Emergence of Two-Dimensional Inorganic Molecular Crystals

ConspectusThe breakthrough discovery of graphene in 2004 has catalyzed an explosion of interest in two-dimensional (2D) materials. This seminal moment set off a flurry of research endeavors aimed at exploring the vast landscape of 2D materials for their unique properties and potential applications. These materials, with typical graphene-like layered structure, not only served as a fertile ground for fundamental research in condensed-matter physics but also paved the way for groundbreaking advancements in various technological domains. In 2019, we introduced the first-ever 2D inorganic molecular crystal (IMC) known as Sb2O3 and unveiled a novel structural configuration characterized by small inorganic molecules bonded together through van der Waals (vdW) interactions. This revelation opened a new frontier in the exploration of 2D IMCs, sparking widespread interest to explore their unique properties and potential applications. In this Account, we introduce the concept of 2D IMCs and provide a comprehensive overview of the pioneering research conducted in this burgeoning field. The allure of uncovering novel properties and unlocking the transformative potential of materials possessing unconventional structures has propelled 2D IMCs into the spotlight of scientific inquiry. Since the inception of the concept of 2D IMCs, our research efforts have been dedicated to pushing the boundaries of this emerging field. We have not only expanded the repertoire of 2D IMCs by discovering new materials with diverse properties but also delved into uncharted territory by uncovering novel phenomena through the strategic modulation of interactions between inorganic molecules, and we have unraveled how the molecular interactions can significantly modulate the charge transport within IMCs. Furthermore, our exploration into the practical applications of 2D IMCs has yielded promising results. We showcased their potential applications as versatile vdW dielectrics in advanced 2D electronics. Owing to their unique structural characteristics, 2D IMCs, which can form a high-quality vdW interface with 2D channels in 2D devices and greatly optimize their performance, offer unparalleled advantages over traditional dielectrics, and underscore their immense potential in driving technological innovation of 2D devices. It is evident that the exploration of 2D IMCs presents a wealth of untapped research opportunities. Through this Account, we aim to provide a solid foundation for researchers to familiarize themselves with the intricacies of 2D IMCs and kindle their curiosity in exploring the boundless possibilities offered by these extraordinary materials. As we continue to chart new frontiers in the realm of 2D materials, we are optimistic that the journey ahead will be marked by groundbreaking discoveries and transformative advancements, propelled by the collective efforts of the scientific community.