Organic semiconductor-based thin-film transistors’ (TFTs) charge-carrier mobility has been enhanced up to 25 cm 2 /V s through the improvement of fabrication methods and greater understanding of the microstructure charge-transport mechanism. To expand the practical feasibility of organic semiconductor-based TFTs, their electrical properties should be easily accessed from the fully printed devices through a scalable printing method, such as a roll-to-roll (R2R) gravure. In this study, four commercially available organic semiconductors were separately formulated into gravure inks. They were then employed in the R2R gravure system (silver ink for printing gate and drain–source electrodes and BaTiO 3 ink for printing dielectric layers) for printing 20 × 20 TFT-active matrix with the resolution of 10 pixels per inch on poly(ethylene terephthalate) (PET) foils to attain electrical properties of organic semiconductors a practical printing method. Electrical characteristics (mobility, on–off current ratio, threshold voltage, and transconductance) of the R2R gravure-printed 20 × 20 TFT-active matrices fabricated with organic semiconducting ink were analyzed statistically, and the results showed more than 98% device yield and 50 % electrical variations in the R2R gravure TFT-active matrices along the PET web.

are fabricated by incorporating the vacuum deposition and printing methods utilizing pentacene at 869 MHz, C60 and pentacene at 300 MHz, C60 and tungsten oxide at 800 MHz and indium gallium zinc oxide (IGZO) at 16.7 GHz, respectively. [5][6][7][8] However, due to the weak nature of the signal generated from the smartphone (<1.5 Vpp), none of the aforementioned rectifiers were able to successfully interlock with the smartphone NFC signal. Furthermore, although all roll-to-roll (R2R) printed inorganic ZnO-PAN (polyaniline)-based diodes were reported to wirelessly transmit the operation power to the passive NFC sensor tag using 13.56 MHz, the rectifying efficiency was held to under 50%. [2][3][4] For the ultra high frequency region, in recent years, the printed silicon microparticles-based diodes have demonstrated the ability to interlock with smartphones using a 1.6 GHz signal. [9,10] However, in spite of the aforementioned achievements in rectifier fabrication, DC power harvesting from the coupled NFC signal of smartphones has not been demonstrated yet due to the high turn-on voltage and low rectifying efficiency of the printed diodes. [3,9,10] As such is the case, in order to harvest DC power with greater than 50% efficiency from the weak NFC signal (<1.5 Vpp) of smartphones, printed flexible rectifiers using high-performing semiconducting ink is still imperative in order to develop cost-effective and flexible NFC-sensor devices capable of interlocking with smartphones.The gravure, among well-known scalable printing methods, has been relatively well explored in terms of practicality in printing the rectifying diodes and thin film transistor (TFT)based devices. The method enables the resolution and reliability of overlay printing registration accuracy to be able to be maintained on printed patterns up to ±20 µm. [11] Therefore, in this work, the gravure method has been extensively explored in order to print a Schottky diode for the fabrication of a rectifier able to harvest DC power from the NFC signal of the smartphone. In order to employ the gravure method in printing the Schottky diode, the formulation of semiconducting ink is the most crucial step. The semiconducting layers should be able to render the Ohmic contacts solely with printed silver electrodes, as only silver nanoparticle-based gravure ink is commercially available. Furthermore, the semiconducting ink needs to have an appropriate viscosity and wetting property in order to print a homogeneous Formulating a high-performing semiconducting ink is crucial toward printing a diode for constructing a direct current (DC) power harvesting device, consisting of an antenna, a diode, and a capacitor, that can rectify the coupled weak near field communication (NFC) (13.56 MHz) signal (<1.5 Vpp) generated from smartphones. To achieve such performance, indium gallium zinc oxide (IGZO)-based semiconducting ink is formulated by developing an electroactive binder, poly(4-styrene sulfonic acid). By reducing the turn-on voltage and providing a good rheological character...

Effective control of post-operative inflammation after tissue repair remains a clinical challenge. A tissue repair patch that could appropriately integrate into the surrounding tissue and control inflammatory responses would improve tissue healing. A collagen-based hybrid tissue repair patch has been developed in this work for the local delivery of an anti-inflammatory drug. Dexamethasone (DEX) was encapsulated into PLGA microspheres and then co-electrocompacted into a collagen membrane. Using a simple process, multiple drugs can be loaded into and released from this hybrid composite material simultaneously, and the ratio between each drug is controllable. Anti-inflammatory DEX and the anti-epileptic phenytoin (PHT) were co-encapsulated and released to validate the dual drug delivery ability of this versatile composite material. Furthermore, the Young’s modulus of this drug-loaded collagen patch was increased to 20 KPa using a biocompatible riboflavin (vitamin B2)-induced UV light cross-linking strategy. This versatile composite material has a wide range of potential applications which deserve exploration in further research.