Doping High-Mobility Donor : Acceptor Copolymer Semiconductors with an Organic Salt for High-Performance Thermoelectric Materials

Organic semiconductors (OSCs) are attractive for fabrication of thermoelectric devices with low cost, large area, low toxicity, and high flexibility. In order to achieve high-performance organic thermoelectric devices (OTEs), it is essential to develop OSCs with high conductivity (σ), large Seebeck coefficient (S), and low thermal conductivity (κ). It is equally important to explore efficient dopants matching the need of thermoelectric devices. The thermoelectric performance of a high-mobility donor–acceptor (D–A) polymer semiconductor, which is doped by an organic salt, is studied. Both a high p-type electrical conductivity approaching 4 S cm−1 and an excellent power factor (PF) of 7 µW K−2 m−1 are obtained, which are among the highest reported values for polymer semiconductors. Temperature-dependent conductivity, Seebeck coefficient and power factor of the doped materials are systematically investigated. Detailed analysis on the results of thermoelectric measurements has revealed a hopping transport in the materials, which verifies the empirical relationship: S ∝ σ−1/4 and PF ∝ σ1/2. The results demonstrate that D–A copolymer semiconductors with proper combination of dopants have great potential for fabricating high-performance thermoelectric devices. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Optimized landslide susceptibility prediction based on SBAS-InSAR: case study of the Jiuzhaigou Ms7.0 earthquake

Earthquake-induced landslides can cause severe surface damage and casualties, posing a serious threat to the overall ecological environment and social stability. Traditional landslide susceptibility prediction (LSP) techniques often suffer from low effectiveness and precision, necessitating the exploration of remote sensing technology. However, this research in this area is limited, and the development of high-performance prediction models remains a pressing scientific issue. This study focuses on the Ms7.0 earthquake in Jiuzhaigou on 8 August 2017. To investigate the optimal integration of remote sensing technology with traditional LSP techniques, the study applies collaborative factor analysis and contingency matrix methods to create four new coupling models (SVM-I, SVM-II, RF-I, RF-II), followed by a comprehensive performance evaluation of these models. The results indicate that the integration of SAR-derived surface deformation data significantly enhances the accuracy of Landslide Susceptibility Mapping (LSM). Comparing the model performance with the receiver operating characteristic curve and landslide density, the reliability and prediction performance of the RF-I model are outstanding, reflecting that the improved method based on the InSAR collaborative machine learning model with shape variables along the slope direction can optimize the accuracy of the LSM, and has better performance and robustness in earthquake landslide susceptibility evaluation

Functional Scaffolds from AIE Building Blocks

The functional design of molecular materials is an enduring pursuit. In some cases, molecular ensembles can exhibit new properties and functions that are not found in their molecular species. This evolutionary process occurs primarily at the mesoscale aggregate level, which motivates the design of materials outside of the classical “structure-property correlation” box. By reviewing scaffolding materials with precisely organized aggregation-induced emission (AIE) chromophores, we investigate the interplay of these building blocks in the evolving luminescence and other functions. They can work synergistically and collectively at the molecular-length scale, leading to stronger luminescence behaviors, evolution of new emission modes, and integration of versatility for functional applications at the macroscale level. Thus, this may open new doors to advanced luminescent materials and beyond, even giving materials science new perspectives on structural to functional design. © 2020 Elsevier Inc.In materials science, the whole is typically greater than the sum of the parts. This principle has been spotlighted in advanced molecular materials, where the assembly of fundamental building blocks at the molecular scale can lead to a hierarchy of materials with enhanced properties, sometimes with new functions at larger scales. One exciting example is the phenomenon of aggregation-induced emission (AIE). In contrast to a single free molecule that exhibits no or weak luminescence, aggregation of AIE fluorogens can produce a plethora of solid-state luminescent materials. In this Review, we explore the synergistically collective behaviors of multiple AIE units in ordered arrays by investigating scaffolding materials ranging from discrete cage compounds to infinite crystalline frameworks. As shown, AIE building blocks endow the materials with intriguing luminescence properties: intensive and tunable emission, unprecedented activities in specific emission modes (such as room temperature phosphorescence, multiphoton-excitable luminescence, coherent harmonic generation, circularly polarized luminescence, and lasing), stimulus-responsive luminescence for chemosensing and bioimaging, etc. In contrast, conventional building blocks frequently suffer from faint or extinguished emission in these scaffolding materials. Furthermore, the self-reporting luminescence properties endowed by built-in AIE building blocks were integrated into essential functions such as matter adsorption and diffusion, light harvesting, and photocatalysis. In addition to their unique configurations, processability, and facile derivatization chemistries, AIE-active building blocks in scaffolds act as the origin of a new phase of matter. This work helps to motivate the exploration of “advisable aggregation effects” in emerging functions of material systems. © 2020 Elsevier Inc.In materials science, the whole is typically greater than the sum of the parts. This principle has been spotlighted in advanced molecular materials, where the assembly of fundamental building blocks at the molecular scale can lead to a hierarchy of materials with enhanced properties, sometimes with new functions at larger scales. One exciting example is the phenomenon of aggregation-induced emission (AIE). In contrast to a single free molecule that exhibits no or weak luminescence, aggregation of AIE fluorogens can produce a plethora of solid-state luminescent materials. In this Review, we explore the synergistically collective behaviors of multiple AIE units in ordered arrays by investigating scaffolding materials ranging from discrete cage compounds to infinite crystalline frameworks. As shown, AIE building blocks endow the materials with intriguing luminescence properties: intensive and tunable emission, unprecedented activities in specific emission modes (such as room temperature phosphorescence, multiphoton-excitable luminescence, coherent harmonic generation, circularly polarized luminescence, and lasing), stimulus-responsive luminescence for chemosensing and bioimaging, etc. In contrast, conventional building blocks frequently suffer from faint or extinguished emission in these scaffolding materials. Furthermore, the self-reporting luminescence properties endowed by built-in AIE building blocks were integrated into essential functions such as matter adsorption and diffusion, light harvesting, and photocatalysis. In addition to their unique configurations, processability, and facile derivatization chemistries, AIE-active building blocks in scaffolds act as the origin of a new phase of matter. This work helps to motivate the exploration of “advisable aggregation effects” in emerging functions of material systems. © 2020 Elsevier Inc

Synthesis and self-assembly of a D_3h symmetric polycyclic aromatic hydrocarbon into a rigid 2D honeycomb network

C 3 symmetric hexa-peri-hexabenzocoronene carboxylic acid assembles into a rigid 2D honeycomb network at a solid–liquid interface.</p