For microelectronic devices, the on-chip microsupercapacitors with facile construction and high performance, are attracting researchers’ prior consideration due to their high compatibility with modern microsystems. Herein, we proposed interchanging interdigital Au-/MnO₂/polyethylene dioxythiophene stacked microsupercapacitor based on a microfabrication process followed by successive electrochemical deposition. The stacked configuration of two pseudocapacitive active microelectrodes meritoriously leads to an enhanced contact area between MnO₂ and the conductive and electroactive layer of polyethylene dioxythiophene, hence providing excellent electron transport and diffusion pathways of electrolyte ions, resulting in increased pseudocapacitance of MnO₂ and polyethylene dioxythiophene. The stacked quasi-solid-state microsupercapacitors delivered the maximum specific capacitance of 43 mF cm⁻² (211.9 F cm⁻³), an energy density of 3.8 μWh cm⁻² (at a voltage window of 0.8 V) and 5.1 μWh cm⁻² (at a voltage window of 1.0 V) with excellent rate capability (96.6% at 2 mA cm⁻²) and cycling performance of 85.3% retention of initial capacitance after 10000 consecutive cycles at a current density of 5 mA cm⁻², higher than those of ever reported polyethylene dioxythiophene and MnO₂-based planar microsupercapacitors. Benefiting from the favorable morphology, bilayer microsupercapacitor is utilized as a flexible humidity sensor with a response/relaxation time superior to those of some commercially available integrated microsensors. This strategy will be of significance in developing high-performance on-chip integrated microsupercapacitors/microsensors at low cost and environment-friendly routes.

The development of an efficient Pt-based electrocatalyst in acidic and alkaline electrolytes is of great significance to the field of electrocatalytic hydrogen evolution. Herein, we report a strategy for in situ growth of Pt₃Ni truncated octahedrons on Ti₃C₂T_x nanosheets and then obtain an ordered porous catalyst via a template method. Meanwhile, we use the finite element calculation to clarify the relationship between the component structure and performance and find that the performance of the spherical shell microstructure catalyst is higher than that of the disc structure catalyst, which is also verified by experiments. The experimental analysis shows that the ordered porous catalyst is conducive to enhancing electrocatalytic hydrogen evolution activity in acidic and alkaline electrolytes. In an acidic solution, the overpotential is 25 mV (10 mA·cm⁻²), and the Tafel slope is 22.86 mV·dec⁻¹. In an alkaline solution, the overpotential is 44.1 mV (10 mA·cm⁻²), and the Tafel slope is 39.06 mV·dec⁻¹. The synergistic coupling between Ti₃C₂T_x and Pt₃Ni nanoparticles improves the stability of the catalyst. The in situ growth strategy and design of microstructure with its correlation with catalytic performance represent critical steps toward the rational synthesis of catalysts with excellent catalytic activity.

Perovskite materials are promising candidates for the next generation of wearable optoelectronics. However, due to uncontrolled crystallization and the natural brittle property of crystals, it remains a great challenge to fabricate large-scale compact and tough perovskite film. Here we report a facile method to print large-scale perovskite films with high quality for flexible photodetectors. By introducing a soluble polyethylene oxide (PEO) layer during the inkjet printing process, the nucleation and crystal growth of perovskite is well controlled. Perovskite films can be easily printed in large scale and patterned in high resolution. Moreover, this method can be extended to various kinds of perovskite materials, such as MAPbI₃ (MA = methylammonium), MA₃Sb₂I₉, and (BA)₂PbBr₄ (BA = benzylammonium). The printed perovskite films show high quality and excellent mechanical performance. The photodetectors based on the MAPbBr₃ perovskite films show a responsivity up to ~ 1, 036 mA/W and maintain over 96.8% of the initial photocurrent after 15, 000 consecutive bending cycles. This strategy provides a facile approach to prepare large-scale flexible perovskite films. It opens up new opportunities for the fabrication of diverse wearable optoelectronic devices.