Organic TFTs have been developed for a broad range of display and integrated circuit applications on flexible, plastic substrates. For display applications organic TFTs have reached an advanced stage of industrialisation. Our industrial partner, Plastic Logic, manufactures flexible displays comprising more than 1 million OTFTs on a plastic substrate for applications in lightweight, robust electronic readers. In contrast to displays circuit applications of OTFTs have been much harder to realize. This is mainly due to the poor switching performance of printed OTFTs arising as a consequence of the relatively low mobility of organic semiconductors (which in spite of dramatic improvements in recent years is still "only" on the order of 1 cm2/Vs) and the low resolution of common graphic arts based printing techniques. Our approach to overcome the critical performance issues of printed electronics has been to develop a high-resolution printing-based manufacturing process for OTFTs (self aligned printing (SAP) / self-aligned gate (SAG) technology) (Noh et al., Nature Nanotechnology 2, 784 (2007)), which allows fabrication of TFTs with submicrometer channel lengths and low parasitic gate capacitance by simple inkjet printing techniques. In the EPSRC/CIKC funded PRIME project we developed this technology into a controlled technology platform for fabrication of integrated circuits with typically 100 TFTs. The number of TFTs is limited by our university fabrication and testing infrastructure. The PRIME project had two main technological objectives: (a) to establish manufacturability of the previously developed SAP/SAG process for downscaling printed organic TFTs and (b) to integrate both p-type and n-type organic semiconductors into such downscaled, printed TFTs to allow fabrication of high yielding, low power printed CMOS circuits. The objective of the proposed follow-on funding project is to commercialize this technology platform in a specific integrated circuit application that is compatible with the limited integration level that we can realistically achieve with our current fabrication infrastructure (about 100 elements).

Organic electronic materials are widely used in LEDs, transistors and, though less advanced, in solar cells. Organic semiconductor devices are generally divided into two classes: those made by vacuum deposition of so-called 'small molecules' and those made by solution-processing of film-forming materials (typically polymers). The UK community, following some of the early work at Cambridge has tended to concentrate on the latter class of materials. The rationale for this is two-fold. Firstly, in terms of translation to large-scale manufacture, direct low-temperature solution processing of active semiconductors is very attractive for low-cost processing, particularly where patterning can be carried out by direct printing (ink-jet printing has been developed, for example, for deposition of red-, green- and blue-emitting materials in full colour displays). Secondly, solution processing presents challenges and opportunities for the formation of useful device structures. In some respects it is awkward - it is generally difficult to assemble multiple layers of organic semiconductor to make conventional laminar heterostructures because solvents are typically not sufficiently specific to allow successive layer depositions without disturbing lower layers - but in other respects, there are real opportunities to generate architectures that would be very difficult to make conventionally. For example, interpenetrating networks of electron-accepting and hole-accepting polymers are required for photovoltaic devices, so that light absorbed throughout the thickness of the semiconductor layer can generated excitons close enough to a region of heterojunction to generate separated charges. The rapid progress made over the last 10 years has taken the field to a level where device performance already sustains a fledgling industry. Basic understanding of the electronic structure of organic heterointerfaces both underpins this industry, and also presents us with a new landscape for discovery where we need to achieve a new level of control over molecular and nanoscale structure. Limitations in current device performance, for LEDs, PVs and FETs, are determined by limitations in our ability to control and measure structures at heterointerfaces. The vision of the present project is to achieve a step-change improvement in the control of molecular and nanoscale structure at organic heterointerfaces and thus to bring about a step-change in electronic functionality and performance of active semiconductor devices including LEDs, FETs and photovoltaics .The mining of this rich new seam of science will deliver game-changing discoveries for both science and engineering. The programme encompasses a variety of different interfaces, between organic-organic and organic-inorganic semiconductors; organic semiconductors and dielectrics; and organic semiconductor-electrode interfaces.

HIPERLAM is an SME driven Research and Innovation Action (RIA) well-aligned to the Factories of the Future (FoF) Initiative with a strong emphasis upon demonstrating superior cost and speed performance in end-to-end processes featuring laser-based additive manufacturing in two key applications requiring high resolution printed conductive metallic lines, namely laser printed RFID antenna and laser printed Fingerprint sensors. Existing subtractive top-down process will be replaced by HIPERLAM’s additive process for both Applications. Process maps illustrate the existing multiple processing steps compared to HIPERLAM’s significantly fewer steps. Real-time diagnostics are included and Modelling investigations will be undertaken to support optimisation. The promise of HIPERLAM’s high resolution laser based additive manufacturing solutions is to transform the manufacturing processing speed by 10x for laser printed RFID antenna (Application 1) and 5x in the case of the lead-time for laser printed fingerprint sensor design (Application 2). Similarly, HIPERLAM promises to reduce costs by 20x and 50% respectively for Application 1 and Application 2. HIPERLAM features high resolution LIFT Printing and Laser Sintering utilising novel high viscous inks to achieve printed conductive metallic structures down to 10 µm resolution over large areas (10 to 1000 cm2) suitable for scale-up to full production. The targeted applications address global market needs and will support mainstream adoption of AM processes in EU industry by displacing existing processes with smart, flexible, digitally enabled manufacturing technology. HIPERLAM business cases promise significant revenue growth in both application spaces and in the potential for consortium partners to establish themselves in pre-eminent positions in high resolution, low cost, high throughput AM technology.

INFINITY will develop an inorganic alternative to a scarce and high cost material, indium tin oxide (ITO), currently used as a Transparent Conductive Coating (TCC) for display electrodes on glass and plastic substrates. The novel conductive materials to be developed in this project will be based on low cost sol-gel chemistry using more widely available metallic elements and will leverage recent advances in nanostructured coatings. Novel printing procedures will also be developed to enable direct writing of multi and patterned nano-layers, removing the waste associated with etch patterning.