Designing new hole‐transporting materials (HTMs) with desired chemical, electrical, and electronic properties is critical to realize efficient and stable inverted perovskite solar cells (PVSCs) with ...a p–i–n structure. Herein, the synthesis of a novel 3D small molecule named TPE‐S and its application as an HTM in PVSCs are shown. The all‐inorganic inverted PVSCs made using TPE‐S, processed without any dopant or post‐treatment, are highly efficient and stable. Compared to control devices based on the commonly used HTM, PEDOT:PSS, devices based on TPE‐S exhibit improved optoelectronic properties, more favorable interfacial energetics, and reduced recombination due to an improved trap passivation effect. As a result, the all‐inorganic CsPbI2Br PVSCs based on TPE‐S demonstrate a remarkable efficiency of 15.4% along with excellent stability, which is the one of the highest reported values for inverted all‐inorganic PVSCs. Meanwhile, the TPE‐S layer can also be generally used to improve the performance of organic/inorganic hybrid inverted PVSCs, which show an outstanding power conversation efficiency of 21.0%, approaching the highest reported efficiency for inverted PVSCs. This work highlights the great potential of TPE‐S as a simple and general dopant‐free HTM for different types of high‐performance PVSCs.
A new S‐atom‐containing small molecule (TPE‐S) is introduced as a dopant‐free hole‐transporting layer in all‐inorganic and organic/inorganic hybrid perovskite solar cells (PVSCs) with a p–i–n inverted structure, leading to improved power conversion efficiencies of 15.4% and 21%, respectively. In addition, these devices also show enhanced photostability, with performance comparable to state‐of‐the‐art PVSCs based on the conventional n–i–p structure.
Two new n-channel polymeric semiconductors for organic thin-film transistors (TFTs) based on electron-depleted perylene- (PDI) and naphthalene-dicarboxyimide (NDI) polymerized with dithiophene are ...reported: poly{N,N′-bis(2-octyldodecyl)-1,4,5,8-naphthalene dicarboximide-2,6-diyl-alt-5,5′-(2,2′-bithiophene)}, P(NDI2OD-T2), and poly{N,N′-bis(2-octyldodecyl)-3,4,9,10-perylenedicarboximide-(1,7&1,6)-diyl-alt-5,5′-(2,2′-bithiophene)}, P(PDI2OD-T2). Polymer regioregularity and electronic structure strongly depend on the rylene co-monomer. The use of NDI enables a regioregular and high-molecular-weight polymer with greatly stabilized electron transport in ambient. Unoptimized P(NDI2OD-T2)-based TFTs exhibit good electron mobilities μe ≈ 0.04 (0.01) cm2/V·s in vacuum (ambient after 16 weeks) vs μe ≈ 0.003 (2 × 10−4) cm2/V·s in vacuum (ambient after 1.5 week) for P(PDI2OD-T2) and on−off current modulation I on:I off > 106.
One important feature of organic semiconductors is their solution processability, which allows researchers to tune their aggregation states in solution and solid states and to control the processing ...conditions to reach desirable electronic and optoelectronic properties. Temperature is one of the most important processing parameters of organic semiconductors and has been studied extensively particularly for those conjugated small‐ and macro‐ molecules with strong temperature‐dependent aggregation properties. This minireview summarizes the temperature‐induced aggregation behaviors of organic semiconductors in solution, during solution casting and upon thermal annealing post‐treatment of solid‐state thin films. The influences of different aggregation states on the optoelectronic properties, in particular the photovoltaic properties, are discussed. The conclusions in this work will provide a rational guide to precisely control the aggregation states of organic semiconductors to fabricate high‐performance optoelectronic devices.
Temperature plays a vital role in determining the aggregation behavior of organic semiconductors in solution, during solution casting and in solid thin films, consequently it has an impact on optoelectronic properties.
The effects of number of graphene layers (n) and size of multilayer graphene sheets on thermal conductivities (TCs) of their epoxy composites are investigated. Molecular dynamics simulations show ...that the in-plane TCs of graphene sheets and the TCs across the graphene/epoxy interface simultaneously increase with increasing n. However, such higher TCs of multilayer graphene sheets will not translate into higher TCs of bulk composites unless they have large lateral sizes to maintain their aspect ratios comparable to the monolayer counterparts. The benefits of using large, multilayer graphene sheets are confirmed by experiments, showing that the composites made from graphite nanoplatelets (n > 10) with over 30 μm in diameter deliver a TC of ∼1.5 W m–1 K–1 at only 2.8 vol %, consistently higher than those containing monolayer or few-layer graphene at the same graphene loading. Our findings offer a guideline to use cost-effective multilayer graphene as conductive fillers for various thermal management applications.
Well‐controlled nanostructures and a high fraction of Sn/Li2O interface are critical to enhance the coulombic efficiency and cyclic performance of SnO2‐based electrodes for lithium‐ion batteries ...(LIBs). Polydopamine (PDA)‐coated SnO2 nanocrystals, composed of hundreds of PDA‐coated “corn‐like” SnO2 nanoparticles (diameter ca. 5 nm) decorated along a “cob”, addressed the irreversibility issue of SnO2‐based electrodes. The PDA‐coated SnO2 were crafted by capitalizing on rationally designed bottlebrush‐like hydroxypropyl cellulose‐graft‐poly (acrylic acid) (HPC‐g‐PAA) as a template and was coated with PDA to construct a passivating solid‐electrolyte interphase (SEI) layer. In combination, the corn‐like nanostructure and the protective PDA coating contributed to a PDA‐coated SnO2 electrode with excellent rate capability, superior long‐term stability over 300 cycles, and high Sn→SnO2 reversibility.
Corn‐on‐the‐cob: A porous electrode material comprising SnO2 nanocrystals coated with a protective polydopamine thin layer was prepared. The electrode exhibits excellent rate capability and long‐term stability for more than 300 cycles at test current densities from 160 to 1500 mA g−1. Sn→SnO2 reversibility was observed with capacities approaching the theoretical capacity of 1494 mA h g−1 at a low current density of 160 mA g−1.
In this work, an effectual strategy of constructing polar small molecule acceptors (SMAs) to promote fill factor (FF) of nonfullerene polymer solar cells (PSCs) is first reported. Three asymmetrical ...SMAs of IDT6CN, IDT6CN‐Th, and IDT6CN‐M, which own large dipole moments, are designed and synthesized. The PSCs based on three polar SMAs exhibit apparently higher FFs compared with their symmetrical analogues. The asymmetrical design strategy accompanied with side chain and end group engineering makes IDT6CN‐Th‐ and IDT6CN‐M‐based nonfullerene PSCs achieve high power conversion efficiency with FFs approaching 77%.
The asymmetrical acceptors IDT6CN‐Th and IDT6CN‐M with a large dipole moment outside the molecular backbone show strong π–π stacking in the out‐of‐plane direction. Polymer solar cells based on IDT6CN‐Th and IDT6CN‐M achieve high efficiencies of 10.41% and 11.20% with fill factors (FFs) of 76.72% and 76.83%, respectively, indicating that constructing polar small‐molecule acceptors to enhance the FF is an effective strategy.
Many metal–organic cages (MOCs) and a few hydrogen‐bonded organic cages (HOCs) have been investigated, but little is reported about cooperative self‐assembly of MOCs and HOCs. Herein, we describe an ...unprecedented MOC&HOC co‐crystal composed of tetrahedral Ti4L6 (L=embonate) cages and in‐situ‐generated (NH3)4(TIPA)4 (TIPA=tris(4‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)amine) cages. Chiral transfer is observed from the enantiopure Ti4L6 cage to enantiopure (NH3)4(TIPA)4 cage. Two homochiral supramolecular frameworks with opposite handedness (PTC‐235(Δ) and PTC‐235(Λ)) are formed. Such MOC&HOC co‐crystal features high stability in water and other solvents, affording single‐crystal‐to‐single‐crystal transformation to trap CH3CN molecules and identify disordered NH4+ cations. A tablet pressing method is developed to test the third‐order nonlinear optical property of KBr‐based PTC‐235 thin film. Such a thin film exhibits an excellent optical limiting effect.
The supramolecular self‐assembly between metal–organic cages (MOCs) and hydrogen‐bonded organic cages (HOCs) is realized in an MOC&HOC co‐crystal composed of tetrahedral Ti4L6 cages and (NH3)4(TIPA)4 cages generated in situ. The MOC&HOC co‐crystal thin film exhibits an excellent optical limiting effect.
High energy density LiNi0.8Co0.1Mn0.1O2 (NCM811)/Li metal batteries exhibit poor cycling due to the inferior structure stability of NCM811. Herein, a hierarchical cathode electrolyte interphase (CEI) ...with highly dense, resistive and protective properties is in-situ growth on NCM811 by decomposition reaction of lithium difluoro(oxalato)borate (LiDFOB). The hierarchical CEI presents special two-layered structure, where the inner layer is rich in LiF and outer layer mainly contains organic components such as LixBOyFz. The highly resistive inner layer can effectively prevent the NCM811 from further reacting with electrolyte and reduce the accumulation of organic products in outer layer during long cycling. Additionally, the LiDFOB can also induce the uniform deposition of Li ion, increase the Li plating/striping coulombic efficiency and inhibit the growth of Li dendrites. The NCM811/Li battery using LiDFOB presents a greatly improved rate and cycling performance. For instance, the NCM811/Li metal batteries using LiDFOB and LiPF6 based electrolyte delivers a specific capacity of 127.5 and 80.5 mAh g-1 at 10C, respectively and their capacity retentions are 69.8% and 17.1% after 400 cycles. The LiDFOB is a promising lithium salt for advanced high energy density NCM811/Li metal battery.
The LiDFOB can be oxidatively decomposed on the NCM811 cathode to form hierarchical CEI, which has LiF-rich inner layer and organic composition-rich outer layer. The robust CEI can protect the NCM811 from over-reaction with electrolyte and over-growth of impedance during cycling. The LiDFOB electrolyte can also induce the uniform deposition of Li ion on the anode. Display omitted
•LiDFOB is beneficial for LiNi0.8Co0.1Mn0.1(NCM811)/Li batteries.•Hierarchical cathode electrolyte interphase is in-situ formed on NCM811 particles.•Cathode electrolyte interphase presents special and robust two-layer structure.•LiDFOB can induce uniform deposition of Li ion to suppress Li dendrite growth.
Aiming at the limitations of existing fire detection technology and the multi-dimensional challenge of tourist satisfaction analysis, this study proposes a series of innovative methods and models. ...Regarding fire detection, Depth Separable Convolution (DSC) and multi-scale detection structure are introduced to improve the You Only Look Once version 3 (YOLOv3) model. Moreover, the DSC-Anchor-Isoft-Non Maximum Suppression-YOLO (DAI-YOLO) model is implemented for the fire detection of scenic spots. The experimental results show that the precision, recall, and average precision of the DAI-YOLO model are 92.1%, 84.2%, and 84.6%, respectively, compared with other models, a minimum increase of 4.1%, 8.8%, and 6.0%, with higher detection accuracy and performance. Based on the analysis of tourist satisfaction, a comprehensive index system is constructed using the grounded theory of text mining, and emotion analysis is integrated into the satisfaction evaluation to reveal tourists' evaluation of scenic spots more comprehensively. According to the analysis, the environmental factor receives the highest satisfaction rating, reaching a positive rate of 98.78%. However, the satisfaction evaluation of scenic spot management is relatively low, accounting for 6.06% of the negative evaluation. The importance-satisfaction analysis reveals that the key factors affecting tourist satisfaction are traffic level, scenic spot tickets, and service. The results of this study provide valuable reference for the managers and researchers of scenic spots and are expected to contribute to the construction of a safer and more satisfying tourism experience.
A unique family of chiral peraza N6‐macrocyclic ligands, which are conformationally rigid and have a tunable saddle‐shaped cavity, is described. Utilizing their manganese(I) complexes, the first ...example of earth‐abundant transition metal‐catalyzed asymmetric formal anti‐Markovnikov hydroamination of allylic alcohols was realized, providing a practical access to synthetically important chiral γ‐amino alcohols in excellent yields and enantioselectivities (up to 99 % yield and 98 % ee). The single‐crystal structure of a MnI complex indicates that the manganese atom coordinates with the chiral dialkylamine moiety in a bidentate fashion. Further DFT calculations revealed that five of the six nitrogen atoms in the ligand were engaged in multiple noncovalent interactions with Mn, an isopropanol molecule, and a β‐amino ketone intermediate via coordination, hydrogen bonding, and/or CH⋅⋅⋅π interactions in the transition state, showing a remarkable role of the macrocyclic framework.
The first example of Mn‐catalyzed asymmetric formal anti‐Markovnikov hydroamination of allylic alcohols is described by using a chiral peraza N6‐macrocyclic ligand. DFT calculations revealed that multiple noncovalent interactions existed among the ligand, solvent, and substrate in the transition states, showing a remarkable macrocyclic ligand effect.
PDF
