Weiyou

An all-optical neural stimulation strategy is demonstrated by utilizing spectrum-tunable NaYF4 based upconversion nanoparticles, which are used as transducers to absorb near-infrared energy and to emit visible light for stimulating neurons expressing channelrhodopsin proteins by Feng Wang, Peng Shi, and co-workers in article 1700446. Depending on the different dopants in the particles, the spectrum of their upconverted emission can be tuned to accommodate different opsin proteins for multiplexed and combinatorial neural stimulation, which is systematically characterized in cultured primary neurons as well as in rodent animals.

A new highly efficient near-infrared organic light-emitting material is reported by Zuo-Quan Jiang, Liang-Sheng Liao, and co-workers in article number 1700986. The donor-acceptor intramolecular interaction accounts for the near-infrared emission whereas the applied strong electron-withdrawing unit acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile is proposed for the first time. Under the mechanism of thermally activated delayed fluorescence, it exhibits over 10% external quantum efficiency with the peak of 693 nm.

Low-temperature solution processing opens a new window for the fabrication of oxide semiconductors due to its simple, low cost, and large-area uniformity. Herein, by using solution combustion synthesis (SCS), p-type Cu-doped NiO (Cu:NiO) thin films are fabricated at a temperature lower than 150 °C. The light doping of Cu substitutes the Ni site and disperses the valence band of the NiO matrix, leading to an enhanced p-type conductivity. Their integration into thin-film transistors (TFTs) demonstrates typical p-type semiconducting behavior. The optimized Cu_5%NiO TFT exhibits outstanding electrical performance with a hole mobility of 1.5 cm² V⁻¹ s⁻¹, a large on/off current ratio of ≈10⁴, and clear switching characteristics under dynamic measurements. The employment of a high-k ZrO₂ gate dielectric enables a low operating voltage (≤2 V) of the TFTs, which is critical for portable and battery-driven devices. The construction of a light-emitting-diode driving circuit demonstrates the high current control capability of the resultant TFTs. The achievement of the low-temperature-processed Cu:NiO thin films via SCS not only provides a feasible approach for low-cost flexible p-type oxide electronics but also represents a significant step toward the development of complementary metal–oxide semiconductor circuits.

A solution combustion synthesis is utilized to fabricate p-type oxide thin-film transistors (TFTs) at 150 °C. The doping of Cu into the NiO matrix can replace the Ni sites and enhance the p-type conductivity. The optimized Cu_5%NiO TFTs on both Si and ITO (indium tin oxide)/glass with ZrO₂ gate dielectrics exhibit an average hole mobility of >1 cm² V⁻¹ s⁻¹ and I_on/I_off of 10⁴.

Bicontinuous nanoporous N-doped graphene with tunable pore size is synthesized by nanoporous Ni-based chemical vapor deposition. The novel 3D graphene material shows an outstanding catalytic activity towards the oxygen reduction reaction with a low onset potential of −0.08 V and a high kinetic current density of 8.2 mA cm⁻² at −0.4 V.