The self-limited chemical vapor deposition of uniform single-layer graphene on Cu foils generated significant interest when it was initially discovered. Soon after, the fabrication of real uniform graphene was found to need extremely precise control of the growth conditions. Slight deviations terminate the self-limiting homogeneous growth, inevitably leading to multilayer graphene formation. Here we propose an innovative way to utilize liquid metals to resolve this thorny problem. In stark contrast to the low carbon solubility found in solid metals (e.g., Cu), catalytically decomposed carbon atoms are embedded in liquid metals. During cooling, the homogeneous solidified surface forms from the quasi-atomic smooth liquid surface, and carbon precipitation is blocked by the frozen metal lattices, which are insoluble to carbon. The underlying liquid bulk acts as a container to buffer the excess carbon supply, which normally would lead to the formation of multilayer graphene in the conventional CVD process. As a result, the growth of graphene becomes governed by a self-limiting surface catalytic process and is robust to variations in growth conditions. With simplicity, scalability, and a large growth window, the use of liquid metals provides an attractive solution to obtain uniform graphene.

The idea flat surface, superb thermal conductivity and excellent optical transmittance of single-layer graphene promise tremendous potential for graphene as a material for transparent defoggers. However, the resistance of defoggers made from conventional transferred graphene increases sharply once both sides of the film are covered by water molecules which, in turn, leads to a temperature drop that is inefficient for fog removal. Here, the direct growth of large-area and continuous graphene films on quartz is reported, and the first practical single-layer graphene defogger is fabricated. The advantages of this single-layer graphene defogger lie in its ultrafast defogging time for relatively low input voltages and excellent defogging robustness. It can completely remove fog within 6 s when supplied a safe voltage of 32 V. No visible changes in the full defogging time after 50 defogging cycles are observed. This outstanding performance is attributed to the strong interaction forces between the graphene films and the substrates, which prevents the permeation of water molecules. These directly grown transparent graphene defoggers are expected to have excellent prospects in various applications such as anti-fog glasses, auto window and mirror defogging.

The high-quality and low-cost of the graphene preparation method decide whether graphene is put into the applications finally. Enormous efforts have been devoted to understand and optimize the CVD process of graphene over various d-block transition metals (e.g. Cu, Ni and Pt). Here we report the growth of uniform high-quality single-layer, single-crystalline graphene flakes and their continuous films over p-block elements (e.g. Ga) liquid films using ambient-pressure chemical vapor deposition. The graphene shows high crystalline quality with electron mobility reaching levels as high as 7400 cm2 V−1s−1 under ambient conditions. Our employed growth strategy is ultra-low-loss. Only trace amounts of Ga are consumed in the production and transfer of the graphene and expensive film deposition or vacuum systems are not needed. We believe that our research will open up new territory in the field of graphene growth and thus promote its practical application.

The quality of graphene grown via chemical vapor deposition still has very great disparity with its theoretical property due to the inevitable formation of grain boundaries. The design of single-crystal substrate with an anisotropic twofold symmetry for the unidirectional alignment of graphene seeds would be a promising way for eliminating the grain boundaries at the wafer scale. However, such a delicate process will be easily terminated by the obstruction of defects or impurities. Here we investigated the isotropic growth behavior of graphene single crystals via melting the growth substrate to obtain an amorphous isotropic surface, which will not offer any specific grain orientation induction or preponderant growth rate toward a certain direction in the graphene growth process. The as-obtained graphene grains are isotropically round with mixed edges that exhibit high activity. The orientation of adjacent grains can be easily self-adjusted to smoothly match each other over a liquid catalyst with facile atom delocalization due to the low rotation steric hindrance of the isotropic grains, thus achieving the smoothing stitching of the adjacent graphene. Therefore, the adverse effects of grain boundaries will be eliminated and the excellent transport performance of graphene will be more guaranteed. What is more, such an isotropic growth mode can be extended to other types of layered nanomaterials such as hexagonal boron nitride and transition metal chalcogenides for obtaining large-size intrinsic film with low defect.

A h‐BN self‐aligned single‐crystal array (SASCA) that exhibits orderly alignment and uniformly distribution is controllably synthesized on a liquid Cu surface for the first time. The h‐BN SASCA exhibits highly accordant spatial orientation and homogenous domain size, which can realize highly integrated and individually switching field‐effect transistors when serving as a gate dielectric. Circular h‐BN single‐crystals, which are considered to be the building blocks of h‐BN SASCA, are also observed.

The controllable synthesis of uniform graphene with a specific layer number is crucial for both fundamental research and emerging applications due to the high sensitivity of the various extraordinary physicochemical properties of graphene to its layer numbers. However, the excessive segregation of extra C, the inactivation of the self-limiting of Cu and the superabundant nucleation at grain boundaries and defect sites render that the controllable synthesis of uniform graphene is still a challenge. By the employment of various solid and liquid metals with quasi-atomically smooth surfaces to avoid defects or grain boundaries, a series of studies have been performed and significant improvements have been achieved in the controllable synthesis of uniform graphene films. In this review, the representative strategies of designing catalytic substrates, including polycrystalline metals, single-crystalline metals, binary metal alloys and liquid metals, are highlighted. The future of the controllable synthesis of uniform graphene is also discussed.

Humans have numerous senses, wherein vision, hearing, smell, taste, and touch are considered as the five conventionally acknowledged senses. Triggered by light, sound, or other physical stimulations, the sensory organs of human body are excited, leading to the transformation of the afferent energy into neural activity. Also converting other signals into electronical signals, graphene‐based film shows its inherent advantages in responding to the tiny stimulations. In this review, the human‐like senses and reflexes of graphene‐based films are presented. The review starts with the brief discussions about the preparation and optimization of graphene‐based film, as where as its new progress in synthesis method, transfer operation, film‐formation technologies and optimization techniques. Various human‐like senses of graphene‐based film and their recent advancements are then summarized, including light‐sensitive devices, acoustic devices, gas sensors, biomolecules and wearable devices. Similar to the reflex action of humans, graphene‐based film also exhibits reflex when under thermal radiation and light actuation. Finally, the current challenges associated with human‐like applications are discussed to help guide the future research on graphene films. At last, the future opportunities lie in the new applicable human‐like senses and the integration of multiple senses that can raise a revolution in bionic devices.

The synthesis and integration of core-shell materials have been extensively explored in three-dimensional nanostructures, while they are hardly ever extended into the emerging two-dimensional (2D) research field. Herein, demonstrated by graphene (G) and hexagonal boron nitride (h-BN) and via a sequential chemical vapor deposition method, we succeed for the first time in synthesizing 2D h-BN-G core-shell arrays (CSA), which possess extremely high uniformity in shapes, sizes and distributions. Each of the core-shell units is composed of G ring-shaped shell internally filled with h-BN circular core. In addition, we perform simulations to further explain the self-symmetrical etching growth mechanism of the h-BN-G CSA, demonstrating its potential to be used as an efficient synthetic method suitable for other 2D CSA systems.