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Ilmenite, general formula FeTiO3, has been proposed as possible conversion anode material for lithium- and sodium-ion batteries, with theoretical capacity of 530 mAhg−1. Experimentally, the observed specific capacity for pristine ilmenite is far away from the theoretical value; for this reason, the control of morphology via alkaline hydrothermal treatment has been proposed as possible strategy to improve the electrochemical performance. At the same time FeTiO3 is prone to react with sodium and potassium hydroxide, as already demonstrated by studies on the degradation of ilmenite for the extraction of TiO2. In this paper we demonstrate that the alkaline treatment does not induce a morphological modification of the FeTiO3 powders but involved the degradation of the precursor material with the formation of different phases. A complete physicochemical and electrochemical characterization is performed with the aim of correlating structural and functional properties of the obtained products.

Constructing tandem and multi-blend organic solar cells (OSCs) is an effective way to overcome the absorption limitations of conventional single-junction devices. However, these methods inevitably require tedious multilayer deposition or complicated morphology-optimization procedures. Herein, sequential deposition is utilized as an effective and simple method to fabricate multicomponent OSCs with a double-bulk heterojunction (BHJ) structure of the active layer to further improve photovoltaic performance. Two efficient donor-acceptor pairs, D18-Cl:BTP-eC9 and PM6:L8-BO, are sequentially deposited to form the D18-Cl:BTP-eC9/PM6:L8-BO double-BHJ active layer. In these double-BHJ OSCs, light absorption is significantly improved, and optimal morphology is also retained without requiring a more complicated morphology optimization involved in quaternary blends. Compared to the quaternary blend devices, energy loss (Eloss ) is also reduced by rationally matching each donor with an appropriate acceptor. Consequently, the power conversion efficiency (PCE) is improved from 18.25% for D18-Cl:BTP-eC9 and 18.69% for PM6:L8-BO based binary blend OSCs to 19.61% for the double-BHJ OSCs. In contrast, a D18-Cl:PM6:L8-BO:BTP-eC9 quaternary blend of OSCs exhibited a dramatically reduced PCE of 15.83%. These results demonstrate that a double-BHJ strategy, with a relatively simple processing procedure, can potentially enhance the device performance of OSCs and lead to more widespread use. This work was financially supported by the National Natural Science Foundation of China (NSFC, 21825502, 22075190, 21905185, and 22105135), the School Local Science and Technology Cooperation Special Funds of Sichuan University Zigong City (2020CDYB-28), the Special Fund for Strategic Cooperation between Sichuan University and Yibin Municipal People’s Government (2020CDZG-6), and the Fundamental Research Funds for the Central Universities (YJ201957, YJ202069, and YJ202116).

Flexible perovskite solar cells (f‐PSCs) have attracted increasing attention because of their enormous potential for use in consumer electronic devices. The key to achieve high device performance is to deposit pinhole‐free, uniform and defect‐less perovskite films on the rough surface of polymeric substrates. Here, a solvent engineering to tailor the crystal morphology of FA‐alloyed perovskite films prepared by one‐step blade coating is first deployed. It is found that the use of binary solvents DMF:NMP, rather than the conventional DMF:DMSO, enables to deposit dense and uniform FA‐alloyed perovskite films on both the rigid and flexible substrates. As a decisive step, an embedding 2D/3D perovskite heterostructure is in situ formed by incorporating a small amount of 4‐guanidinobutanoic acid (GBA). Accordingly, photovoltage increases up to 100 mV are realized due to the markedly suppressed nonradiative recombination, leading to high efficiencies of 21.45% and 20.16% on the rigid and flexible substrates, respectively. In parallel, improved mechanical robustness of the flexible devices is achieved due to the presence of the embedded 2D phases. The results underpin the importance of morphology control and defect passivation in delivering high‐performance flexible FA‐alloyed flexible perovskite devices., An embedding 2D/3D heterostructure is in situ formed by incorporating a small amount of 4‐guanidinobutanoic acid, which markedly suppresses nonradiative recombination, leading to high efficiencies of 21.45% and 20.16% for the rigid and flexible perovskite devices, respectively.

With the development of deoxyribonucleic acid (DNA) nanotechnology, various DNA nanostructures and DNA devices have been constructed, which exhibit potential applications in material science and biomedicine. Taking advantage of the programmability and biocompatibility of DNA, novel building block to chemically functionalize DNA with hydrophobic organic molecules has attracted more and more attention. Driving by amphiphilicity, DNA‐organic molecular amphiphiles have been demonstrated to self‐assemble or further induce hierarchically assemblies, providing novel‐specific properties. In this minireview, we summarize the recent progress of DNA organic molecular amphiphiles including their synthesis, self‐assembly behavior in aqueous solution, and the amphiphilic self‐assembly based on hierarchical DNA nano‐structures. We further briefly discuss the perspective of the application of the DNA‐organic molecular amphiphiles.

© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Carbon is one of the most attractive electrode materials for electrochemical energy storage. An ideal electrode structure requires a pore distribution ranging from nanoscale to milliscale to simultaneously enable efficient mass transfer, enlarge the specific surface area, and minimize the electrical resistance. Here, a novel hybrid method to fabricate carbon electrodes with a designable hierarchical pore structure is presented. The proposed manufacturing combines stereolithography, pyrolysis, and chemical activation, which contribute to producing pores in millimeter, micrometer, and nanometer, respectively. The prepared hierarchical microarchitectural material outperforms the commercial carbon paper by five times in current density. Further enhancement in the electrochemical performance can be achieved through optimizing the distribution of hierarchical pores, which is proved feasible in the applications of vanadium redox flow battery and supercapacitor applications.

Currently, nucleic acid aptamers are exploited as robust targeting ligands in the biomedical field, due to their specific molecular recognition, little immunogenicity, low cost, ect. Thanks to the facile chemical modification and high hydrophilicity, aptamers can be site-specifically linked with hydrophobic moieties to prepare aptamer-organic amphiphiles (AOAs), which spontaneously assemble into aptamer-organic amphiphile self-assemblies (AOASs). These polyvalent self-assemblies feature with enhanced target-binding ability, increased resistance to nuclease, and efficient cargo-loading, making them powerful platforms for bioapplications, including targeted drug delivery, cell-based cancer therapy, biosensing, and bioimaging. Besides, the morphology of AOASs can be elaborately manipulated for smarter biomedical functions, by regulating the hydrophilicity/hydrophobicity ratio of AOAs. Benefiting from the boom in DNA synthesis technology and nanotechnology, various types of AOASs, including aptamer-polymer amphiphile self-assemblies, aptamer-lipid amphiphile self-assemblies, aptamer-cell self-assemblies, ect, have been constructed with great biomedical potential. Particularly, stimuli-responsive AOASs with transformable structure can realize site-specific drug release, enhanced tumor penetration, and specific target molecule detection. Herein, the general synthesis methods of oligonucleotide-organic amphiphiles are firstly summarized. Then recent progress in different types of AOASs for bioapplications and strategies for morphology control are systematically reviewed. The present challenges and future perspectives of this field are also discussed.

Advanced materials interfaces 8(14), 2100141 - (2021). doi:10.1002/admi.202100141, Mesoporous $��$-Fe$_2$O$_3$ thin films with large area homogeneity demonstrate tremendous potential in multiple applications. In the present work, the synthesis of morphology-controlled $��$-Fe$_2$O$_3$ thin films is realized with polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP) diblock copolymer assisted sol-gel chemistry. The solvent category (DMF and 1,4-dioxane) and polymer-to-FeCl$_3$ ratio used for the solution preparation are systematically varied to tune the morphology of the thin films. For both solvents, DMF and 1,4-dioxane, nanocluster structures are obtained with low PS-b-P4VP concentration. When the concentration of PS-b-P$_4$VP reaches the critical micelle concentration, spherical and wormlike porous structures are specifically formed in the DMF and 1,4-dioxane solvent system, respectively. Further increasing the polymer-to-FeCl$_3$ ratios leads to the enlargement of the spherical pore sizes in the DMF system, whereas the center-to-center distances of the wormlike structures in the 1,4-dioxane system decrease. Moreover, DMF/1,4-dioxane solvent mixtures with different volume ratios are applied for the sol���gel solution preparation to gain more insight into how the solvent selectivity affects the thin film morphology. By adjusting the preferential affinity of the solvent mixture to the polymer blocks, a spherical to wormlike pore shape transition is observed with a critical $����$ value of around 0.77., Published by Wiley-VCH, Weinheim

To meet the future need for clean and sustainable energies, there has been considerable interest in the development of triboelectric nanogenerators (TENGs) that scavenge waste mechanical energies. The performance of a TENG at the macroscale is determined by the multifaceted role of surface and interface properties at the nanoscale, whose understanding is critical for the future development of TENGs. Therefore, various protocols from the atomic to the macrolevel for fabrication and tuning of surfaces and interfaces are required to obtain the desired TENG performance. These protocols branch out into three categories: chemical engineering, physical engineering, and structural engineering. Chemical engineering is an affordable and optimal strategy for introducing more surface polarities and higher work functions for the improvement of charge transfer. Physical engineering includes the utilization of surface morphology control, and interlayer interactions, which can enhance the active interfacial area and electron transfer capacity. Structural engineering at the macroscale, which includes device and electrode design/modifications has a considerable effect on the performance of TENGs. Future challenges and promising research directions related to the construction of next-generation TENG devices, taking into consideration “interfaces” are also presented.

Mesoporous CeO2 with flowerlike and cottonlike hierarchical structures were prepared through a facile solvothermal strategy by using cerium glycolate as precursors. In the whole synthesis process, the solvothermal reaction time plays an important role in morphology control. Structure and composition information of the corresponding cerium glycolate were obtained and compared by using X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Oriented attachment/anisotropic crystal growth with Ostwald ripening/multistep splitting process mechanism was proposed for the formation of the cerium glycolate precursor. The catalytic test results show that the final CeO2 microparticles exhibit enhanced CO conversion performance and better reduction behavior than pure ceria. Furthermore, as a good support, the synthesized Au/CeO2 samples demonstrate higher catalytic activity in the oxidation of CO than pure ceria.

The booming development of organometal halide perovskites in recent years has prompted the exploration of morphology-control strategies to improve their performance in photovoltaic, photonic, and optoelectronic applications. However, the preparation of organometal halide perovskites with high hierarchical architecture is still highly challenging and a general morphology-control method for various organometal halide perovskites has not been achieved. A mild and scalable method to prepare organometal halide perovskites in inverse opal morphology is presented that uses a polystyrene-based artificial opal as hard template. Our method is flexible and compatible with different halides and organic ammonium compositions. Thus, the perovskite inverse opal maintains the advantage of straightforward structure and band gap engineering. Furthermore, optoelectronic investigations reveal that morphology exerted influence on the conducting nature of organometal halide perovskites.

Calcium phosphate nanomaterials with controllable morphology and mesostructure were synthesized via a rapid and energy efficient microwave method. An increase in aspect ratio from nanoplates to nanorods was achieved by increasing the solvent chain length, accompanied by a subsequent about 23% increase in surface area and porosity. Control of mesoporosity was also achieved by varying the synthesis time and quantity of H2O in the reaction solvent. Comparative studies were carried out using conventional heating (CON) and room temperature co‐precipitation (RT) methods. It was found that microwave synthesis produces nanomaterials with about 50% higher yields, 7.5/1.7 times higher surface area and 3/5 times higher pore volume than RT/CON materials respectively, as well as having a lower distribution of particle size/shape (lower standard deviation values of their dimensions). Furthermore, in vitro protein loading tests of microwave synthesized mesoporous calcium phosphate materials showed an enhanced loading efficiency of bovine serum albumin (3–7 times), as compared with non‐mesostructured products from room temperature precipitation, in accordance with their larger surface area and porosity. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3781–3789, 2015.