Nicholas J. Ekins-Daukes

Three-dimensional ToF-SIMS uncovers oxygen retention in the top Pt electrode and unexpected Pt migration into the oxide. This coupled exchange reshapes filament chemistry and may critically influence memristor reliability.

Oxide semiconductors have emerged as common channel materials in transistors and hold promise for next-generation electronics, yet achieving high mobility typically requires costly vacuum-based techniques. Here, ultrathin (5 nm) indium native oxide (InO_x) prepared by ambient-air liquid-metal printing (LMP) at a low temperature (250 °C) is applied as a semiconducting channel in a field-effect transistor (FET). The resulting InO_x is found to be polycrystalline, with large lateral grains that extend vertically throughout the film thickness. InO_x FETs in a transfer length method configuration demonstrate a high conductivity mobility (μ_CON) of 125 cm² V^–1 s^–1, with systematic analysis of contact resistance confirming the potential for channel length scaling. Integration with atomic-layer-deposited gate dielectrics further reveals excellent compatibility; for instance, an InO_x FET integrated with HfO₂ exhibits a high field-effect mobility (μ_FE) of 107 cm² V^–1 s^–1, an on/off current ratio (I_ON/I_OFF) of >10⁷, a subthreshold swing (SS) of 204 mV dec^–1, and a gate leakage of –6 A cm^–2, while maintaining stable performance over 10⁴ endurance cycles without degradation. Postfabrication oxygen plasma treatment is applied to achieve enhancement-mode operation, and a depletion-load inverter is demonstrated, exhibiting a voltage gain of 69.8 V/V. These results demonstrate the great potential of LMP InO_x as a semiconducting channel in high-performance and power-efficient transistors for next-generation oxide electronics.

Ambient-temperature thermal infrared radiation is an underutilised resource for secure communications. Demonstrations of free-space data transfer using thermal radiation have been few, and have relied on intrinsically slow modulation of either the emissivity and/or physical temperature of a broadband blackbody emitter, severely limiting data transfer rates ( < 1 kHz). Here, we demonstrate a covert communications method in which photon emission is rapidly electrically modulated both above and below the level of a passive blackbody at the emitter temperature. The time-averaged emission can be designed to be identical to the thermal background, realizing communications with zero optical signature for detectors with bandwidth lower than the modulation frequency. We demonstrate this scheme using both electro- and negative luminescence in thermoradiative diodes, enabling data rates up to at least 100 kbps and modulation rates above 1 MHz. Future prospects for ultra-high-bandwidth (up to THz) emitters and detectors utilising meta-optics and 2D materials are discussed.

Understanding how energy is transformed on ultrafast time scales is fundamental to the study of photophysics. Transient absorption spectroscopy is widely used to follow these processes, yet the usual "magic-angle" approach superimposes signals with differing polarization in the molecular frame. We employ a simple polarization-resolved method that separates parallel and perpendicular components of molecular-frame transient spectra, revealing otherwise obscured excited-state dynamics. Applied to two chromophore dimers capable of singlet fission, the analysis uncovers orthogonal electronic transitions and clarifies the coupling between monomer units. The molecular-frame spectra exhibit features masked by following the conventional approach, allowing extraction of triplet-pair formation dynamics. This accessible method provides richer insight into excited-state coupling and can be extended to a diverse range of photoactive materials.

Electrolyte-gated transistors (EGTs) are promising candidates for flexible neuromorphic electronics featuring low-voltage operation via ion-electron coupling. However, precise threshold control remains a key challenge due to the dynamic nature of the electric double layer (EDL). This study introduces a facile doping strategy, in which Na⁺ cations, analogous to biological neurotransmission ions, are incorporated into chitosan-based EGTs to modulate the EDL. This approach enables continuous threshold voltage tuning by controlling NaCl doping concentrations. At 0.5 wt %, a clear transition from depletion to enhancement mode is achieved with a Quasi-neutral turn-off condition, where the drain current without gate bias decreases from ∼10^-4 A (0 wt %) to below 10^-7 A (0.5 wt %) under 0.2 V drain voltage, and the energy consumption for synaptic functions is reduced by ∼200 times. The resulting devices exhibit high on/off ratios of >10³, operational stability exceeding 100 days, and excellent mechanical durability over 1000 bending cycles, making them suitable for flexible green bioelectronics. Furthermore, the devices can emulate key synaptic behaviors, including excitatory postsynaptic currents, paired-pulse facilitation, and spike-dependent plasticity, enabling neuromorphic computing with >95% accuracy in image recognition. This work establishes a scalable, biocompatible, and energy-efficient platform for threshold-controllable green EGTs in next-generation flexible neuromorphic devices.

Semi-transparent PV technologies demonstrated or proposed for agrivoltaics are reviewed and a new commercially viable concept to introduce spectral selectivity into semi-transparent c-Si modules is proposed.

Understanding how energy is transformed on ultrafast timescales is fundamental to the study of photophysics. Transient absorption spectroscopy is widely used to follow these processes, yet the usual 'magic-angle' approach superimposes signals with differing polarization in the molecular frame. We employ a simple polarization-resolved method that separates parallel and perpendicular components of molecular-frame transient spectra, revealing otherwise obscured excited-state dynamics. Applied to two chromophore dimers capable of singlet fission, the analysis uncovers orthogonal electronic transitions and clarifies the coupling between monomer units. The molecular-frame spectra exhibit features masked by following the conventional approach, allowing extraction of triplet-pair formation dynamics. This accessible method provides richer insight into excited-state coupling and can be extended to a diverse range of photoactive materials.

Every ten years the photovoltaic market grows tenfold, driven by increasing cell efficiencies and lower manufacturing and installation costs. If the next decade maintains this trend it must be via a technological transformation: The first commercial silicon-based devices that exceed the 29.4% efficiency limit of conventional ‘single junction’ silicon cells.Tandem cells are a contender to lead the transition. They complement the response of silicon in the near infrared with a second solar cell tuned for the visible spectrum. Tandem cells, however, have important constraints, typically including the need for current matching between two solar cells, more complex manufacturing requirements, and less consistent performance under varying environmental and illumination conditions. In fact, tandems are yet to be manufactured at scale or produce significant energy terrestrially.