FWF - NeuroImprint - Organic neuromorphic devices by 3D nanoimprinting “NeuroImprint”

Bioinspired neuromorphic devices have attracted considerable attention due to their potential applications in neuro-robotics or neuro-prosthetics. Organic materials devices are good candidates for such systems and could provide advantages of biocompatibility, low cost, low energy switching, low working voltage, excellent tunability and provide good mimic of the functions of biological synapses. Recently, bioinspired interactive neuromorphic devices with the ability to directly sense/store/process various stimuli from external environment have been realized by integrating sensors with synaptic devices on flexible substrates. The key remaining challenges for these systems include device reproducibility, limited performance and the absence of a fully scalable fabrication process. Based on large-area compatible direct 3D nanoimprinting processes, which we call “DINOFED”, we plan to fabricate innovative organic electrochemical transistors (OECTs), organic thin film transistors (OTFTs), and circuits based on these OECTs and OTFTs with minimized critical dimensions on a single substrate. Only one imprint step is needed to define high-resolution S/D patterns with small separation (< 1 µm) that are self-aligned to the highly crystalline organic semiconductor layer (OTFTs) or electroactive polymer (OECTs) resulting in organic transistors with a small channel length L and an ultraprecise definition of width W. The nanoimprinted OTFTs will be used to realize organic ring oscillators and organic rectifiers with high operation frequencies and reproducible characteristics. The proposed DINOFED process fulfills all requirements for the “next generation flexible electronics”, being large-area, parallel patterned with high throughput, high-resolution and inherently self-aligned. By integrating the nanoimprinted OECTs and organic circuits with tactile sensors on a single conformable substrate an artificial sensory neuron is realized and tested as neuromorphic learning device with the ability to “perceive” and “memorize” physical inputs. The proposed “DINOFED” process is a combination of hot embossing and micro-cutting. A 3D imprint tool defines a 3D-shaped pattern by a single imprint directly in a resist with a coated metal (Au) layer to define a high-resolution S/D pattern, µ-fluidic channels and predefined structures for the solution processed active layers. The organic semiconductors and gate dielectric layer are formed by blade-coating in the predefined structures and the defined electroactive polymer film is formed by self-wetting of the imprinted S/D pattern.