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1. Enhancing Electrical Conductivity and Power Factor in Poly‐Glycol‐Bithienylthienothiophene with Oligoethylene Glycol Side Chains Through Tris (pentafluorophenyl) Borane Doping

   https://doi.org/10.1002/adfm.202400469  

   Chen, Nan Louise; Mukhopadhyay, Tushita; Song, Yunjia; Griggs, Sophie; Kousseff, Christina J; McCulloch, Iain; Katz, Howard E (April 2024, Advanced Functional Materials)

   Katz, Howard E (Ed.)

   Abstract Doping of organic semiconductors has served as an effective method to achieve high electrical conductivity and large thermoelectric power factor. This is of importance to the development of flexible/wearable electronics and green energy‐harvesting technologies. The doping impact of the Lewis acid tris (pentafluorophenyl) borane (BCF) on the thermoelectric performance of poly(2‐(4,4′‐bis(2‐methoxyethoxy)‐5′‐methyl‐[2,2′‐bithiophen]‐5‐yl)‐5‐methylthieno[3,2‐b]thiophene (pgBTTT), a thiophene‐based polymer featuring oligoethylene glycol side chains is investigated. Tetrafluorotetracyanoquinodimethane (F4TCNQ), a well‐established dopant, is utilized as a comparison; however, its inability to co‐dissolve with pgBTTT in less polar solvents hinders the attainment of higher doping levels. Consequently, a comparative study is performed on the thermoelectric behavior of pgBTTT doped with BCF and F4TCNQ at a very low doping level. Subsequent investigation is carried out with BCF at higher doping levels. Remarkably, at 50 wt% BCF doping level, the highest power factor of 223 ± 4 µW m⁻¹K²is achieved with an electrical conductivity of 2180 ± 360 S cm⁻¹and a Seebeck coefficient of 32 ± 1.3 µV K⁻¹. This findings not only contribute valuable insights to the dopant interactions with oxygenated side chain polymers but also open up new avenues for high conductivity thermoelectric polymers in flexible electronic applications. 

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2. Clarification of Mn ²⁺ Doping of CH ₃ NH ₃ PbBr ₃ Perovskite Magic‐Sized Clusters

   https://doi.org/10.1002/cnma.202500288  

   Zeitz, David C; Creech, Sarah A; Khvichia, Mariam; Zhang, Jin Z (July 2025, ChemNanoMat)

   Mn²⁺doping of CsPbBr₃perovskite magic‐sized clusters (PMSCs) has been reported previously, where PMSCs with first excitonic absorption and photoluminescence (PL) around 425 nm were reported originally, followed by Mn²⁺‐doped PMSCs with host absorption and PL around 400 nm. There, the observed 25 nm blueshift was attributed to smaller PMSCs or the Cl⁻ions introduced by MnCl₂as dopant precursor. However, subsequent studies suggest that the 400 nm band may instead be due to ligand‐assisted metal halide molecular clusters (MHMCs), which lack the A component of perovskite. This raises the question whether the originally claimed Mn²⁺‐doped PMSCs are actually MHMCs. To unambiguously address this issue, Mn²⁺‐doped CH₃NH₃PbBr₃PMSCs were synthesized with PL at both 440 nm, attributed to the PMSC, and at 600 nm, attributed to Mn²⁺. Blueshifting of the host absorption and PL bands due to Cl⁻codoping is avoided by selecting MnBr₂as dopant precursor rather than MnCl₂. Dopant incorporation into PMSCs is further supported by PL excitation, time‐resolved PL, and electron paramagnetic resonance studies. This work provides direct and strong evidence of successful Mn²⁺doping in PMSCs. 

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3. 3,4,5‐Trimethoxy Substitution on an N‐DMBI Dopant with New N‐type Polymers: Polymer‐Dopant Matching for Improved Conductivity‐Seebeck Coefficient Relationship

   https://doi.org/10.1002/anie.202110505  

   Han, Jinfeng; Chiu, Arlene; Ganley, Connor; McGuiggan, Patricia M.; Thon, Susanna M.; Clancy, Paulette; Katz, Howard E. (October 2021, Angewandte Chemie International Edition)

   null (Ed.)

   Achieving high electrical conductivity and thermoelectric power factor simultaneously for n-type organic thermoelectrics is still challenging. By constructing two new acceptor-acceptor n-type conjugated polymers with different backbones and introducing the 3,4,5-trimethoxyphenyl group to form the new n-type dopant 1,3-dimethyl-2-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1H-benzo[d]imidazole (TP-DMBI), high electrical conductivity of 11 S cm-1 and power factor of 32 μW m-1 K-2 are achieved. Calculations using Density Functional Theory show that TP-DMBI presents a higher singly occupied molecular orbital (SOMO) energy level of -1.94 eV than that of the common dopant 4-(1, 3-dimethyl-2, 3-dihydro-1H-benzoimidazol-2-yl) phenyl) dimethylamine (N-DMBI) (-2.36 eV), which can result in a larger offset between the SOMO of dopant and lowest unoccupied molecular orbital (LUMO) of n-type polymers, though that effect may not be dominant in the present work. The doped polymer films exhibit higher Seebeck coefficient and power factor than films using N-DMBI at the same doping levels or similar electrical conductivity levels. Moreover, TP-DMBI doped polymer films offer much higher electron mobility of up to 0.53 cm2 V-1 s-1 than films with N-DMBI doping, demonstrating the potential of TP-DMBI, and 3,4,5-trialkoxy DMBIs more broadly, for high performance n-type organic thermoelectrics. 

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4. Highly Conductive Polyoxanorbornene‐Based Polymer Electrolyte for Lithium‐Metal Batteries

   https://doi.org/10.1002/advs.202302932  

   An, So Young; Wu, Xinsheng; Zhao, Yuqi; Liu, Tong; Yin, Rongguan; Ahn, Jung Hyun; Walker, Lynn M.; Whitacre, Jay F.; Matyjaszewski, Krzysztof (September 2023, Advanced Science)

   Abstract This present study illustrates the synthesis and preparation of polyoxanorbornene‐based bottlebrush polymers with poly(ethylene oxide) (PEO) side chains by ring‐opening metathesis polymerization for solid polymer electrolytes (SPE). In addition to the conductive PEO side chains, the polyoxanorbornene backbones may act as another ion conductor to further promote Li‐ion movement within the SPE matrix. These results suggest that these bottlebrush polymer electrolytes provide impressively high ionic conductivity of 7.12 × 10⁻⁴S cm⁻¹at room temperature and excellent electrochemical performance, including high‐rate capabilities and cycling stability when paired with a Li metal anode and a LiFePO₄cathode. The new design paradigm, which has dual ionic conductive pathways, provides an unexplored avenue for inventing new SPEs and emphasizes the importance of molecular engineering to develop highly stable and conductive polymer electrolytes for lithium‐metal batteries (LMB). 

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5. Achieving High Performance Stretchable Conjugated Polymers via Donor Structure Engineering

   https://doi.org/10.1002/marc.202300169  

   Wu, Ning; Huang, Gang; Huang, Hua; Wang, Yunfei; Gu, Xiaodan; Wang, Xiaohong; Qiu, Longzhen (September 2023, Macromolecular Rapid Communications)

   Abstract A backbone engineering strategy is developed to tune the mechanical and electrical properties of conjugated polymer semiconductors. Four Donor–Acceptor (D–A) polymers, named PTDPPSe, PTDPPTT, PTDPPBT, and PTDPPTVT, are synthesized using selenophene (Se), thienothiophene (TT), bithiophene (BT), and thienylenevinylenethiophene (TVT) as the donors and siloxane side chain modified diketopyrrolopyrrole (DPP) as acceptor. The influences of the donor structure on the polymer energy level, film morphology, molecular stacking, carrier transport properties, and tensile properties are all examined. The films of PTDPPSe show the best stretchability with crack‐onset‐strain greater than 100%, but the worst electrical properties with a mobility of only 0.54 cm² V⁻¹ s⁻¹. The replacement of the Se donor with larger conjugated donors, that is, TT, BT, and TVT, significantly improves the mobility of conjugated polymers but also leads to reduced stretchability. Remarkably, PTDPPBT exhibits moderate stretchability with crack‐onset‐strain ≈50% and excellent electrical properties. At 50% strain, it has a mobility of 2.37 cm²V⁻¹ s⁻¹parallel to the stretched direction, which is higher than the mobility of most stretchable conjugated polymers in this stretching state. 

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