ZIF-67 Derivative Decorated MXene for a Highly Integrated Flexible Self-Powered Photodetector

High-Performance Self-Powered Photodetector Enabled by Te-Doped GeH Nanostructures Engineering

Two-dimensional (2D) Xenes, including graphene where X represents C, Si, Ge, and Te, represent a groundbreaking class of materials renowned for their extraordinary electrical transport properties, robust photoresponse, and Quantum Spin Hall effects. With the growing interest in 2D materials, research on germanene-based systems remains relatively underexplored despite their potential for tailored optoelectronic functionalities. Herein, we demonstrate a facile and rapid chemical synthesis of tellurium-doped germanene hydride (Te-GeH) nanostructures (NSs), achieving precise atomic-scale control. The 2D Te-GeH NSs exhibit a broadband optical absorption spanning ultraviolet (UV) to visible light (VIS), which is a critical feature for multifunctional photodetection. Leveraging this property, we engineer photoelectrochemical (PEC) photodetectors via a simple drop-casting technique. The devices deliver excellent performance, including a high responsivity of 708.5 µA/W, ultrafast response speeds (92 ms rise, 526 ms decay), and a wide operational bandwidth. Remarkably, the detectors operate efficiently at zero-bias voltage, outperforming most existing 2D-material-based PEC systems, and function as self-powered broadband photodetectors. This work not only advances the understanding of germanene derivatives but also unlocks their potential for next-generation optoelectronics, such as energy-efficient sensors and adaptive optical networks.

MXenes for Bioinspired Soft Actuators: Advancements in Angle-Independent Structural Colors and Beyond

Soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics, biomedical devices, and biomimetic systems. These actuators mimic the natural movements of living organisms, aiming to attain  enhanced flexibility, adaptability, and versatility. On the other hand, angle-independent structural color has been achieved through innovative design strategies and engineering approaches. By carefully controlling the size, shape, and arrangement of nanostructures, researchers have been able to create materials exhibiting consistent colors regardless of the viewing angle. One promising class of materials that holds great potential for bioinspired soft actuators is MXenes in view of their exceptional mechanical, electrical, and optical properties. The integration of MXenes for bioinspired soft actuators with angle-independent structural color offers exciting possibilities. Overcoming material compatibility issues, improving color reproducibility, scalability, durability, power supply efficiency, and cost-effectiveness will play vital roles in advancing these technologies. This perspective appraises the development of bioinspired MXene-centered soft actuators with angle-independent structural color in soft robotics.

A self-sacrificing template strategy: In-situ construction of bimetallic MOF-derived self-supported CuCoSe nanosheet arrays for high-performance supercapacitors

Transition metal selenides (TMSs) are viewed as a prospective high-capacity electrode material for asymmetric supercapacitors (ASCs). However, the inability to expose sufficient active sites due to the limitation of the area involved in the electrochemical reaction severely limits their inherent supercapacitive properties. Herein, a self-sacrificing template strategy is developed to prepare self-supported CuCoSe (CuCoSe@rGO-NF) nanosheet arrays by in situ construction of copper-cobalt bimetallic organic framework (CuCo-MOF) on rGO-modified nickel foam (rGO-NF) and rational design of Se2- exchange process. Nanosheet arrays with high specific surface area are considered to be ideal platforms for accelerating electrolyte penetration and exposing rich electrochemical active sites. As a result, the CuCoSe@rGO-NF electrode delivers a high specific capacitance of 1521.6 F/g at 1 A/g, good rate performance and an excellent capacitance retention of 99.5% after 6000 cycles. The assembled ASC device has a high energy density of 19.8 Wh kg-1 at 750 W kg-1 and an ideal capacitance retention of 86.2% after 6000 cycles. This proposed strategy offers a viable strategy for designing and constructing electrode materials with superior energy storage performance.

Chloroplast-Inspired Carrier Circulation for Improved Photoelectrochemical Photodetectors Based on Ti2CTx Nanosheets

Here, a photoelectrochemical (PEC) photodetector with good flexibility and high photoresponsivity was successfully fabricated in a vertical structure, where the MXene (Ti2CTx) nanosheet and carbon black electrode were separated by adenosine triphosphate/nicotinamide adenine dinucleotide phosphate (ATP/NADPH)-incorporated solid-state electrolyte. The photocurrent and photoresponsivity can reach 1.84 μA/cm2 and 8.89 μA/W, respectively, under a light intensity of 90 mW/cm2 at a bias potential of 0.6 V, which are approximately 2.3 times those of Ti2CTx nanosheets. The addition of ATP and NADPH to the electrolyte also leads to a large decrease of the rise time from 0.76 to 0.26 s. Furthermore, the photodetector can continue to function and maintain stability under 45° bending and after 500 cycles of bending, indicating a robust device structure and great flexibility. The performance enhancement of the PEC photodetector can be attributed to the synergistic effect of electrolyte additives on Ti2CTx nanosheets, where ATP and NADPH greatly enhance the circulation and utilization of photogenerated carriers. This work suggests that the incorporation of chloroplast-inspired carrier circulation with two-dimensional nanosheets could achieve efficient light-current conversion, providing a new strategy to improve the performance of PEC-type photodetectors.

Progress and challenges of emerging MXene based materials for thermoelectric applications

To realize sustainable development, more and more countries forwarded carbon neutrality goal. Accordingly, improving the utilization efficiency of traditional fossil fuel is an effective strategy for this great goal. Keeping this in mind, developing thermoelectric devices to recover waste heat energy resulted in the consumption process of fuel is demonstrated to be promising. High performance thermoelectric devices require advanced materials. MXenes are a kind of 2D materials with a layered structure, which demonstrate excellent thermoelectric performance owing to their unique physical, mechanical, and chemical properties. Also, substantial achievement has been gained during the past few years in synthesizing MXene based materials for thermoelectric devices. In this review, the mainstream synthetic routes of MXene from etching MAX were summarized. Significantly, the current state and challenges of research on improving the performance of MXene based thermoelectrics are explored, including pristine MXene and MXene based composites.

Advances in the Field of Two-Dimensional Crystal-Based Photodetectors

Two-dimensional (2D) materials have sparked intense interest among the scientific community owing to their extraordinary mechanical, optical, electronic, and thermal properties. In particular, the outstanding electronic and optical properties of 2D materials make them show great application potential in high-performance photodetectors (PDs), which can be applied in many fields such as high-frequency communication, novel biomedical imaging, national security, and so on. Here, the recent research progress of PDs based on 2D materials including graphene, transition metal carbides, transition-metal dichalcogenides, black phosphorus, and hexagonal boron nitride is comprehensively and systematically reviewed. First, the primary detection mechanism of 2D material-based PDs is introduced. Second, the structure and optical properties of 2D materials, as well as their applications in PDs, are heavily discussed. Finally, the opportunities and challenges of 2D material-based PDs are summarized and prospected. This review will provide a reference for the further application of 2D crystal-based PDs.

Fast and High-Performance Self-Powered Photodetector Based on the ZnO/Metal-Organic Framework Heterojunction

Electrical conductive metal-organic frameworks (EC-MOFs) are emerging as an appealing class of highly tailorable electrically conducting materials with potential applications in optoelectronics. Here, we in situ grew nickel hexahydroxytriphenylene (Ni-CAT) on the surface of ZnO nanorods (NRs). The self-powered photodetectors (PDs) were fabricated with heterojunctions formed at the interface of ZnO NRs and Ni-CAT. With this, the built-in electric field (BEF) can effectively separate the photogenerated electron-hole pairs and enhance the photoresponse. We observe that the PDs based on hybrid ZnO/Ni-CAT with 3 h of growth time (ZnO/Ni-CAT-3) show good photoresponse (137 μA/W) with the fast rise (3 ms) and decay time (50 ms) under 450 nm light illumination without biased voltage. This work provides a facile and controllable method for the growth of the ZnO/Ni-CAT heterojunction with an effective BEF zone, which will benefit their optoelectronic applications.