Natural musculoskeletal systems have been widely recognized as an advanced robotic model for designing robust yet flexible microbots. However, the development of artificial musculoskeletal systems at micro-nanoscale currently remains a big challenge, since it requires precise assembly of two or more materials of distinct properties into complex 3D micro/nanostructures. In this study, we report femtosecond laser programmed artificial musculoskeletal systems for prototyping 3D microbots, using relatively stiff SU-8 as the skeleton and pH-responsive protein (bovine serum albumin, BSA) as the smart muscle. To realize the programmable integration of the two materials into a 3D configuration, a successive on-chip two-photon polymerization (TPP) strategy that enables structuring two photosensitive materials sequentially within a predesigned configuration was proposed. As a proof-of-concept, we demonstrate a pH-responsive spider microbot and a 3D smart micro-gripper that enables controllable grabbing and releasing. Our strategy provides a universal protocol for directly printing 3D microbots composed of multiple materials.

A powerful sorbent of Li+, flower-like MoS2 nanocrystals, was doped into the Spiro-OMeTAD layer for highly efficient and stable perovskite solar cells.

The electron-transporting layer (ETL) plays a critical role in improving the charge extraction and suppressing the carrier recombination in planar perovskite solar cells (PSCs). Compact titanium dioxide (TiO 2 ) film is a widely used as an ETL in conventional n-i-p PSCs. However, there is still much room for improvement in the electron mobility and reducing the oxygen vacancies of the compact TiO 2 film. Herein, Pt-doped TiO 2 film with outstanding electron-transporting property and complete coverage on the substrates is reported by the authors. Pt-doping results in a tailed band level of TiO 2 , which could suppress the charge accumulation at the interface of TiO 2 -Pt/perovskite. Consequently, TiO 2 -Pt ETL based PSCs deliver a power conversion efficiency as high as 20.05% with an open-circuit voltage of 1.15 V, a fill factor of 0.75, a short-circuit current density of 23.83 mA cm À2 and remarkably alleviated hysteresis behavior.

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