Solid-state organic electrochemical transistors.

Organic electrochemical transistors (OECTs) continue to be the subject of much detailed and systematic study, being suitable for a diverse range of applications including bioelectronics, sensors, and neuromorphic computing. OECTs conventionally use a liquid electrolyte, and this architecture is well suited for sensing or bio-interfacing applications where biofluids or liquid samples can be used directly as the electrolyte. A more recent trend is solid-state OECTs, where a solid or semi-solid electrolyte such as an ion gel, hydrogel or polyelectrolyte replaces the liquid component for an all-solid-state device.

Flexible Ink-Jet Printed Polymer Light-Emitting Diodes using a Self-Hosted Non-Conjugated TADF Polymer.

Thermally activated delayed fluorescent (TADF) emitters have become the leading emissive materials for highly efficient organic light-emitting diodes (OLEDs). The deposition of these materials in scalable and cost-effective ways is paramount when looking toward the future of OLED applications. Herein, a simple OLED with fully solution-processed organic layers is introduced, where the TADF emissive layer is ink-jet printed.

Insight into OTFT Sensors Using Confocal Fluorescence Microscopy.

Confocal fluorescence microscopy provides a means to map charge carrier density within the semiconductor layer in an active organic thin film transistor (OTFT). This method exploits the inverse relationship between charge carrier density and photoluminescence (PL) intensity in OTFTs, originating from exciton quenching following exciton-charge energy transfer. This work demonstrates that confocal microscopy can be a simple yet effective approach to gain insight into doping and de-doping processes in OTFT sensors.

Biowaste-Derived, Self-Organized Arrays of High-Performance 2D Carbon Emitters for Organic Light-Emitting Diodes.

Low-cost flexible organic light-emitting diodes (OLEDs) with nanoemitter material from waste open up new opportunities for sustainable technology. The common emitter materials generated from waste are carbon dots (CDs). However, these have poor luminescent properties.

Spectral changes associated with transmission of OLED emission through human skin.

A recent and emerging application of organic light emitting diodes (OLEDs) is in wearable technologies as they are flexible, stretchable and have uniform illumination over a large area. In such applications, transmission of OLED emission through skin is an important part and therefore, understanding spectral changes associated with transmission of OLED emission through human skin is crucial. Here, we report results on transmission of OLED emission through human skin samples for yellow and red emitting OLEDs.

Direct-write crosslinking in vacuum-deposited small-molecule films using focussed ion and electron beams.

Recent advances in helium ion microscopy (HIM) have enabled the use of fine-focused He beams to image and shape materials at the nanoscale. In addition to traditional ion milling, the beam can also be used to induce reactions, such as cross-linking, in films of organic molecules. Here, we compare the use of focused ion and electron beams to fabricate spatially-defined cross-linked features in nanometre-thick films of tetracene.

A highly porous and conductive composite gate electrode for OTFT sensors.

Ionic/protonic to electronic transducers based on organic thin film transistors have shown great promise for applications in bioelectronic interface devices and biosensors, and development of materials that exhibit mixed ionic/electronic conduction are an essential part of these devices. In this work, we investigated the proton sensing properties of an all solid-state and low voltage operating organic thin film transistor (OTFT) that uses the organic mixed conductor poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) as the gate electrode. To address the limited sensitivity due to the lack of porosity in PEDOT:PSS base sensors, we proposed a composite gate electrode material composed of PEDOT:PSS and proton conducting mesoporous SOH-Si-MCM-41 nanoparticles for improved proton sensitivity.

Vinylene and benzo[][1,2,5]thiadiazole: effect of the π-spacer unit on the properties of bis(2-oxoindolin-3-ylidene)-benzodifuran-dione containing polymers for n-channel organic field-effect transistors.

Two polymers based on (3,7)-3,7-bis(2-oxoindolin-3-ylidene)benzo[1,2-:4,5-']difuran-2,6(3,7)-dione (BIBDF) coupled with ()-2-(2-(thiophen-2-yl)vinyl)thiophene (TVT) or dithienylbenzothiadiazole (TBT), namely PBIBDF-TVT and PBIBDF-TBT were synthesized the Stille coupling reaction. The effect of benzothiadiazole or vinylene-π spacer of the copolymers on optical properties, energy levels, electronic device performance and microstructure were studied. It was found that PBIBDF-TBT based OFET devices, annealed at 180 °C, showed better performance with the highest electron mobility of 2.

Effect of thermal annealing Super Yellow emissive layer on efficiency of OLEDs.

Thermal annealing of the emissive layer of an organic light emitting diode (OLED) is a common practice for solution processable emissive layers and reported annealing temperatures varies across a wide range of temperatures. We have investigated the influence of thermal annealing of the emissive layer at different temperatures on the performance of OLEDs. Solution processed polymer Super Yellow emissive layers were annealed at different temperatures and their performances were compared against OLEDs with a non-annealed emissive layer.

Planar silver nanowire, carbon nanotube and PEDOT:PSS nanocomposite transparent electrodes.

Highly conductive, transparent and flexible planar electrodes were fabricated using interwoven silver nanowires and single-walled carbon nanotubes (AgNW:SWCNT) in a PEDOT:PSS matrix via an epoxy transfer method from a silicon template. The planar electrodes achieved a sheet resistance of 6.6 ± 0.

Defining the light emitting area for displays in the unipolar regime of highly efficient light emitting transistors.

Light-emitting field effect transistors (LEFETs) are an emerging class of multifunctional optoelectronic devices. It combines the light emitting function of an OLED with the switching function of a transistor in a single device architecture. The dual functionality of LEFETs has the potential applications in active matrix displays.