Machine Learning Accelerated Discovery of Functional MXenes with Giant Piezoelectric Coefficients

Recent advances in MXene-based composites for piezoelectric sensors

Piezoelectric sensors are crucial in medical, industrial, and consumer electronics applications, yet their performance and sensitivity often fall short due to the limitations in current piezoelectric materials. To address these deficiencies, significant research has been directed towards developing composite materials that enhance piezoelectric properties by integrating piezoelectric materials with various fillers. MXenes, a novel class of 2D transition metal carbides/nitrides, exhibit remarkable properties such as high electrical conductivity, mechanical strength, and chemical stability. These characteristics, along with a high surface area and hydrophilicity, make MXenes an ideal additive for preparing piezoelectric composites with improved properties. Despite existing reviews on MXenes in sensor applications, only a few have systematically explored their role in piezoelectric sensors. This review provides a comprehensive analysis of MXene-based piezoelectric sensors, examining the impact of different composites on piezoelectric properties, synthesis methods, structural designs, and application areas. While promising, challenges such as scalability, reproducibility, and environmental stability must be addressed to fully realize the potential of MXene-based composites. This comprehensive analysis highlights the advancements, opportunities for further development, and the transformative potential of MXenes in the next generation of high-performance, multifunctional piezoelectric sensors.

MXenes and artificial intelligence: fostering advancements in synthesis techniques and breakthroughs in applications

This review explores the synergistic relationship between MXenes and artificial intelligence (AI), highlighting recent advancements in predicting and optimizing the properties, synthesis routes, and diverse applications of MXenes and their composites. MXenes possess fascinating characteristics that position them as promising candidates for a variety of technological applications, including energy storage, sensors/detectors, actuators, catalysis, and neuromorphic systems. The integration of AI methodologies provides a robust toolkit to tackle the complexities inherent in MXene research, facilitating property predictions and innovative applications. We discuss the challenges associated with the predictive capabilities for novel properties of MXenes and emphasize the necessity for sophisticated AI models to unravel the intricate relationships between structural features and material behaviors. Moreover, we examine the optimization of synthesis routes for MXenes through AI-driven approaches, underscoring the potential for streamlining and enhancing synthesis processes via data-driven insights. Furthermore, the role of AI is elucidated in enabling targeted applications of MXenes across multiple domains, illustrating the correlations between MXene properties and application performance. The synergistic integration of MXenes and AI marks the dawn of a new era in material design and innovation, with profound implications for advancing diverse technological frontiers.

Giant In-Plane Flexoelectricity and Radial Polarization in Janus IV-VI Monolayers and Nanotubes

Nanotubes have established a new paradigm in nanoscience because of their atomically thin geometries and intriguing properties. However, because of their typical metastability compared to their 2D and 3D counterparts, it is still fundamentally challenging to synthesize nanotubes with controlled size. New strategies have been suggested for synthesizing nanotubes with a controlled geometry. One of these is considering Janus 2D layers, which can self-roll to form a nanotube. Herein, we study 412 nanotubes (along the armchair and zigzag directions) based on 36 Janus IV-VI compounds using density functional theory (DFT) calculations. By investigating the energy-radius relationship using structural models and Bayesian predictions, the most stable nanotubes show negative strain energies and radii below 20 Å, where curvature effects can play a significant role. The band structures show that the selected nanotubes exhibit sizable band gaps and size-dependent electronic properties. More strikingly, the flexoelectricity along the in-plane directions and radial directions in these nanotubes is significantly larger than that in other nanotubes and their 2D counterparts. This work opens up an avenue of structure-property relationships of Janus IV-VI nanotubes and demonstrates giant flexoelectricity in these nanotubes for future electronic and energy applications.