A step‐by‐step strategy is reported for improving capacitance of supercapacitor electrodes by synthesizing nitrogen‐doped 2D Ti2CTx induced by polymeric carbon nitride (p‐C3N4), which simultaneously acts as a nitrogen source and intercalant. The NH2CN (cyanamide) can form p‐C3N4 on the surface of Ti2CTx nanosheets by a condensation reaction at 500–700 °C. The p‐C3N4 and Ti2CTx complexes are then heat‐treated to obtain nitrogen‐doped Ti2CTx nanosheets. The triazine‐based p‐C3N4 decomposes above 700 °C; thus, the nitrogen species can be surely doped into the internal carbon layer and/or defect site of Ti2CTx nanosheets at 900 °C. The extended interlayer distance and c‐lattice parameters (c‐LPs of 28.66 Å) of Ti2CTx prove that the p‐C3N4 grown between layers delaminate the nanosheets of Ti2CTx during the doping process. Moreover, 15.48% nitrogen doping in Ti2CTx improves the electrochemical performance and energy storage ability. Due to the synergetic effect of delaminated structures and heteroatom compositions, N‐doped Ti2CTx shows excellent characteristics as an electrochemical capacitor electrode, such as perfectly rectangular cyclic voltammetry results (CVs, R2 = 0.9999), high capacitance (327 F g−1 at 1 A g−1, increased by ≈140% over pristine‐Ti2CTx), and stable long cyclic performance (96.2% capacitance retention after 5000 cycles) at high current density (5 A g−1).

A facile methodology for the large-scale production of layer-controlled MoS layers on an inexpensive substrate involving a simple coating of single source precursor with subsequent roll-to-roll-based thermal decomposition is developed. The resulting 50 cm long MoS layers synthesized on Ni foils possess excellent long-range uniformity and optimum stoichiometry. Moreover, this methodology is promising because it enables simple control of the number of MoS layers by simply adjusting the concentration of (NH ) MoS . Additionally, the capability of the MoS for practical applications in electronic/optoelectronic devices and catalysts for hydrogen evolution reaction is verified. The MoS -based field effect transistors exhibit unipolar n-channel transistor behavior with electron mobility of 0.6 cm V s and an on-off ratio of ≈10³. The MoS -based visible-light photodetectors are fabricated in order to evaluate their photoelectrical properties, obtaining an 100% yield for active devices with significant photocurrents and extracted photoresponsivity of ≈22 mA W . Moreover, the MoS layers on Ni foils exhibit applicable catalytic activity with observed overpotential of ≈165 mV and a Tafel slope of 133 mV dec . Based on these results, it is envisaged that the cost-effective methodology will trigger actual industrial applications, as well as novel research related to 2D semiconductor-based multifaceted applications.

New fiber-type piezoelectric nanogenerator devices consisting of radially aligned perovskite PbTiO nanotubes are designed for energy harvesting from arbitrary mechanical motion. The free-standing fiber-type nanogenerators generate constant amount of electric power by bending or wind motion regardless of direction, thus, extending the possibility of their practical applications.

Complementary combination of heterostructures is a crucial factor for the development of 2D materials-based optoelectronic devices. Herein, an appropriate solution for fabricating complementary dimensional-hybrid nanostructures comprising structurally tailored ZnO nanostructures and 2D materials such as graphene and MoS is suggested. Structural features of ZnO nanostructures hydrothermally grown on graphene and MoS are deliberately manipulated by adjusting the pH value of the growing solution, which will result in the formation of ZnO nanowires, nanostars, and nanoflowers. The detailed growth mechanism is further explored for the structurally tailored ZnO nanostructures on the 2D materials. Furthermore, a UV photodetector based on the dimensional-hybrid nanostructures is fabricated, which demonstrates their excellent photocurrent and mechanical durability. This can be understood by the existence of oxygen vacancies and oxygen-vacancies-induced band narrowing in the ZnO nanostructures, which is a decisive factor for determining their photoelectrical properties in the hybrid system.

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Perhydropolysilazane (PHPS), an inorganic polymer composed of Si–N and Si–H, has attracted much attention as a precursor for gate dielectrics of thin-film transistors (TFTs) due to its facile processing even at a relatively low temperature. However, an in-depth understanding of the tunable dielectric behavior of PHPS-derived dielectrics and their effects on TFT device performance is still lacking. In this study, the PHPS-derived dielectric films formed at different annealing temperatures have been used as the gate dielectric layer for solution-processed indium zinc oxide (IZO) TFTs. Notably, the IZO TFTs fabricated on PHPS annealed at 350 °C exhibit mobility as high as 118 cm2 V–1 s–1, which is about 50 times the IZO TFTs made on typical SiO2 dielectrics. The outstanding electrical performance is possible because of the exceptional capacitance of PHPS-derived dielectric caused by the limited hydrolysis reaction of PHPS at a low processing temperature (<400 °C). According to our analysis, the exceptional dielectric behavior is originated from the electric double layer formed by mobile of protons in the low temperature-annealed PHPS dielectrics. Furthermore, proton conduction through the PHPS dielectric occurs through a three-dimensional pathway by a hopping mechanism, which allows uniform polarization of the dielectric even at room temperature, leading to amplified performance of the IZO TFTs.

Highly gas-sensitive organic transistors with MC have been demonstrated due to more grain boundaries and field-induced dipole aligning of MC.