Doping-induced solubility control is a patterning technique for semiconducting polymers, which utilizes the reduction in polymer solubility upon p-type doping to provide direct, optical control of film topography and doping level. In situ direct-write patterning and imaging are demonstrated, revealing sub-diffraction-limited topographic features. Photoinduced force microscopy shows that doping level can be optically modulated with similar resolution.

Polymer‐based organic semiconductors inherently facilitate solution processing and have the mechanical robustness necessary for printable and large area applications. In order to achieve large area solution‐processed high‐performance polymer based devices, controlling the crystallization and self‐assembly behavior of the polymer thin films through solution processing method is desirable. Here, well controlled diketopyrrolopyrrole‐thieno[3,2‐b]thiophene copolymer (DPPT‐TT) thin films are developed using slot die coating controlled self‐assembly. The thin film morphologies and microstructure are investigated in details. This well‐defined morphology is rationalized in terms of the strong intermolecular interactions. The organic thin film transistors (OTFTs) with these controlled thin films are fabricated and exhibited charge carrier mobilities of 4.6–7.2 cm2 V−1 s−1 for the slot die coating controlled devices when measured in ambient air and up to 8.9–10.2 cm2 V−1 s−1 when measured in nitrogen. When applying native grown AlO x as gate dielectric, the OTFT achieves a mobility of 2.0 cm2 V−1 s−1 at the operating voltage ≤−3 V.

A cylindrical lens telescope tilted-pulse-front pumping scheme was proposed for high energy terahertz (THz) pulse generation. This scheme allows higher pump energy to be used with lower saturation effects under high pump fluence, and higher THz generation efficiency was achieved within large range of pump energy. The optimum pump pulse duration and crystal cooling temperature for THz generation in LiNbO₃ (LN) crystal were also researched systematically. Excited by 800-nm laser, up to 0.19 mJ THz pulse energy and 0.27% conversion efficiency was demonstrated under 800-nm 400-fs laser excitation with ~100-mJ pulse energy and 150-K LN cooling temperature.

Intrinsically heat-sealable polyimides with atomic oxygen (AO) resistance (ARPIs) were synthesized from 2,3,3′,4′-oxydiphthalic anhydride (aODPA), 2,5-bis[(4-aminophenoxy)phenyl]diphenylphosphine oxide (BADPO), and para-phenylenediamine (PDA). The effects of the molecular structure and diamine ratio were investigated on the properties of the ARPI, including mechanical property, thermal property, heat sealability, and AO resistance. Heat sealability and AO resistance were realized for the ARPI film by combining the asymmetry of the aODPA moiety and the passivated layer forming characteristic of diphenylphosphine phosphine oxide group. Meanwhile, the deficiency of low mechanical strength and thermal resistance, commonly existing in a completely BADPO-derived polyimide system, was remedied effectively by the higher reactivity and rigidity of PDA.