Qian Song

Bio: Qian Song is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Perovskite (structure) & Superlattice. The author has an hindex of 11, co-authored 17 publications receiving 492 citations.

Selective Surface Enhanced Raman Scattering for Quantitative Detection of Lung Cancer Biomarkers in Superparticle@MOF Structure.

Abstract: Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF-8 layer is coated onto a self-assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor-specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS-active GSPs substrates through a ZIF-8 channel. Through a Schiff base reaction with 4-aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.

Coordination mode engineering in stacked-nanosheet metal-organic frameworks to enhance catalytic reactivity and structural robustness

Abstract: Optimising the supported modes of atom or ion dispersal onto substrates, to synchronously integrate high reactivity and robust stability in catalytic conversion, is an important yet challenging area of research. Here, theoretical calculations first show that three-coordinated copper (Cu) sites have higher activity than four-, two- and one-coordinated sites. A site-selective etching method is then introduced to prepare a stacked-nanosheet metal-organic framework (MOF, CASFZU-1)-based catalyst with precisely controlled coordination number sites on its surface. The turnover frequency value of CASFZU-1 with three-coordinated Cu sites, for cycloaddition reaction of CO2 with epoxides, greatly exceed those of other catalysts reported to date. Five successive catalytic cycles reveal the superior stability of CASFZU-1 in the stacked-nanosheet structure. This study could form a basis for the rational design and construction of highly efficient and robust catalysts in the field of single-atom or ion catalysis.

General Strategy to Optimize Gas Evolution Reaction via Assembled Striped-Pattern Superlattices.

Abstract: Redesigning heterogeneous catalysts so that they can simultaneously integrate the efficiency and durability under reaction environments with respect to gas fuel production, such as hydrogen (H2), o...

Large-Scale, Long-Range-Ordered Patterning of Nanocrystals via Capillary-Bridge Manipulation.

Abstract: Deterministic assembly of nanoparticles with programmable patterns is a core opportunity for property-by-design fabrication and large-scale integration of functional materials and devices. The wet-chemical-synthesized colloidal nanocrystals are compatible with solution assembly techniques, thus possessing advantages of high efficiency, low cost, and large scale. However, conventional solution process suffers from tradeoffs between spatial precision and long-range order of nanocrystal assembly arising from the uncontrollable dewetting dynamics and fluid flow. Here, a capillary-bridge manipulation method is demonstrated for directing the dewetting of nanocrystal inks and deterministically patterning long-range-ordered superlattice structures. This is achieved by employing micropillars with programmable size, arrangement, and shape, which permits deterministic manipulation of geometry, position, and dewetting dynamics of capillary bridges. Various superlattice structures, including one-dimensional (1D), circle, square, pentagon, hexagon, pentagram, cross arrays, are fabricated. Compared to the glassy thin films, long-range-ordered superlattice arrays exhibit improved ferroelectric polarization. Coassembly of nanocrystal superlattice and organic functional molecule is further demonstrated. Through introducing azobenzene into superlattice arrays, a switchable ferroelectric polarization is realized, which is triggered by order-disorder transition of nanocrystal stacking in reversible isomerization process of azobenzene. This method offers a platform for patterning nanocrystal superlattices and fabricating microdevices with functionalities for multiferroics, electronics, and photonics.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

Abstract: Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

Abstract: It is conventionally assumed that the growth of monodisperse colloidal nanocrystals requires a temporally discrete nucleation followed by monomer attachment onto the existing nuclei. However, recent studies have reported violations of this classical growth model, and have suggested that inter-particle interactions are also involved during the growth. Mechanisms of nanocrystal growth still remain controversial. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution onto the existing particles or by coalescence between the particles. Surprisingly, an initially broad size distribution of the nanocrystals can spontaneously narrow. We suggest that nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies. These observations are expected to be highly relevant for other nanocrystal systems.

Metal Halide Perovskite Nanocrystals: Synthesis, Post-Synthesis Modifications and Their Optical Properties

Abstract: Metal halide perovskites represent a flourishing area of research, driven by both their potential application in photo-voltaics and optoelectronics, and for the fundamental science underpinning their unique optoelectronic properties. The advent of colloidal methods for the synthesis of halide perovskite nanocrystals has brought to the attention inter-esting aspects of this new type of materials, above all their defect-tolerance. This review aims to provide an updated survey of this fast-moving field, with a main focus on their colloidal synthesis. We examine the chemistry and the ca-pability of different colloidal synthetic routes to control the shape, size and optical properties of the resulting nano-crystals. We also provide an up to date overview of their post-synthesis transformations, and summarize the various so-lution processes aimed at fabricating halide perovskite-based nanocomposites. We then review the fundamental optical properties of halide perovskite nanocrystals, by focusing on their linear optical properties, on the effects of quantum confinement and, then, on the current knowledge of their exciton binding energies. We also discuss the emergence of non-linear phenomena such as multiphoton absorption, biexcitons and carrier multiplication. At last, we provide an outlook in the field, with the most cogent open questions and possible future directions.

Metal Halide Perovskite Nanocrystals: Synthesis, Post-Synthesis Modifications, and Their Optical Properties.

Abstract: Metal halide perovskites represent a flourishing area of research, which is driven by both their potential application in photovoltaics and optoelectronics and by the fundamental science behind their unique optoelectronic properties. The emergence of new colloidal methods for the synthesis of halide perovskite nanocrystals, as well as the interesting characteristics of this new type of material, has attracted the attention of many researchers. This review aims to provide an up-to-date survey of this fast-moving field and will mainly focus on the different colloidal synthesis approaches that have been developed. We will examine the chemistry and the capability of different colloidal synthetic routes with regard to controlling the shape, size, and optical properties of the resulting nanocrystals. We will also provide an up-to-date overview of their postsynthesis transformations, and summarize the various solution processes that are aimed at fabricating halide perovskite-based nanocomposites. Furthermore, we...

Synthesis of micro/nanoscaled metal-organic frameworks and their direct electrochemical applications.

Abstract: As a new class of crystalline porous materials, metal-organic frameworks (MOFs) have received great attention owing to their unique advantages of ultrahigh surface area, large pore volume and versatile applications. Developing different strategies to control the morphology and size of MOFs is very important for their practical applications. Recently, micro/nanosized MOFs have been regarded as promising candidates for electrode materials with excellent performances, which not only bridge the gap between fundamental MOF science and forward-looking applications, but also provide an opportunity to make clear the relationship between morphologies and properties. This review focuses on the design and fabrication of one-, two- and three-dimensional MOFs at micro/nanoscale, and their direct applications in batteries, supercapacitors and electrocatalysis. A discussion on challenges and future prospects of the synthesis and electrochemical applications of micro/nanoscaled MOF materials is presented.