The fabrication of photoluminescent Ti C MXene quantum dots (MQDs) by a facile hydrothermal method is reported, which may greatly extend the applications of MXene-based materials. Interestingly, the as-prepared MQDs show excitation-dependent photoluminescence spectra with quantum yields of up to ≈10% due to strong quantum confinement. The applications of MQDs as biocompatible multicolor cellular imaging probes and zinc ion sensors are demonstrated.

Though polypyrrole (PPy) is widely used in flexible supercapacitors owing to its high electrochemical activity and intrinsic flexibility, limited capacitance and cycling stability of freestanding PPy films greatly reduce their practicality in real‐world applications. Herein, we report a new approach to enhance PPy's capacitance and cycling stability by forming a freestanding and conductive hybrid film through intercalating PPy into layered Ti3C2 (l‐Ti3C2, a MXene material). The capacitance increases from 150 (300) to 203 mF cm−2 (406 F cm−3). Moreover, almost 100% capacitance retention is achieved, even after 20 000 charging/discharging cycles. The analyses reveal that l‐Ti3C2 effectively prevents dense PPy stacking, benefiting the electrolyte infiltration. Furthermore, strong bonds, formed between the PPy backbones and surfaces of l‐Ti3C2, not only ensure good conductivity and provide precise pathways for charge‐carrier transport but also improve the structural stability of PPy backbones. The freestanding PPy/l‐Ti3C2 film is further used to fabricate an ultra‐thin all‐solid‐state supercapacitor, which shows an excellent capacitance (35 mF cm−2), stable performance at any bending state and during 10 000 charging/discharging cycles. This novel strategy provides a new way to design conductive polymer‐based freestanding flexible electrodes with greatly improved electrochemical performances.

Here, we report a facile method to delaminate MXene (Ti 3 C 2 T x ) and prepare poly(vinylidene fluoride) (PVDF)/MXene composites by solution blending. Compared with neat PVDF, the PVDF composites with varying content of MXene (0-5 wt%) showed an enhancement in the PVDF thermal conductivity. In particular, when a loading of 5 wt% was attained, the thermal conductivity was increased to 0.363 W mK À1 , an approximate 1-fold enhancement compared with that of neat PVDF. In addition, MXene also exhibited a better performance in enhancing the thermal dynamic mechanical properties of PVDF. For instance, PVDF composites with only 5 wt% MXene exhibited a storage modulus as high as 7501 MPa, corresponding to a 64% enhancement compared with that of neat PVDF. In light of the excellent thermal properties of the PVDF/MXene composites, they can be expected to have a wide range of potential applications in thermal interfacial materials and structural components.

Novel accordion structure Ti3C2–Ni0.5Zn0.5Fe2O4composites with nice electromagnetic wave absorption properties.