Organic thin film transistors: Materials, processes and devices

Solid State NMR Spectroscopy a Valuable Technique for Structural Insights of Advanced Thin Film Materials: A Review

Solid-state NMR has proven to be a versatile technique for studying the chemical structure, 3D structure and dynamics of all sorts of chemical compounds. In nanotechnology and particularly in thin films, the study of chemical modification, molecular packing, end chain motion, distance determination and solvent-matrix interactions is essential for controlling the final product properties and applications. Despite its atomic-level research capabilities and recent technical advancements, solid-state NMR is still lacking behind other spectroscopic techniques in the field of thin films due to the underestimation of NMR capabilities, availability, great variety of nuclei and pulse sequences, lack of sensitivity for quadrupole nuclei and time-consuming experiments. This article will comprehensively and critically review the work done by solid-state NMR on different types of thin films and the most advanced NMR strategies, which are beyond conventional, and the hardware design used to overcome the technical issues in thin-film research.

Preparation and Application of Organic-Inorganic Nanocomposite Materials in Stretched Organic Thin Film Transistors

High-transparency soluble polyimide with COOH and fluorine functional groups and TiO₂-SiO₂ composite inorganic nanoparticles with high dielectric constants were synthesized in this study. The polyimide and inorganic composite nanoparticles were further applied in the preparation of organic-inorganic hybrid high dielectric materials as the gate dielectric for a stretchable transistor. The optimal ratio of organic and inorganic components in the hybrid films was investigated. In addition, Jeffamine D2000 and polyurethane were added to the gate dielectric to improve the tensile properties of the organic thin film transistor (OTFT) device. PffBT4T-2OD was used as the semiconductor layer material and indium gallium liquid alloy as the upper electrode. Electrical property analysis demonstrated that the mobility could reach 0.242 cm²·V⁻¹·s⁻¹ at an inorganic content of 30 wt.%, and the switching current ratio was 9.04 × 10³. After Jeffamine D2000 and polyurethane additives were added, the mobility and switching current could be increased to 0.817 cm²·V⁻¹·s⁻¹ and 4.27 × 10⁵ for Jeffamine D2000 and 0.562 cm²·V⁻¹·s⁻¹ and 2.04 × 10⁵ for polyurethane, respectively. Additives also improved the respective mechanical properties. The stretching test indicated that the addition of polyurethane allowed the OTFT device to be stretched to 50%, and the electrical properties could be maintained after stretching 150 cycles.

Monotype Organic Dual Threshold Voltage Using Different OTFT Geometries

It is well known that organic thin film transistor (OTFT) parameters can be shifted depending on the geometry of the device. In this work, we present two different transistor geometries, interdigitated and Corbino, which provide differences in the key parameters of devices such as threshold voltage (VT), although they share the same materials and fabrication procedure. Furthermore, it is proven that Corbino geometries are good candidates for saturation-mode current driven devices, as they provide higher ION/IOFF ratios. By taking advantage of these differences, circuit design can be improved and the proposed geometries are, therefore, particularly suited for the implementation of logic gates. The results demonstrate a high gain and low hysteresis organic monotype inverter circuit with full swing voltage at the output.