Introduction to materials chemistry at Xi’an Jiaotong University

Xi'an Jiaotong University (XJTU) is one of the oldest universities in China, and is also on the list of World-Class Universities and First-Class Disciplines by the Ministry of Education of China. Currently, XJTU has four campuses: the Xingqing campus, the Yanta campus, the Qujiang campus and the Western China Science & Technology Innovation Harbor (IHarbor). Among them, IHarbor has established 8 major research platforms, 25 institutes and 100 scientific research bases to serve scientific research in China. The university also has faculty and staff totalling 6137 people, including 3081 full-time teachers. XJTU is also a comprehensive research university with ten major categories of disciplines. Among them, chemistry, materials science, engineering, medicine and other related disciplines, combine to contribute to the development of materials chemistry at XJTU.

In 2020, the School of Chemistry was established, covering the Programs of Material Chemistry and Applied Chemistry. This further promotes the fast development of materials chemistry at XJTU. Motivated by the essential role of materials chemistry in fundamental research and applications, and also based on the significant progress of materials chemistry at XJTU, this themed collection was organized to highlight the outstanding scientists and their research at XJTU. This themed collection includes 1 review article and 14 research articles by scientists from different schools – the School of Chemistry, the School of Materials Science and Engineering, the School of Electronic and Information Engineering as well as the Frontier Institute of Science and Technology.

In the field of luminescent materials, Prof. Gang He reports the viologen derivatives of 9,10-azaboraphenanthrene (BNPV²⁺) (DOI: 10.1039/D1QM00327E). This aggregation-induced emission (AIE)-active molecule exhibits electro-chromic (EC) behavior in solution, and simultaneous EC and electrofluorochromic (EFC) behaviors in film, finally providing the application of reversible data encryption. A poly(vinylidene fluoride) based fluoropolymer (P(VDF–ATrFE)) is prepared by Prof. Zhicheng Zhang as the fluorescence sensor to detect copper ions (DOI: 10.1039/D1QM00307K). In this case, excellent selectivity and highly efficient quantitative analysis of Cu²⁺ in the organic phase can be obtained. Prof. Mingming Zhang and Xianglong Duan present a convenient method to develop the fluorescent metallacycle-cored supramolecular polymers, and also reveal the effect of the linker length and the solvent on their morphology (DOI: 10.1039/D1QM00265A).

Prof. Shujiang Ding prepared a sandwich-like CoSe₂@NC/rGO composite (DOI: 10.1039/D1QM00362C). This unique 3D structure results in significantly enhanced electronic conductivity and specific surface area. Interestingly, the volume expansion and the peeling of active materials during cycling can also be alleviated here. Prof. Xianfeng Du and Lilong Xiong report N-doped carbon nanotube (NCNT)-supported Pt nanoparticle (NCNTs/Pt) electrodes (DOI: 10.1039/D1QI00377A). In contrast to the stainless steel electrodes, a 9.04% reduction at a formation voltage of 150 V is observed when employing the NCNTs/Pt electrodes to test the aluminum anodization energy consumption. Prof. Yunchuan Xie and Zhicheng Zhang fabricate a novel P(VDF-HFP)/MS (poly(vinylidene fluoride-hexafluoropropylene)/poly(methyl methacrylate-co-styrene)) composite film (DOI: 10.1039/D1QM00105A). This results in an enhanced energy density (U_e) of 20 J cm⁻³ and discharge efficiency (η ≈ 81%), indicating the great potential to achieve PVDF-based dielectrics for energy storage capacitors.

As for organic electronics, mono-, di- and tri-nuclear Pt^II(C^N)(N-donor ligand)Cl complexes are designed by Prof. Guijiang Zhou and Zhaoxin Wu (DOI: 10.1039/D1QM00172H). Among them, the highest electroluminescence efficiency in solution-processed organic light-emitting devices (OLEDs) can be obtained in Ph-PAYPt2 with the external quantum efficiency (η_ext) of up to 12.4%, a power efficiency (η_p) of 31.8 lm W⁻¹ and a current efficiency (η_L) of 43.8 cd A⁻¹. Prof. Xiaolong Yang and Guijiang Zhou also report two thermally stable dinuclear Pt(II) complexes based on diphenylsulfone and arylboron building blocks, which display pure yellow emission with CIE coordinates at (0.44, 0.55) in solution-processed OLEDs (DOI: 10.1039/D1QM00507C). The 2 wt% doped devices also exhibit excellent performance with a η_ext of 21.54% and a η_L of 76.64 cd A⁻¹. 2D lead-free bimetallic iodide-based hybrid compounds with optical band gaps of 2.18 eV and 2.39 eV, respectively, are developed by Prof. Yan-Zhen Zheng, showing the great potential for application in light detection (DOI: 10.1039/D0QM00762E).

Prof. Yanfeng Zhang introduces the imidazolidinyl urea as a multiple hydrogen-bonding motif to prepare transparent and degradable polyurethane elastomers (DOI: 10.1039/D1QM00476J). This leads to a breaking strength and toughness of up to 24.9 MPa and 168.2 MJ m⁻³, respectively. Prof. Demei Yu reports facilely fabricated microlens arrays (MLAs) with well-controlled curvature, and these high performance MLAs indicate the great potential in flexible optical micro-devices (DOI: 10.1039/D1QM00519G). Additionally, the progress of research on cross-linked polymers containing B–O bonds is reviewed by Prof. Xinli Jing (DOI: 10.1039/D1QM00514F). The synthesis, structures and properties for these cross-linked polymers are also highlighted.

In the field of biomaterials, by using stimulated emission depletion nanoscopy and two-photon fluorescence microscopy, Prof. Dongfeng Dang, Lingjie Meng and Ben Zhong Tang develop a lipid droplets-specific imaging platform of AIE-active DTPA-BT-M for super-resolution cellular imaging and deep-penetration tissue imaging (DOI: 10.1039/D0QM00682C). Prof. Lingjie Meng and Dongfeng Dang also design the donor–acceptor–donor (D–A–D)-type AIEgen of DTPA-BBTD to balance radiative decay and non-radiative decay, thus providing a single-molecule-triggered high performance photo-theranostic platform for diagnosis and cancer therapy (DOI: 10.1039/D0QM01035A). Prof. Lei and his co-workers find that the osteoblastic differentiation of BMSCs can be modulated by the microRNA-5106 through liposome-based delivery and transfection. This may provide a new therapeutic method and also an osteoblastic molecular mechanism to enhance the bone tissue regeneration (DOI: 10.1039/D1QM00367D).

It is noted that although this themed collection could not cover all the research in materials chemistry at XJTU, we hope it can show the fast development of materials chemistry at this university, thus forming solid collaborations with other institutes. Finally, we also appreciate the whole editorial team at Materials Chemistry Frontiers for giving us the chance to organize this themed collection.

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