Al_(2)O_(3) nanoparticles as surface modifier enables deposition of high quality perovskite films for ultra-flexible photovoltaics

Advanced photovoltaics,such as ultra-flexible perovskite solar cells(UF-PSCs),which are known for their lightweight design and high power-to-mass ratio,have been a long-standing goal that we,as humans,have continuously pursued.Unlike normal PSCs fabricated on rigid substrates,producing high-efficiency UF-PSCs remains a challenge due to the difficulty in achieving full coverage and minimizing defects of metal halide perovskite(MHP)films.In this study,we utilized Al_(2)O_(3) nanoparticles(NPs)as an inorganic surface modifier to enhance the wettability and reduce the roughness of poly-bis(4-phenyl)(2,4,6-trimethylphenyl)amine simultaneously.This approach proves essentials in fabricating UF-PSCs,enabling the deposition of uniform and dense MHP films with full coverage and fewer defects.We systematically investigated the effect of Al_(2)O_(3) NPs on film formation,combining simulation with experiments.Our strategy not only significantly increases the power conversion efficiency(PCE)from 11.96%to 16.33%,but also promotes reproducibility by effectively addressing the short circuit issue commonly encountered in UF-PSCs.Additionally,our UF-PSCs demonstrates good mechanical stability,maintaining 98.6%and 79.0%of their initial PCEs after 10,000 bending cycles with radii of 1.0 and 0.5 mm,respectively.

Ultra-flexible graphene/nylon/PDMS coaxial fiber-shaped multifunctional sensor

The development of flexible and wearable devices is mainly required for tactile sensing;as such devices can adapt to complicated nonuniform surfaces,they can be applied to the human body.Nevertheless,it remains necessary to simultaneously achieve small-scale,portable,and stable developments in such devices.Thus,this work aims at fabricating a novel,lightweight,ultra-flexible,and fiber-shaped coaxial structure with a diameter of 0.51 mm using polydimethylsiloxane/graphene/nylon material,based on piezoresistive and triboelectric principles.The piezoresistive-based robotic-hand-controlled sensor thus realized exhibits a response time of 120 ms and a fast recovery time of 55 ms.Further,the piezoresistive-based sensors effectively feature whisker/joystick-guided behaviors and also sense the human finger contact.Owing to the triboelectric-based selfpowered nanogenerator behavior,the resulting sensor can convert mechanical motion into electrical energy,without adversely affecting human organs.Moreover,this triboelectric-based human finger sensor can be operated under different bending modes at specific angles.Notably,this multifunctional sensor is cost-effective and suitable for various applications,including robotichand-controlled operations in medical surgery,whisker/joystick motions in lightweight drone technology,and navigation with highsensitivity components.

Freestanding and Ultra‑flexible PAN/ZIF‑67 Hybrid Membrane with Controlled Porosity for High‑Performance and High‑Safety Lithium Batteries Separator

Herein,a flexible ZIF-67/PAN hybrid membrane was successfully prepared by the incorporation of ZIF-67 nanoparticles and PAN nanofibers through electrospinning method.The hybrid membrane presented tomatoes on sticks structures with one single PAN fiber stringing series of ZIF-67 nanoparticles.The morphology,electrolyte wettability,heat resistance,flexibility,and electrochemical properties of the electrospun ZIF-67/PAN membranes were discussed.Among the membranes prepared with different percentage of ZIF-67,the 30% ZIF-67/PAN membrane exhibited outstanding heat shrinkage resistance(remained intact at 200℃ for 1 h),excellent electrolyte uptake(556.39%),wide electrochemical window(~5.25 V)and high ionic conductivity(2.98 mS cm^(−1)).When used as lithium-ion batteries(LIBs)separators,the cells assembled by 30% ZIF-67/PAN membrane presented excellent rate capacity and high capacity retention of 86.9% after 300 cycles at 1C.More importantly,the cells assembled with ZIF-67/PAN membranes repeated bent for 1000 times also exhibited high rate performance and maintained capacity retention of 92% after 100 cycles at 1 C.The characterization and the electrochemical testing suggest the electrospinning prepared ZIF-67/PAN flexible membranes can be expected to be used as potential separator for advanced batteries with high safety and high performance.