Colloidal photonic crystals (PCs) have been well developed because they are easy to prepare, cost‐effective, and versatile with regards to modification and functionalization. Patterned colloidal PCs ...contribute a novel approach to constructing high‐performance PC devices with unique structures and specific functions. In this review, an overview of the strategies for fabricating patterned colloidal PCs, including patterned substrate‐induced assembly, inkjet printing, and selective immobilization and modification, is presented. The advantages of patterned PC devices are also discussed in detail, for example, improved detection sensitivity and response speed of the sensors, control over the flow direction and wicking rate of microfluidic channels, recognition of cross‐reactive molecules through an array‐patterned microchip, fabrication of display devices with tunable patterns, well‐arranged RGB units, and wide viewing‐angles, and the ability to construct anti‐counterfeiting devices with different security strategies. Finally, the perspective of future developments and challenges is presented.
Bright patterns: Patterned colloidal photonic crystals (PCs) contribute a novel approach to constructing PC devices with unique structures and specific functions. In this Minireview, an overview of the fabrication strategies for patterning colloidal PCs is presented, the advantages of patterned PC devices are discussed, and the perspective of future developments and challenges is addressed.
Inkjet printing has attracted wide attention due to the important applications in fabricating biological, optical, and electrical devices. During the inkjet printing process, the solutes prefer to ...deposit along the droplet periphery and form an inhomogeneous morphology, known as the coffee‐ring effect. Besides, the feature size of printed dots or lines of conventional inkjet printing is usually limited to tens or even hundreds of micrometers. The above two issues greatly restrict the extensive application of printed patterns in high‐performance devices. This paper reviews the recent advances in precisely controlling the printing droplets for high‐resolution patterns and three‐dimensional structures, with a focus on the development to suppress the coffee‐ring effect and minimize the feature size of printed dots or lines. A perspective on the remaining challenges of the research is also proposed.
Inkjet printing has attracted wide attention due to its important applications in fabricating biological, optical, and electrical devices. Recent advances in the precise control of printing droplets for high‐resolution patterns and 3D structures are reviewed, with a focus on suppressing the coffee‐ring effect and minimizing the feature size of printed dots or lines.
With the development of flexible electronics, researchers have endeavored to improve the characteristics of the commonly used indium tin oxide such as brittleness, poor mechanical or chemical ...stability, and scarcity. Currently, many alternative materials have been considered such as conductive polymers, graphene, carbon nanotubes, metallic nanoparticles (NPs), nanowires (NWs), or nanofibers. Among them, silver (Ag) mesh/grid NPs or NWs have been considered as an excellent substitute due to the good transmittance, excellent electrical conductivity, outstanding mechanical robustness, and cost competitiveness. So far, much effort has been devoted to the fabrication of Ag mesh/grid, and many methods such as printing technology, self-assembly, electrospun, hot-pressing, and atomic layer deposition have been reported. Here printing technologies include jet printing, gravure printing, screen printing, nanoimprint lithography, microcontact printing, and flexographic printing. The solution-based self-assembly usually combines with coating, template, or mask assistance. This review summarizes the characteristics of these fabrication methods for the Ag mesh/grid with its related applications in electronics. Then the prospect and challenges of the fabrication methods are discussed, and the new preparation approaches and applications of the Ag mesh/grid are highlighted, which will be of significance for the applications in electronics such as transparent conducting electrodes, organic light-emitting diode, energy harvester, strain sensor, cells, etc.
In this review we focus on recent developments in applications of bio‐inspired special wettable surfaces. We highlight surface materials that in recent years have shown to be the most promising in ...their respective fields for use in future applications. The selected topics are divided into three groups, applications of superhydrophobic surfaces, surfaces of patterned wettability and integrated multifunctional surfaces and devices. We will present how the bio‐inspired wettability has been integrated into traditional materials or devices to improve their performances and to extend their practical applications by developing new functionalities.
Recent developments in applications of bio‐inspired special wettable surfaces are reviewed. The selected topics are roughly divided into three groups, applications of superhydrophobic surfaces, surfaces of patterned wettability, and integrated multifunctional surfaces and devices. We try to present how the bio‐inspired wettability has been integrated into traditional materials or devices to improve their performances and to extend their practical applications by developing new functionalities.
The mechanism of droplet drying is a widely concerned fundamental issue since controlling the deposition morphology of droplet has significant influence on printing, biology pattern, self-assembling ...and other solution-based devices fabrication. Here we reveal a striking different kinetics-controlled deposition regime beyond the ubiquitous coffee-ring effect that suspended particles tend to kinetically accumulate at the air-liquid interface and deposit uniformly. As the interface shrinkage rate exceeds the particle average diffusion rate, particles in vertical evaporation flow will be captured by the descending surface, producing surface particle jam and forming viscous quasi-solid layer, which dramatically prevents the trapped particles from being transported to drop edge and results in uniform deposition. This simple, robust drying regime will provide a versatile strategy to control the droplet deposition morphology, and a novel direction of interface assembling for fabricating superlattices and high quality photonic crystal patterns.
Patterning of controllable surface wettability has attracted wide scientific attention due to its importance in both fundamental research and practical applications. In particular, it is crucial to ...form clear image areas and non-image areas in printing techniques based on wetting and dewetting. This review summarizes the recent research on and applications of patterning of controllable surface wettability for printing techniques, with a focus on the design and fabrication of the precise surface wettability patterning by enhancing the contrast of hydrophilicity and hydrophobicity, such as superhydrophilicity and superhydrophobicity. The selected topics mainly include patterned surface wettability for lithographic printing with different plate-making techniques, patterned surface wettability for microcontact printing with a patterned wetting stamp and special wettability mediated patterning microtransfer printing, patterned surface wettability for inkjet printing with controllable surface wettability of the substrate and printing head to ink, and patterned surface wettability by a combination of different printing techniques. A personal perspective on the future development and remaining challenges of this research is also briefly discussed.
Formamidinium (FA) based perovskites are considered as one of the most promising light‐absorbing perovskite materials owing to their narrower band gap and better thermal stability compared to ...conventional methylammonium‐based perovskites. Constant improvement by using various additives stimulates the potential application of these perovskites. Amine molecules with different structures have been widely used as typical additives in FA‐based perovskite solar cells, and decent performances have been achieved. Thus, a systematic review focusing on structural regulation and functional construction of amines in FA‐based perovskites is of significance. Herein, we analyze the construction mechanism of different structural amines on the functional perovskite crystals. The influence of amine molecules on specific perovskite properties including defect conditions, charge transfer, and moisture resistance are evaluated. Finally, we summarize the design rules of amine molecules for the application in high‐performance FA‐based perovskites and propose directions for the future development of additive molecules.
The structural design of amine molecules is effective for functional construction of perovskite light‐absorbing layer in perovskite solar cells. High‐efficiency and robust perovskite solar cells can be achieved through crystal regulation of formamidinium‐based perovskites and improvement of the specific perovskite properties including defect condition, charge transfer, and moisture resistance.
Inkjet printing has been widely used in functional material patterning for fabrication of optical/electrical devices. The depositing morphologies of inkjet droplets are critical to the resolution and ...performance of resulted functional patterns. This review summarizes various strategies to control the depositing morphologies of inkjet droplets, including suppressing and utilizing coffee-ring effect, employing liquid substrates, developing patterned substrates and controlling droplets coalescence. Moreover, the remaining challenges in controlling inkjet droplets are presented, and the broad research and application prospects of controlling nanomaterial patterning by inkjet printing are proposed.
Three‐dimensional (3D) metal‐halide perovskite solar cells (PSCs) have demonstrated exceptional high efficiency. However, instability of the 3D perovskite is the main challenge for industrialization. ...Incorporation of some long organic cations into perovskite crystal to terminate the lattice, and function as moisture and oxygen passivation layer and ion migration blocking layer, is proven to be an effective method to enhance the perovskite stability. Unfortunately, this method typically sacrifices charge‐carrier extraction efficiency of the perovskites. Even in 2D–3D vertically aligned heterostructures, a spread of bandgaps in the 2D due to varying degrees of quantum confinement also results in charge‐carrier localization and carrier mobility reduction. A trade‐off between the power conversion efficiency and stability is made. Here, by introducing 2D C6H18N2O2PbI4 (EDBEPbI4) microcrystals into the precursor solution, the grain boundaries of the deposited 3D perovskite film are vertically passivated with phase pure 2D perovskite. The phases pure (inorganic layer number n = 1) 2D perovskite can minimize photogenerated charge‐carrier localization in the low‐dimensional perovskite. The dominant vertical alignment does not affect charge‐carrier extraction. Therefore, high‐efficiency (21.06%) and ultrastable (retain 90% of the initial efficiency after 3000 h in air) planar PSCs are demonstrated with these 2D–3D mixtures.
High‐efficiency (21.06%) and durable 2D–3D vertical aligned perovskite solar cells (PSCs) with phase pure 2D perovskite are demonstrated. The phase pure 2D perovskite minimizes photo‐generated charge‐carrier localization in the low‐dimensional perovskite; the dominant vertical alignment does not affect charge‐carrier extraction. The traditional constraint of trade‐off between efficiency and stability in PSC is overcome.
Solar-driven water evaporation represents an environmentally benign method of water purification/desalination. However, the efficiency is limited by increased salt concentration and accumulation. ...Here, we propose an energy reutilizing strategy based on a bio-mimetic 3D structure. The spontaneously formed water film, with thickness inhomogeneity and temperature gradient, fully utilizes the input energy through Marangoni effect and results in localized salt crystallization. Solar-driven water evaporation rate of 2.63 kg m
h
, with energy efficiency of >96% under one sun illumination and under high salinity (25 wt% NaCl), and water collecting rate of 1.72 kg m
h
are achieved in purifying natural seawater in a closed system. The crystalized salt freely stands on the 3D evaporator and can be easily removed. Additionally, energy efficiency and water evaporation are not influenced by salt accumulation thanks to an expanded water film inside the salt, indicating the potential for sustainable and practical applications.
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