Ti3C2T x MXene as a representative material in the emerging two-dimensional (2D) MXene family with high conductivity, abundant functional surface terminals, and large layer spacing is supposed to show specific semiconducting properties like other 2D graphene or transition metal dichalcogenides, thus extending Moore's law beyond silicon. However, despite extensive efforts, the design of Ti3C2T x MXene based semiconductor materials often depends on the availability of traditional semiconductors to form heterojunctions, where Ti3C2T x MXene is still in metallic characters and is not in dominant status in the heterojunctions. Here, we demonstrate semiconducting Ti3C2T x MXene modified with dodecyl (−C12H26) groups, as functionalized Ti3C2T x MXene possesses opened and typical layer-dependent bandgap. The new arising characteristics, red-shift of characteristic peaks, and intensity ratio of the A1g(C)/A1g(Ti, C, T x) in Raman spectroscopy suggested the successful grafting of the −C12H26 groups on the Ti3C2T x MXenes. In addition, the theoretical calculations by density functional theory, photoluminescence spectrum, together with photoelectric measurements of Ti3C2T x-C12H26 MXene on different layers, show a tunable bandgap of 0.49–2.15 eV and superior photoresponse properties in fabricating near infrared photodetectors.

Stimulus-responsive proton conduction materials have attracted enormous interest as a new kind of “smart material”. It is desirable to develop the appropriate stimulus signal and high proton-conducting materials with an excellent proton-conducting switch ratio (γ), but it remains a great challenge. Here, it can be found for the first time that 4-((2-hydroxybenzylidene)amino)benzenesulfonic acid (HBABSA) has obvious thermal isomerization when porous solids act as matrixes at the ambient temperatures, which is different from that in the crystalline state at 77 K. Therefore, we proposed a host–guest metal–organic framework (MOF) composite, namely, MOF-808 incorporated with HBABSA (HBABSA@MOF-808), which has a proton-conducting switch ratio (γ) of 16 between 338 and 343 K due to the thermally induced isomerization of HBABSA molecules in the MOF pores. The strong binding between the keto-type HBABSA and MOF at the relatively low temperatures can efficiently suppress the proton conduction, while the enol-type one provides more mobile protons for conduction at the high temperatures due to the excited-state intramolecular proton transfer mechanism. Further, the HBABSA@MOF-808 as a filler is blended into polyvinyl alcohol and poly(2-acrylamide-2-methyl-1-propane sulfonic acid) to form hybrid membranes. The hybrid membrane with the highest content of the MOF composite displays a high proton conductivity of 5.57 × 10–3 S·cm–1 under 353 K and 57% RH along with a good switch ratio of 5.4. The development of thermal-response proton-conducting MOF materials is opening up a unique pathway for remote control, thermal sensing, intelligent batteries, and other fields.

With the development of individual wearable electronics, the requirements of self‐energy harvest devices from human skin or motion have increased. A thermal harvest device that receives thermal energy naturally existed in human skin is more attractive than a mechanical energy harvester that needs human motion or walking. Herein, a thermal‐chargeable supercapacitor (TCSC) is proposed, which can convert thermal energy into electrical energy and then store the energy only by occurring the temperature difference between the two ends of the TCSC. The all‐solid‐state g‐C3N4‐modified hydrogel electrolyte in the TCSC provides more free protons and energy for proton migration by the electrostatic interaction and hydrogen bond interaction between g‐C3N4 and the acid group. The 2D MOF@Ti3C2Tx MXene heterojunction electrodes with the advantages of large pore size, adjustable and abundant REDOX sites of MOFs, and high conductivity of Ti3C2Tx MXene also ensure the high performance of the TCSC. As a result, the assembled TCSC exhibits excellent ionic thermal‐voltage (55.68 mV), Seebeck coefficient (18.56 mV K−1), and energy exchange efficiency (3.4%) upon a temperature difference of 3 K, and successfully drives the pressure sensor work.