Mixed-dimensional stacked nanocomposite structures for a specific wavelength-selectable ambipolar photoresponse

Mixed-dimensional composite structures using zero-dimensional(0D)quantum dots(QDs)and two-dimensional(2D)transition metal dichalcogenides(TMDs)materials are expected to attract great interest in optoelectronics due to the potential to generate new optical properties.Here,we report on the unique optical characteristics of a devices with mixed dimensional vertically stacked structures based on tungsten diselenide(WSe_(2))/CdSeS QDs monolayer/molybdenum disulfide(MoS_(2))(2D/0D/2D).Specifically,it exhibits an ambipolar photoresponse characteristic,with a negative photoresponse observed in the 400-600 nm wavelength range and a positive photoresponse appeared at 700 nm wavelength.It resulted in the high negative responsivity of up to 52.22 mA·W^(−1)under 400 nm,which is 163 times higher than that of the photodetector without CdSeS QDs.We also demonstrated the negative photoresponse,which could be due to increased carrier collision probability and non-radiative recombination.Device modeling and simulation reveal that Auger recombination among the types of non-radiative recombination is the main cause of negative photocurrent generation.Consequently,we discovered ambipolar photoresponse near a specific wavelength corresponding to the energy of quantum dots.Our study revealed interesting phenomenon in the mixed low-dimensional stacked structure and paved the way to exploit it for the development of innovative photodetection materials as well as for optoelectronic applications.

Mixed-dimensional hierarchical configuration of 2D Ni_(2)P nanosheets anchored on 1D silk-derived carbon fiber for extraordinary electromagnetic wave absorption

Considering a series of electromagnetic pollution problems brought by the development of electronic communication technology,more attention has been paid to the research of electromagnetic wave(EMW)absorbing materials with unique composition and structure.Herein,under the inspiration of mixeddimensional hierarchical structure,2D Ni_(2)P nanosheets anchored on 1D silk-derived carbon fiber is successfully fabricated as a gratifying resistor-dielectric type absorber.By a controllable pyrolyzation strategy and disproportionated reaction,high-density 2D Ni_(2)P nanosheets were grown vertically and cross-linked on the surface of 1D silk-derived carbon fiber.The sample exhibited superior EMW absorption performance with maximum reflection loss value of–56.9 d B at the thickness of 2.32 mm and the effective absorption bandwidth can reach to 7.2 GHz at the thickness of 1.93 mm.In addition,the pure Ni_(2)P shows remarkable dielectric characteristic and EMW absorption ability as well.The integration of dualconductive loss,enhanced polarization relaxation loss and the multiple scattering in the composites was proved to contribute to the good EMW absorption performance.Therefore,this work confirms the great potentials of Ni_(2)P as a high-efficient EMW absorbing materials and light a new way in construction of multidimensional absorber.

Transition metal dichalcogenide-based mixed-dimensional heterostructures for visible-light-driven photocatalysis:Dimensionality and interface engineering

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)are emerging as promising building blocks of high-performance photocatalysts for visible-light-driven water splitting because of their unique physical,chemical,electronic,and optical properties.This review focuses on the fundamentals of 2D TMDC-based mixed-dimensional heterostructures and their unique properties as visible-light-driven photocatalysts from the perspective of dimensionality and interface engineering.First,we discuss the approaches and advantages of surface modification and functionalization of 2D TMDCs for photocatalytic water splitting under visible-light illumination.We then classify the strategies for improving the photocatalytic activity of 2D TMDCs via combination with various low-dimensional nanomaterials to form mixed-dimensional heterostructures.Further,we highlight recent advances in the use of these mixed-dimensional heterostructures as high-efficiency visible-light-driven photocatalysts,particularly focusing on synthesis routes,modification approaches,and physiochemical mechanisms for improving their photoactivity.Finally,we provide our perspectives on future opportunities and challenges in promoting real-world photocatalytic applications of 2D TMDC-based heterostructures.

Beyond two-dimension: One-and zero-dimensional halide perovskites as new-generation passivators for high-performance perovskite solar cells

Perovskite solar cells(PSCs) as a rising star in the photovoltaic field have received rapidly increasing attention recently due to the boosting power conversion efficiencies(PCEs) from 3.8% to 25.7% in the last13 years. Nevertheless, the conventional PSCs with three-dimensional(3D) halide perovskites as light absorbers suffer from inferior PCEs and poor durability under sunlight, high-temperature and humid conditions due to the high defect amount and structural instability of 3D perovskites, respectively. To tackle these crucial issues, lower-dimensional halide perovskites including zero-dimensional(0D), onedimensional(1D), and two-dimensional(2D) perovskites have been employed as efficient passivators to boost the PCEs and durability of 3D-PSCs due to the high structural stability and superior resistance against moisture, heat and sunlight. Therefore, in order to achieve better understanding about the advantages and superiorities of combining low-dimensional perovskites with their 3D counterparts in improving the PCEs and durability of 3D-PSCs, the recent advances in the development and fabrication of mixeddimensional PSCs with 1D/0D perovskites as passivators are summarized and discussed in the review.The superiority of 1D/0D perovskites as passivators over 2D counterparts, the passivation mechanism and the methods of 1D/0D perovskites are also presented and discussed. Furthermore, the rules to choose1D/0D perovskites or relevant spacer cations are also emphasized. On this basis, several specific strategies to design and fabricate mixed-dimensional PSCs with 1D/0D perovskites are presented and discussed.Finally, the crucial challenges and future research directions of mixed-dimensional PSCs with 1D/0D perovskites as passivators are also proposed and discussed. This review will provide some useful insights for the future development of high-efficiency and durable mixed-dimensional PSCs.

Constructing cactus-like mixed dimensional MOF@MOF as sorbent for extraction of bisphenols from environmental water

Metal-organic frameworks(MOFs)received considerable attention to adsorption and removal of various environmental pollutants because of some inherent advantages.However,it is challenging but meaningful to design and fabricate hierarchical mixed-dimensional MOFs with synergistic effects to enhance the performance for removal and preconcentration of environmental pollutants.Herein,a new hierarchical two-dimensional(2D)-three-dimensional(3D)mixed-dimensional cactus-like MOF@MOF hybrid material(PCN-134@Zr-BTB)was prepared by in-situ growth of 2D MOF nanosheets(Zr-BTB)on the surface of 3D MOF(PCN-134).The PCN-134@Zr-BTB composites combine the advantages of 2D and 3D MOFs with extensive mesoporous structures and large surface area for effective removal and enrichment of bisphenols(BPs).In comparison with pristine PCN-134 and Zr-BTB materials,the PCN-134@Zr-BTB hybrid material presented excellent adsorption performance for BPs.The adsorption isotherms are consistent with the Langmuir model,and the maximum adsorption capacity of four bisphenols(BPs)ranged from 135.1 mg/g to 628.9 mg/g.The adsorption kinetics are in accordance with the pseudo-second-order model.The recoveries ranged from 72.8%to 108%.The limits of detection were calculated at 0.02-0.03 ng/mL.The enrichment factors were calculated in the range of 310-374.According to FT-IR and XPS analysis,the main adsorption mechanisms are hydrogen bonding and π-π stacking.Nevertheless,this work provides a new and convenient strategy for the preparation of new hierarchical mixed-dimensional MOF@MOF(PCN-134@Zr-BTB)hybrid material for extraction and enrichment of BPs from aqueous matrix.