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Effect of processing conditions on additive DISC patterning of P3HT films
摘要： There is a critical need to develop a method to pattern semiconducting polymers for device applications on the sub-micrometer scale. Dopant induced solubility control (DISC) patterning is a recently published method for patterning semiconductor polymers that has demonstrated sub-micron resolution. DISC relies on the sequential addition of molecular dopants (here 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ)) to the conjugated polymer. In doped areas, the conjugated polymer is protected from dissolution while in undoped areas, the polymer dissolves into solution. Here we examine factors that affect the resolution of the developed pattern. Two factors are determined to be critical to pattern resolution, the initial crystallinity of the polymer, here poly(3-hexylthiophene) (P3HT), and the quality of the development solvent. We find that dopants diffuse more readily in highly crystalline films than in amorphous films of P3HT and that dopant diffusion reduces the fidelity of the resulting pattern. We also find that the choice of development solvent affects both the fidelity of the pattern and dopant distribution within the patterned polymer domains. Finally, we show that a dopant that diffuses more slowly than F4TCNQ in the P3HT film can be used to pattern the film with higher fidelity. These results together provide a road map for optimizing additive DISC patterning for any polymer/dopant pair.
关键词： crystallinity,semiconducting polymers,development solvent,pattern fidelity,P3HT,DISC patterning,F4TCNQ
更新于2025-11-21 11:08:12
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Ambipolar Conjugated Polymers with Ultrahigh Balanced Hole and Electron Mobility for Printed Organic Complementary Logic via a Two-Step C?H Activation Strategy
摘要： High mobility ambipolar conjugated polymers are seriously absent regardless their great potential for flexible and printed plastic devices and circuits. Here, ambipolar polymers with ultrahigh balanced hole and electron mobility are developed via a two-step C–H activation strategy. Diketopyrrolopyrrole-benzothiadiazole-diketopyrrolopyrrole (DBD) and its copolymers with thiophene/selenophene units (short as PDBD-T and PDBD-Se) are used as examples. PDBD-Se exhibits highly efficient ambipolar transport with hole and electron mobility up to 8.90 and 7.71 cm2 V?1 s?1 in flexible organic field-effect transistors, presenting a milestone for ambipolar copolymer screening. Based on this performance metrics and good solubility, PDBD-Se is investigated as inkjet-printable semiconductor ink for organic complementary logic circuits. Under ambient processing, maximum hole and electron mobilities reach 6.70 and 4.30 cm2 V?1 s?1, respectively. Printed complementary inverter and NAND gates with transition voltages near VDD/2 are fabricated, providing an easy-handling, general material for printed electronics and logic.
关键词： ambipolar transport,semiconducting polymers,organic circuits,inkjet printing,C–H activation
更新于2025-09-23 15:22:29
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Structure and Conformation of a Crystalline P3HT Film Adsorbed on an Alkanethiol Self-Assembled Monolayer Deposited on Gold
摘要： All-atom molecular dynamics simulations are performed to investigate the structural and conformational properties of a regioregular poly(3-hexylthiophene) (P3HT) crystal in the presence of a gold (Au) substrate terminated with an n-alkanethiol self-assembled monolayer (SAM). The employed orientation of the P3HT crystals deposited on the SAM is the edge-on, since this orientation is believed to be the most energetically favorable and stable, also yielding the highest charge carrier mobility in organic thin-film transistors. The unit cell of the overall Au/SAM interfacial layer is obtained through detailed ab initio calculations. Systems with a varying number of P3HT stacks on the Au/SAM substrate are studied with an all-atom force field in order to elucidate the effect of polymer thickness on the structural properties of the system. All final structures are found to be stable and well-equilibrated. Insights into the P3HT crystal structure are provided for the P3HT layers in direct contact with the SAM, but also for those deeper in the polymer film. According to the simulations, the majority of conformational and packing properties of the P3HT film are practically similar to those of the bulk crystalline P3HT material, implying that its structure remains unaffected by the presence of the underlying Au/SAM substrate.
关键词： DFT calculations,semiconducting polymers,molecular dynamics simulations,self-assembled monolayers,P3HT
更新于2025-09-23 15:19:57
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Optically Tunable Field Effect Transistors with Conjugated Polymer Entailing Azobenzene Groups in the Side Chains
摘要： Semiconducting conjugated polymers with photoswitching behavior are highly demanded for field-effect transistors (FETs) with tunable electronic properties. Herein a new design strategy is established for photoresponsive conjugated polymers by incorporating photochromic units (azobenzene) into the flexible side alkyl chains. It is shown that azobenzene groups in the side chains of the DPP (diketopyrrolopyrrole)-quaterthiophene polymer (PDAZO) can undergo trans/cis photoisomerization in fully reversible and fast manner. Optically tunable FETs with bistable states are successfully fabricated with thin films of PDAZO. The drain-source currents are reduced by 80.1% after UV light irradiation for ≈28 s, which are easily restored after further visible light irradiation for ≈33 s. Such fast optically tunable FETs are not reported before. Moreover, such current photomodulation can be implemented for multiple light irradiation cycles with good photofatigue resistance. Additionally, thin film charge mobility of PDAZO can be reversibly modulated by alternating UV and visible light irradiations. On the basis of theoretical calculations and GIWAXS data, it is hypothesized that the dipole moment and configuration changes associated with the trans-/cis-photoisomerization of azobenzene groups in PDAZO can affect the respective intra-chain and inter-chain charge transporting, which is responsible for the optically tunable behavior for FETs with thin films of PDAZO.
关键词： side alkyl chains,semiconducting polymers,thin-film field-effect transistors,azobenzene,photoresponsiveness
更新于2025-09-19 17:15:36
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Dodecaborane-Based Dopants Designed to Shield Anion Electrostatics Lead to Increased Carrier Mobility in a Doped Conjugated Polymer
摘要： One of the most effective ways to tune the electronic properties of conjugated polymers is to dope them with small-molecule oxidizing agents, creating holes on the polymer and molecular anions. Undesirably, strong electrostatic attraction from the anions of most dopants localizes the holes created on the polymer, reducing their mobility. Here, a new strategy utilizing a substituted boron cluster as a molecular dopant for conjugated polymers is employed. By designing the cluster to have a high redox potential and steric protection of the core-localized electron density, highly delocalized polarons with mobilities equivalent to films doped with no anions present are obtained. AC Hall effect measurements show that P3HT films doped with these boron clusters have conductivities and polaron mobilities roughly an order of magnitude higher than films doped with F4TCNQ, even though the boron-cluster-doped films have poor crystallinity. Moreover, the number of free carriers approximately matches the number of boron clusters, yielding a doping efficiency of ≈100%. These results suggest that shielding the polaron from the anion is a critically important aspect for producing high carrier mobility, and that the high polymer crystallinity required with dopants such as F4TCNQ is primarily to keep the counterions far from the polymer backbone.
关键词： mobility,molecular dopants,Coulomb screening,semiconducting polymers,dodecaboranes
更新于2025-09-19 17:15:36
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Photo- and electroluminescence features of films and field effect transistors based on inorganic perovskite nanocrystals embedded in a polymer matrix
摘要： The optical and electrical properties of films and field-effect transistors (FETs) based on pure MEH-PPV, neat CsPbBr3 nanocrystals (NCs), and MEH-PPV:CsPbBr3 NCs composites with different contents of CsPbBr3 NCs are investigated. The films were characterized by absorbance, atomic-force microscope and current-voltage characteristics (I-Vs) techniques. Relative PL and EL intensities and PL spectra of the pure MEH-PPV, neat CsPbBr3 NCs and MEH-PPV:CsPbBr3 NCs films were measured at 300 K at various levels of optical and electrical excitation power; these dependencies of the PL and EL intensities turned out to be sublinear and superlinear respectively. FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films exhibit I-Vs at 290 – 100 K a dominant hole transport mechanism. The mobility of charge carriers was determined at 290 K for neat CsPbBr3 NCs (for electrons: 2.7 10-2 cm2/Vs) and MEH-PPV:CsPbBr3 NCs (1:1) (for holes: 9 cm2/Vs). The temperature dependence of the hole mobility μFET(T) of FETs based on MEH-PPV:CsPbBr3 NCs (1:1) films characteristic of the hopping mode. It was found that the superlinearity of the dependence of EL of MEH-PPV:CsPbBr3 NCs LE-FETs at 290 K increases with increasing concentration of CsPbBr3 NCs due to efficient energy transfer between CsPbBr3 NCs and the MEH-PPV polymer matrix, and also because of the probability of electron tunneling through the potential barrier to electrode. It is expected that the obtained MEH-PPV:CsPbBr3 NCs nanocomposite films will be useful for efficient applications in nanotechnology LEDs, FETs and LE-FETs.
关键词： Energy transfer,Field-effect transistors,Semiconducting polymers,Photo- and electroluminescence,Charge carrier mobility,Inorganic perovskite nanocrystals
更新于2025-09-16 10:30:52
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Nanococktail Based on AIEgens and Semiconducting Polymers: A Single Laser Excited Image-Guided Dual Photothermal Therapy
摘要： Semiconducting polymers (SPs)-based dual photothermal therapy (PTT) obtained better therapeutic effect than single PTT due to its higher photothermal conversion efficiency. However, most dual PTT need to use two lasers for heat generation, which brings about inconvenience and limitation to the experimental operations. Herein, we report the development of “nanococktail” nanomaterials (DTPR) with 808 nm-activated image-guided dual photothermal properties for optimized cancer therapy. Methods: In this work, we co-encapsulated AIEgens (TPA-BDTO, T) and SPs (PDPPP, P) by using maleimide terminated amphiphilic polymer (DSPE-PEG2000-Mal, D), then further conjugated the targeting ligands (RGD, R) through “click” reaction. Finally, such dual PTT nanococktail (termed as DTPR) was constructed. Results: Once DTPR upon irradiation with 808 nm laser, near-infrared fluorescence from T could be partially converted into thermal energy through fluorescence resonance energy transfer (FRET) between T and P, coupling with the original heat energy generated by the photothermal agent P itself, thus resulting in image-guided dual PTT. The photothermal conversion efficiency of DTPR reached 60.3% (dual PTT), much higher as compared to its inherent photothermal effect of only 31.5% (single PTT), which was further proved by the more severe photothermal ablation in vitro and in vivo upon 808 nm laser irradiation. Conclusion: Such smart “nanococktail” nanomaterials could be recognized as a promising photothermal nanotheranostics for image-guided cancer treatment.
关键词： semiconducting polymers,aggregation-induced emission fluorogens,fluorescence resonance energy transfer,A single laser,dual photothermal therapy
更新于2025-09-16 10:30:52
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Reference Module in Materials Science and Materials Engineering || Chemical and Biological Sensors from Conducting and Semiconducting Polymers
摘要： The need for cheaper, faster, and more accurate measurements in chemical and biological fields has been a driving force for the development of new sensing devices: chemical and biological sensors. These analytical devices comprise a chemical or a biological recognition element, able to interact specifically with an analyte or a target, and a transducer, which converts the recognition event into a measurable signal. On the basis of the transduction principle, chemical and biological sensors can be classified into three major classes: electrochemical, optical, and piezoelectric. The possible range of analytes is almost limitless: from simple molecules to very complex ones.
关键词： electrochemical,biological sensors,optical,chemical sensors,semiconducting polymers,conducting polymers,piezoelectric
更新于2025-09-10 09:29:36
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A suspended 3-omega technique to measure the anisotropic thermal conductivity of semiconducting polymers
摘要： Anisotropic thermal conductivity can complicate the performance of semiconducting polymer thin-films in applications such as thermoelectrics and photovoltaics. Anisotropic measurements of low thermal conductivity polymers are challenging, and there are a limited number of appropriate measurement techniques. Suspended film 3-omega is an appropriate technique but has often required unfavorable microfabrication. Herein, we report on the utility of the suspended 3-omega technique that uses shadow masking, and no other microfabrication techniques, in performing anisotropic (in-plane and through-plane) thermal conductivity measurements of polymer films. We report on the necessary conditions for the validity of the 1D suspended-film heat transfer model and provide experimental guidelines for in-plane thermal conductivity measurements of polymer thin-films. Furthermore, for the first time, we report the anisotropic thermal conductivities of N2200 and a low molecular weight P3HT, which are two common n-type and p-type semiconducting polymers. Measured thermal conductivities are compared with predictions from the conventional Cahill-Pohl model and a recent empirical model that more accurately predicts the temperature dependence.
关键词： semiconducting polymers,thermal conductivity measurements,3-omega technique,anisotropic thermal conductivity,shadow masking
更新于2025-09-10 09:29:36
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The Origin of the π-π Spacing Change upon Doping of Semiconducting Polymers
摘要： While there is agreement about the local structural order of semiconducting polymers such as poly(3-hexylthiophene) (P3HT), there is still debate over the impact of molecular doping. One prevalent interpretation is that dopant molecules intercalate in the π-π stacking of crystallites; however, this idea has recently been challenged. We present here electron diffraction measurements of P3HT doped with the two dopants 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) and molybdenum tris[1-(methoxycarbonyl)-2-(trifluoromethyl)-ethane-1,2-dithiolene] (Mo(tfd-CO2Me)3), which have considerably different sizes and shapes, processed by different doping techniques. We observe a reduction in the π-π spacing of P3HT upon doping with both dopant molecules and doping techniques. These data are not consistent with both of the dopants intercalating in the π-π stacks and an alternative explanation is, therefore, required to explain these results. Density functional theory calculations for P3HT model oligomers suggest that the polaron delocalizes between adjacent chains and thus leads to attractive forces that reduce the π-π spacing, without the physical presence of any dopant molecules. Our study emphasizes that not only geometric effects induced by dopant molecules lead to the observed reduction of π-π spacing, but the charging itself.
关键词： semiconducting polymers,electron diffraction,π-π spacing,F4TCNQ,Mo(tfd-CO2Me)3,density functional theory,molecular doping,P3HT
更新于2025-09-10 09:29:36