZHAO W R，et al.Selenium-substituted DPP polymer for high-performance p-type organic thermoelectric materials［J］.Angewandte Chemie International Edition，2019，58（52）：18994-18999.
25	TANG J H，JI J J，CHEN R S，et al.Achieving efficient p-type organic thermoelectrics by modulation of acceptor unit in photovoltaic π-conjugated copolymers［J］.Advanced Science （Weinheim，Baden-Wurttemberg，Germany），2022，9（4）：e2103646.
26	SONG Y L，DAI X J，ZOU Y，et al.Boosting the thermoelectric performance of the doped DPP-EDOT conjugated polymer by incorporating an ionic additive［J］.Small，2023，19（29）：e2300231.
27	ZHOU X Y，PAN C J，GAO C M，et al.Thermoelectrics of two-dimensional conjugated benzodithiophene-based polymers：Density-of-states enhancement and semi-metallic behavior［J］.Journal of Materials Chemistry A，2019，7（17）：10422-10430.
28	HU Y C，GAO Y F，LI P C，et al.Enhancement of thermoelectric properties of D-A conjugated polymer through constructing random copolymers with more electronic donors［J］.Journal of Polymer Science，2022，60（6）：1002-1012.
29	KARPOV Y，ERDMANN T，STAMM M，et al.Molecular doping of a high mobility diketopyrrolopyrrole–dithienylthieno［3，2-b］thiophene donor–acceptor copolymer with F6TCNNQ［J］.Macromolecules，2017，50（3）：914-926.
30	LIU Z T，HU Y C，LI P C，et al.Enhancement of the thermoelectric performance of DPP based polymers by introducing one 3，4-ethylenedioxythiophene electron-rich building block［J］.Journal of Materials Chemistry C，2020，8（31）：10859-10867.
31	KIM N Y，LEE T S，LEE D Y，et al.Enhanced doping efficiency and thermoelectric performance of diketopyrrolopyrrole-based conjugated polymers with extended thiophene donors［J］.Journal of Materials Chemistry C，2021，9（1）：340-347.
32	MABROUK S，ZHANG M M，WANG Z H，et al.Dithieno［3，2-b：2′，3′-d］pyrrole-based hole transport materials for perovskite solar cells with efficiencies over 18%［J］.Journal of Materials Chemistry A，2018，6（17）：7950-7958.
33	ZHOU J，YIN X X，DONG Z H，et al.Dithieno［3，2-b：2'，3'-d］pyrrole cored p-type semiconductors enabling 20% efficiency dopant-free perovskite solar cells［J］.Angewandte Chemie （International ed.in English），2019，58（39）：13717-13721.
34	ZHANG X，STECKLER T T，DASARI R R，et al.Dithienopyrrole-based donor-acceptor copolymers：Low band-gap materials for charge transport，photovoltaics and electrochromism［J］.Journal of Materials Chemistry，2010，20（1）：123-134.
35	ZHANG Z G，WANG J Z.Structures and properties of conjugated donor-acceptor copolymers for solar cell applications［J］.Journal of Materials Chemistry，2012，22（10）：4178-4187.
36	PAN B，ZHU Y Z，YE D，et al.Improved conversion efficiency in dye-sensitized solar cells based on porphyrin dyes with dithieno［3，2-b：2′，3′-d］pyrrole donor［J］.Dyes and Pigments，2018，150：223-230.
37	LEE H，LI H，KIM Y S，et al.Novel dithienopyrrole-based conjugated copolymers：Importance of backbone planarity in achieving high electrical conductivity and thermoelectric performance［J］.Macromolecular Rapid Communications，2022，43（19）：2200277.
38	LI H，LIU F B，WANG X D，et al.Diketopyrrolopyrrole–thiophene–benzothiadiazole random copolymers：An effective strategy to adjust thin-film crystallinity for transistor and photovoltaic properties［J］.Macromolecules，2013，46（23）：9211-9219.
39	HU L Y，QIAO W Q，QI J，et al.Significant enhancement of photodetector performance by subtle changes in the side chains of dithienopyrrole-based polymers［J］.RSC Advances，2016，6（27）：22494-22499.
40	YASSIN A，LERICHE P，RONCALI J.Synthesis and chain-length dependence of the electronic properties of π-conjugated dithieno［3，2-b：2′，3′-d］pyrrole （DTP） oligomers［J］.Macromolecular Rapid Communications，2010，31（16）：1467-1472.
41	高亦飞，李鹏程，姚军龙.基于苯并［1，2-b：4，5-b'］二噻吩共轭聚合物的合成及热电性能研究［J］.化肥设计，2022，60（2）：22-27.
	GAO Y F，LI P C，YAO J L.Study on the synthesis and thermoelectric properties of conjugation polymers based on benzo ［1，2-b：4，5-b'］dithiophene［J］.Chemical Fertilizer Design，2022，60（2）：22-27.
42	ZUO G Z，LIU X J，FAHLMAN M，et al.High seebeck coefficient in mixtures of conjugated polymers［J］.Advanced Functional Materials，2018，28（15）：1703280.
43	XIA Y J，SUN K，OUYANG J Y.Solution-processed metallic conducting polymer films as transparent electrode of optoelectronic devices［J］.Advanced Materials，2012，24（18）：2436-2440.

[1]	Lele LI, Lisha SHEN, Zhiming TU, Zhuoxin LU, Hongyi TAN, Yi YANG, Changfeng YAN. Preparation of Cu⁃Doped WN Nanoarrays and Study on Their Hydrogen Evolution Performance [J]. Journal of Petrochemical Universities, 2024, 37(4): 57-65.
[2]	Ziye Shen, Lijuan Wang. Li⁃Storage of Li₂ZnTi₃O₈@C⁃N Anode Materials with High Specific Capacities [J]. Journal of Petrochemical Universities, 2022, 35(3): 1-9.
[3]	Bo Zhao, Zhiming Sui, Zhefei Li, Wanying Huo, Kuo Wang, Gangfeng Shen, Xuesong Liu. Effects of S, P, Si Doping on the Evolution of Active Species and NH₃⁃SCR Activity of a VO_x/TiO₂ Catalyst [J]. Journal of Petrochemical Universities, 2021, 34(5): 16-23.
[4]	Zhang Yuntong, Yue Lin, Wang Siyu,et al. Research of Composition and Coking Behavior of Ethylene Cracking Tar [J]. Journal of Petrochemical Universities, 2015, 28(4): 22-26.
[5]	FAN Wen-yu,LI Xiao-chao, WANG Li,YAO Hui,JIN Biao. Preparation of CuO-SnO₂ Gas Sensor and Its Sensitive Effect [J]. Journal of Petrochemical Universities, 2011, 24(2): 18-21.
[6]	LI Qi， QIAO Qing-dong. Conductivity Measurement of Polyanilines With Single Sweep Voltametric Method [J]. Journal of Petrochemical Universities, 2010, 23(4): 48-50.