Two-dimensional (2D) material-based hydrogels have been widely utilized as the ink for extrusion-based 3D printing in various electronics. However, the viscosity of the hydrogel ink is not high enough to maintain the self-supported structure without architectural deformation. It is also difficult to tune the microstructure of the printed devices using a low-viscosity hydrogel ink. Herein, by mimicking a phospholipid bilayer in a cytomembrane, the amphiphilic surfactant nonaethylene glycol monododecyl ether (C12E9) was incorporated into MXene hydrogel. The incorporation of C12E9 offers amphiphilicity to the MXene flakes and produces a 3D interlinked network of the MXene flakes. The 3D interlinked network offers a high-viscosity, homogenized flake distribution and enhanced printability to the ink. This ink facilitates the alignment of the MXene flakes during extrusion as well as the formation of the aligned micro- and sub-microsized porous structures, leading to the improved electrochemical performance of the printed microsupercapacitor. This study provides an example for the preparation of microelectronics with tunable microstructures.

Sb2S3 is an attractive solar absorber material that has garnered tremendous interest because of its fascinating properties for solar cells including suitable band gap, high absorption coefficient, earth abundance, and excellent stability. Over the past several years, intensive efforts have been made to enhance the photovoltaic efficiencies of Sb2S3 solar cells using many promising approaches including interfacial engineering, surface passivation, additive engineering, and band‐gap engineering of the charge transport layers and active light absorbing Sb2S3 materials. Recently, doping strategies in Sb2S3 light absorbers have gained attention as they promise to play important roles in controlling band gap, regulating film morphology, and passivating grain boundaries, and thus resulting in enhanced carrier transport, which is one of the most challenging issues in this cutting‐edge research field. In this review, after a brief introduction to Sb2S3, an overview of Sb2S3 solar cells and their fundamental properties are provided. Recent advances in doping strategies in Sb2S3 thin films and solar cells are then discussed to provide in‐depth understanding of the effects of various dopants on the photovoltaic properties of Sb2S3 materials. In conclusion, the personal perspectives and outlook to the future development of Sb2S3 solar cells are provided.

Three‐dimensional (3D) printing has gained popularity in a variety of applications, particularly in the manufacture of wearable devices. Aided by the large degree of freedom in customizable fabrication, 3D printing can cater towards the practical requirements of wearable devices in terms of light weight and flexibility. In particular, this focus review aims to cover the important aspect of wearable energy storage devices (WESDs), which is an essential component of most wearable devices. Herein, the topics discussed are the fundamentals of 3D printing inks used, the optimizing strategies in improving the mechanical and electrochemical properties of wearable devices and the recent developments and challenges of wearable electrochemical systems such as batteries and supercapacitors. It can be expected that, with the development of 3D printing technology, realization of the full potential of WESDs and seamless integration into smart devices also needs further in‐depth investigations.