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Abstract Patterned semiconductors are essential for the fabrication of nearly all electronic devices. Over the last two decades, semiconducting polymers (SPs) have received enormous attention due to their potential for creating low‐cost flexible electronic devices, while development of scalable patterning methods capable of producing sub‐μm feature sizes has lagged. A novel method for patterning SPs termed Projection Photothermal Lithography (PPL) is presented. A lab scale PPL microscope is built and it is demonstrated that rapid (≈4 cm²h⁻¹) and large single exposure area (≈0.69 mm²) sub‐μm patterns can be obtained optically. Polymer domains are selectively removed via a photo‐induced temperature gradient that enables dissolution. It is hypothesized that commercial‐scale patterning with a throughput of≈5 m²h⁻¹and resolution of<1μm could be realized through optimization of optical components. 

Abstract Molecular doping of conjugated polymers causes bleaching of the neutral absorbance and results in new polaron absorbance transitions in the mid and near infrared. Here, the concentration dependent changes in the spectra for a series of molecularly doped diketopyrrolopyrrole (DPP) co‐polymers with a series of ultra‐high electron affinity cyanotrimethylenecyclopropane‐based dopants is analyzed. With these strong dopants the polaron mole fraction (Θ) reaches saturation. Analysis of the full spectrum enables separation of neutral and polaron signals and quantification of the polaron mole fraction using a simple noninteracting site model. The peak ratios for both neutral and polaron peaks change systematically with increasing polaron mole fraction for all measured polymers. Analysis of the spectral changes indicates that the polaron mole fraction can be quantified to within 5%. While the total change in the absorbance spectrum with increasing polaron mole fraction is linear, the lowest energy polaron peak (P1) grows nonlinearly, which indicates increased polarization/delocalization. Molecular doping of polymers that form either H‐ or J‐aggregates shows systematically different spectral changes in the vibronic peak ratios of the neutral spectra and provides insights into the polymer configuration at undoped sites in the film. 

Abstract Recent development of dopant induced solubility control (DISC) patterning of polymer semiconductors has enabled direct‐write optical patterning of poly‐3‐hexylthiophene (P3HT) with diffraction limited resolution. Here, the optical DISC patterning technique to the most simple circuit element, a wire, is applied. Optical patterning of P3HT and P3HT doped with the molecular dopant 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) wires with dimensions of 20–70 nm thickness, 200–900 nm width, and 40 μm length is demonstrated. In addition, optical patterning of wire patterns like “L” bends and “T” junctions without changing the diameter or thickness of the wires at the junctions is demonstrated. The wires themselves show up to 0.034 S cm^‐1conductance when sequentially doped. It is also demonstrated that a P3HT nanowire can be doped, de‐doped, and re‐doped from solution without changing the dimension of the wire. The combined abilities to optically pattern and reversibly dope a polymer semiconductor represents a full suite of patterning steps equivalent to photolithography for inorganic semiconductors.