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Solution‐processable highly conductive polymers are of great interest in emerging electronic applications. For p‐doped polymers, conductivities as high a nearly 105 S cm−1 have been reported. In the case of n‐doped polymers, they often fall well short of the high values noted above, which might be achievable, if much higher charge‐carrier mobilities determined could be realized in combination with high charge‐carrier densities. This is in part due to inefficient doping and dopant ions disturbing the ordering of polymers, limiting efficient charge transport and ultimately the achievable conductivities. Here, n‐doped polymers that achieve a high conductivity of more than 90 S cm−1 by a simple solution‐based co‐deposition method are reported. Two conjugated polymers with rigid planar backbones, but with disordered crystalline structures, exhibit surprising structural tolerance to, and excellent miscibility with, commonly used n‐dopants. These properties allow both high concentrations and high mobility of the charge carriers to be realized simultaneously in n‐doped polymers, resulting in excellent electrical conductivity and thermoelectric performance.

The low n-doping efficiency of conjugated polymers with the molecular dopants limits their availability in electrical conductivity, thermoelectrics, and other electric applications. Recently, considerable efforts have focused on improving the ionization of dopants by modifying the structures of host polymers or n-dopants; however, the effect of ionized dopants on the electrical conductivity and thermoelectric performance of the polymers is still a puzzle. Herein, we try to reveal the role of molecular dopant cations on carrier transport through the systematic comparison of two n-dopants, TAM and N-DMBI-H. These two n-dopants exhibit various doping features with the polymer due to their different chemical structure characteristics. For instance, while doping, TAM negligibly perturbs the polymer backbone conformation and microstructural ordering; then after ionization, TAM cations possess weak π-backbone affinity but strong intrinsic affinity with side chains, which enables the doped system to screen the Coulomb potential spatially. Such doping features lead to high carrierization capabilities for TAM-doped polymers and further result in an excellent conductivity of up to 22 ± 2.5 S cm −1 and a power factor of over 80 μW m −1 K −2 , which are significantly higher than the state of the art values of the common n-dopant N-DMBI-H. More importantly, this strategy has also proven to be widely applicable in other doped polymers. Our investigations indicate the vital role of dopant counterions in high electrical and thermoelectric performance polymers and also suggest that, without sacrificing Seebeck coefficients, high conductivities can be realized with precise regulation of the interaction between the cations and the host.

Polymer semiconductors composed of a carbon-based π conjugated backbone have been studied for several decades as active layers of multifarious organic electronic devices. They combine the advantages of the electrical conductivity of metals and semiconductors and the mechanical behavior of plastics, which are going to become one of the futures of modulable electronic materials. The performance of conjugated materials depends both on their chemical structures and the multilevel microstructures in solid states. Despite the great efforts that have been made, they are still far from producing a clear picture among intrinsic molecular structures, microstructures, and device performances. This review summarizes the development of polymer semiconductors in recent decades from the aspects of material design and the related synthetic strategies, multilevel microstructures, processing technologies, and functional applications. The multilevel microstructures of polymer semiconductors are especially emphasized, which plays a decisive role in determining the device performance. The discussion shows the panorama of polymer semiconductors research and sets up a bridge across chemical structures, microstructures, and finally devices performances. Finally, this review discusses the grand challenges and future opportunities for the research and development of polymer semiconductors.

In the past few decades, conjugated polymers have arousedextensive interest in organic electronic applications. The electrical performance of conjugated polymers has ac loser elationship with their backbonec onformation. The conformation of the polymer backbones trongly affects the pelectron delocalization along polymer chains, the energy band gap, interchain interactions, and further affects charge transport properties. To realize ar igid coplanar backbone that usually possesses efficient intrachain charget ransport properties and enhanced p-p stackings, such conformation control becomes au seful strategy to achieve high-performance (semi)conducting polymers. This minireview summarizes the most important polymer structures through conformation control at the molecular level, and then divides these rigid coplanar conjugated polymers into three categories:1)noncovalent interactions locked conjugated polymers;2)double-bondl inked conjugated polymers; 3) ladder conjugated polymers. The effect of the conformation controlo np hysical nature, optoelectronic properties, and their devicep erformance is also discussed, as well as the challenges of chemical synthesis and structuralc haracterization.

Different backbone shape of BDOPV-based polymers generates distinct aggregation structures in dilute solutions, which could be retained into the solid-state microstructures, further exhibiting different electron mobility and doping efficiency.

The role of solution aggregates on the charge transport process of conjugated polymers in electronic devices has gained increasing attention; however, the correlation of the charge carrier mobilities between the solution aggregates and the solid‐state films remains elusive. Herein, three polymers, FBDOPV‐2T, FBDOPV‐2F2T, and FBDOPV‐4F2T, are designed and synthesized with distinct aggregation behavior in solution. By combining contact‐free ultrafast terahertz (THz) spectroscopy and field‐effect transistor measurements, we track the charge carrier mobility of the aggregates of these polymers from the solution to the thin‐film state. Remarkably, the mobility of these three polymers is found to follow nearly the same trend (FBDOPV‐2T>FBDOPV‐2F2T≫FBDOPV‐4F2T) in both solutions and thin‐film states. The quantitative mobility correlation indicates that the charge transport properties of solution aggregates play a critical role in determining the thin‐film charge transport properties and final device performance. Our results highlight the importance of investigating and controlling solution aggregation structures towards efficient organic electronic devices.