MOF‐Based Hierarchical Structures for Solar‐Thermal Clean Water Production

Solar‐thermal water evaporation, as a promising method for clean water production, has attracted increasing attention. However, solar water evaporators that exhibit both high water vapor generation ability and anti‐oil‐fouling ability have not been reported. Here, a unique metal–organic‐framework‐based hierarchical structure, referred to as MOF‐based hierarchical structure (MHS), is rationally designed and prepared, which simultaneously displays a high solar absorption and a superhydrophilic and underwater superoleophobic surface property. As a proof‐of‐concept application, a device prepared from the MHS can achieve a high solar‐thermal water evaporation rate of 1.50 kg m^?2 h^?1 under 1 sun illumination. Importantly, the MHS also possesses an excellent anti‐oil‐fouling property, ensuring its superior water evaporation performance even in oil‐contaminated water. The high solar‐thermal water evaporation rate and anti‐oil‐fouling property make the MHS a promising material for the solar‐thermal water production.     

Design of Diketopyrrolopyrrole (DPP)‐Based Small Molecules for Organic‐Solar‐Cell Applications

After the first report in 2008, diketopyrrolopyrrole (DPP)‐based small‐molecule photovoltaic materials have been intensively explored. The power conversion efficiencies (PCEs) for the DPP‐based small‐molecule donors have been improved up to 8%. Furthermore, through judicious structure modification, DPP‐based small molecules can also be converted into electron‐acceptor materials, and, recently, some exciting progress has been achieved. The development of DPP‐based photovoltaic small molecules is summarized here, and the photovoltaic performance is discussed in relation to structural modifications, such as the variations of donor–acceptor building blocks, alkyl substitutions, and the type of conjugated bridges, as well as end‐capped groups. It is expected that the discussion will provide a guideline in the exploration of novel and promising DPP‐containing photovoltaic small molecules.     

Towards High‐Performance Bioinspired Composites

Biological composites have evolved elaborate hierarchical structures to achieve outstanding mechanical properties using weak but readily available building blocks. Combining the underlying design principles of such biological materials with the rich chemistry accessible in synthetic systems may enable the creation of artificial composites with unprecedented properties and functionalities. This bioinspired approach requires identification, understanding, and quantification of natural design principles and their replication in synthetic materials, taking into account the intrinsic properties of the stronger artificial building blocks and the boundary conditions of engineering applications. In this progress report, the scientific and technological questions that have to be addressed to achieve this goal are highlighted, and examples of recent research efforts to tackle them are presented. These include the local characterization of the heterogeneous architecture of biological materials, the investigation of structure–function relationships to help unveil natural design principles, and the development of synthetic processing routes that can potentially be used to implement some of these principles in synthetic materials. The importance of replicating the design principles of biological materials rather than their structure per se is highlighted, and possible directions for further progress in this fascinating, interdisciplinary field are discussed.     

Photoswitching and Thermoresponsive Properties of Conjugated Multi‐chromophore Nanostructured Materials

Conjugated multi‐chromophore organic nanostructured materials have recently emerged as a new class of functional materials for developing efficient light‐harvesting, photosensitization, photocatalysis, and sensor devices because of their unique photophysical and photochemical properties. Here, we demonstrate the formation of various nanostructures (fibers and flakes) related to the molecular arrangement (H‐aggregation) of quaterthiophene (QTH) molecules and their influence on the photophysical properties. XRD studies confirm that the fiber structure consists of >95% crystalline material, whereas the flake structure is almost completely amorphous and the microstrain in flake‐shaped QTH is significantly higher than that of QTH in solution. The influence of the aggregation of the QTH molecules on their photoswitching and thermoresponsive photoluminescence properties is revealed. Time‐resolved anisotropic studies further unveil the relaxation dynamics and restricted chromophore properties of the self‐assembled nano/microstructured morphologies. Further investigations should pave the way for the future development of organic electronics, photovoltaics, and light‐harvesting systems based on π‐conjugated multi‐chromophore organic nanostructured materials.     

A Full Compositional Range for a (Ga1‐x Zn x )(N1‐x O x ) Nanostructure: High Efficiency for Overall Water Splitting and Optical Properties

Bulk (Ga_1‐x Zn _x )(N_1‐x O _x ) as a photocatalyst has received increasing attention as a potential solution for the energy shortage challenge; however, its catalytic performance is highly limited by its bulk form. To improve the photochemical potential, the nanoscale form of this multiple‐metal oxynitrides is desirable. In this work, a new type of (Ga_1‐x Zn _x )(N_1‐x O _x ) nanostructure is obtained. Its composition can tuned to the full range (0.18 < x < 0.95). The (Ga_1‐x Zn _x )(N_1‐x O _x ) nanostructure exhibits excellent photocatalytic activity for overall water splitting, and the highest quantum efficiency of (Ga_1‐x Zn _x )(N_1‐x O _x ) is as high as 17.3% under visible light irradiation. Using this new type of (Ga_1‐x Zn _x )(N_1‐x O _x ) nanostructure, the narrowing of the bandgap for (Ga_1‐x Zn _x )(N_1‐x O _x ) is not only due to an increase in the valence band maximum, but it is also related to a decrease in the conduction band minimum.