Enhanced Optical Contrast and Switching in Near‐Infrared Electrochromic Devices by Optimizing Conjugated Polymer Oligo(Ethylene Glycol) Sidechain Content and Gel Electrolyte Composition
Enhanced Optical Contrast and Switching in Near‐Infrared Electrochromic Devices by Optimizing Conjugated Polymer Oligo(Ethylene Glycol) Sidechain Content and Gel Electrolyte Composition
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DOI：
10.1002/adfm.202309428
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发表时间：
2023-10
影响因子：
19
通讯作者：
R. Pankow;Brendan Kerwin;Yongjoon Cho;Seonghun Jeong;G. Forti;Bryan Musolino;Changduk Yang;A. Facchetti;T. Marks
中科院分区：
文献类型：
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作者：
R. Pankow;Brendan Kerwin;Yongjoon Cho;Seonghun Jeong;G. Forti;Bryan Musolino;Changduk Yang;A. Facchetti;T. Marks
详细研究了用低聚乙二醇（EGn）侧链官能化共轭聚合物对电致变色器件（ECD）的性能和聚合物-电解质相容性的影响。对一系列具有近红外（NIR）-光学吸收的供体-受体共聚物的电化学进行了广泛的探索，其中供体片段是3，4-亚乙基二氧噻吩（EDOT）或EGn官能化的联噻吩（g2 T），受体片段是用支链烷基或EGn侧链官能化的二酮基吡咯并吡咯（DPP）。接下来制造ECD，并且发现EGn侧链并入必须精细平衡以促进聚合物-电解质相容性并提供有效的离子交换。适当的电解质-阳离子配对和聚合物结构调整提供了2倍的光学对比度增加（从12%到24%）和> 60倍的切换时间减少（从20到0.3 s）。聚合物膜形态/微结构的原子力显微镜（AFM）/掠入射广角X射线散射（GIWAXS）表征揭示了过量的EGn侧链产生大的聚合物微晶，其可以抑制离子交换。最后，飞行时间二次离子质谱（西姆斯）表明侧链/电解质身份不影响电解质渗透到膜中的深度，并且EGn侧链包含增加电解质阳离子吸收。这里报告的关于聚合物电解质离子插入/排出动力学的材料结构设计见解和指南对于开发下一代混合离子电子导电材料具有重要的实用性。
A detailed investigation addressing the effects of functionalizing conjugated polymers with oligo(ethylene glycol) (EGn) sidechains on the performance and polymer‐electrolyte compatibility of electrochromic devices (ECDs) is reported. The electrochemistry for a series of donor‐acceptor copolymers having near‐infrared (NIR)‐optical absorption, where the donor fragment is 3,4‐ethylenedioxythiophene (EDOT) or an EGn functionalized bithiophene (g2T) and the acceptor fragment is diketopyrrolopyrrole (DPP) functionalized with branched alkyl or EGn sidechains, is extensively probed. ECDs are next fabricated and it is found that EGn sidechain incorporation must be finely balanced to promote polymer‐electrolyte compatibility and provide efficient ion exchange. Proper electrolyte‐cation pairing and polymer structural tuning affords a 2x increase in optical contrast (from 12% to 24%) and >60x reduction in switching time (from 20 to 0.3 s). Atomic force microscopy (AFM)/grazing incidence wide‐angle X‐ray scattering (GIWAXS) characterization of the polymer film morphology/microstructure reveals that an over‐abundance of EGn sidechains generates large polymer crystallites, which can suppress ion exchange. Lastly, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) indicates sidechain/electrolyte identity does not influence the electrolyte penetration depth into the films, and EGn sidechain inclusion increases electrolyte cation uptake. The material structural design insight and guidelines regarding the polymer‐electrolyte ion insertion/expulsion dynamics reported here should be of significant utility for developing next‐generation mixed ionic‐electronic conducting materials.