A5057665432- Liquid Crystal Research Advancements
- Conducting polymers and applications
- Perovskite Materials and Applications
- Organic Electronics and Photovoltaics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Covalent Organic Framework Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Molecular spectroscopy and chirality
- Luminescence and Fluorescent Materials
- Photonic Crystals and Applications
- Advanced Materials and Mechanics
- Plant Reproductive Biology
- Organic Light-Emitting Diodes Research
- Quantum Dots Synthesis And Properties
- Surfactants and Colloidal Systems
- Block Copolymer Self-Assembly
- Advanced Battery Materials and Technologies
- Advanced Polymer Synthesis and Characterization
- Supramolecular Self-Assembly in Materials
- Advanced Sensor and Energy Harvesting Materials
- Synthesis and Properties of Aromatic Compounds
- Nonlinear Dynamics and Pattern Formation
- Material Dynamics and Properties
- Pickering emulsions and particle stabilization
Lawrence Berkeley National Laboratory
2016-2025
Institute of Acoustics
2023-2025
Chinese Academy of Sciences
2023-2025
Berkeley College
2016-2024
Henan University of Science and Technology
2021-2024
University of Electronic Science and Technology of China
2019-2024
University of Chinese Academy of Sciences
2023-2024
North China University of Water Resources and Electric Power
2023
Université Paris-Saclay
2023
Soochow University
2023
A key challenge in the field of electrochemical carbon dioxide reduction is design catalytic materials featuring high product selectivity, stability, and a composition earth-abundant elements. In this work, we introduce thin films nanosized metal-organic frameworks (MOFs) as atomically defined nanoscopic that function catalysts for efficient selective to monoxide aqueous electrolytes. Detailed examination cobalt-porphyrin MOF, Al2(OH)2TCPP-Co (TCPP-H2 =...
A three-dimensional covalent organic framework (COF-505) constructed from helical threads, designed to be mutually weaving at regular intervals, has been synthesized by imine condensation reactions of aldehyde functionalized copper(I)-bisphenanthroline tetrafluoroborate, Cu(PDB)2(BF4), and benzidine (BZ). The copper centers are topologically independent the within COF structure serve as templates for bringing threads into a woven pattern rather than more commonly observed parallel...
The electronic character of porphyrin active sites for electrocatalytic reduction CO2 to CO in a two-dimensional covalent organic framework (COF) was tuned by modification the reticular structure. Efficient charge transport along COF backbone promotes connectivity between remote functional groups and enables modulation catalytic properties system. A series oriented thin films these COFs found reduce at low overpotential (550 mV) with high selectivity (faradaic efficiency 87%) current...
The first unsubstituted olefin-linked covalent organic framework, termed COF-701, was made by linking 2,4,6-trimethyl-1,3,5-triazine (TMT) and 4,4′-biphenyldicarbaldehyde (BPDA) through Aldol condensation. Formation of the olefin (-CH═CH-) linkage upon reticulation is confirmed Fourier transform infrared (FT-IR) spectroscopy solid-state 13C cross-polarization magic angle spinning (CP-MAS) NMR framework its 13C-isotope-labeled analogue. COF-701 found to be porous (1715 m2 g–1) retain...
The precise control of stoichiometric balance and ionic defects on the surface solution-processed perovskite is critical to performance stability solar cells (pero-SCs). Here, we introduce a low-cost stable conjugated donor polymer (PTQ10) as interfacial layer in planar n–i–p structured pero-SCs. was applied intermediate phase before thermal annealing. This treatment significantly reduced loss organic cation during Importantly, kinetics conversion influenced, crystal showed more preferential...
Atmospheric moisture is a ubiquitous water resource available at any time and place, making it attractive to develop materials for harvesting from air address the imminent shortage crisis. In this context, we have been exploring applicability of covalent organic frameworks (COFs) report here new porous, two-dimensional imine-linked COF with voided square grid topology, termed COF-432. Unlike other reported COFs, COF-432 meets requirements desired in that exhibits an S-shaped sorption...
A-sites join the band edge The of hybrid organic-inorganic perovskites, which have general formula ABX 3 , is mainly controlled by inorganic X anions (such as chloride) and B cation lead). Organic A-site cations usually only exert indirect structural effects because their electronic levels lie far from edge. Xue et al. show that with large π-conjugated structures can interact frontier molecular orbitals. A surface layer ethylammonium pyrene, had an optimal intercalation distance, increased...
Abstract Multicomponent nanocrystal superlattices represent an interesting class of material that derives emergent properties from mesoscale structure, yet their programmability can be limited by the alkyl-chain-based ligands decorating surfaces constituent nanocrystals. Polymeric offer distinct advantages, as they allow for more precise tuning effective size and ‘interaction softness’ through changes to polymer’s molecular weight, chemical nature, architecture, persistence length...
Developing synthetic methodology to crystallize extended covalent structures has been an important pursuit of reticular chemistry. Here, we report a homogeneous route for imine organic frameworks (COFs) where crystallites emerge from clear solutions without forming amorphous polyimine precipitates. The key feature this is the utilization tert-butyloxycarbonyl group protected amine building blocks, which are deprotected in situ and gradually nucleate crystalline framework. We demonstrate...
Sn(II)-based halide perovskite semiconductor materials are promising for a variety of electronics and optoelectronics applications but suffer from poor intrinsic stability. Here, we report the synthesis characterization stable Sn (II)-based two-dimensional featuring π-conjugated oligothiophene ligand, namely (4Tm)2SnI4, where 4Tm is 2-(3″',4'-dimethyl-[2,2':5',2″:5″,2″'-quaterthiophen]-5-yl)ethan-1-ammonium. The conjugated ligands facilitate formation micrometer-size large grains, improve...
Abstract Hybrid lead halide perovskites have emerged as high-performance photovoltaic materials with their extraordinary optoelectronic properties. In particular, the remarkable device efficiency is strongly influenced by perovskite crystallinity and film morphology. Here, we investigate crystallisation kinetics growth mechanism in real time from liquid precursor continually to final uniform film. We utilize some advanced situ characterisation techniques including synchrotron-based grazing...
Periodically eclipsed π-stacking columns in two-dimensional covalent organic frameworks (2D COFs) could function as direct channel paths for charge carrier transport. Incorporating a well-defined 2D COF into electronic devices, however, is still challenge. Herein, we have reported the solvothermal synthesis of COFTFPy-PPDA film on single-layer graphene (SLG), which was constructed via imine-type linkage by employing 1,3,6,8-tetrakis(p- formylphenyl)pyrene (TFPy) and p-phenylenediamine (PPDA)...
2D covalent organic frameworks (COFs) with flexible urea linkages have been synthesized by condensation of 1,3,5-triformylphloroglucinol (TFP) 1,4-phenylenediurea (BDU) or 1,1′-(3,3′-dimethyl-[1,1′-biphenyl]-4,4′-diyl)diurea (DMBDU). The resulting COF-117 and COF-118 undergo reversible structural dynamics within their layers, in response to inclusion removal guest molecules, emanating from C—N bond rotation interlayer hydrogen-bonding interactions. These compounds are the first urea-linked...
Resonant x-ray scattering shows that the bulk structure of twist-bend liquid crystal phase, recently discovered in bent molecular dimers, has spatial periodicity without electron density modulation, indicating a lattice-free heliconical nematic precession orientation helical glide symmetry. In situ study helix texture for dimer CB7CB an elastically-confined temperature-dependent minimum pitch, but remarkable elastic softness pitch response to dilative stresses. Scattering from is not...
Two medium-bandgap p-type organic small molecules H21 and H22 with an alkylsily-thienyl conjugated side chain on benzo[1,2-b:4,5-b']dithiophene central units are synthesized used as donors in all-small-molecule solar cells (SM-OSCs) a narrow-bandgap n-type molecule 2,2'-((2Z,2'Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC) the acceptor. In comparison to 3-ethyl...
Abstract Demonstrated in this work is a simple random ternary copolymerization strategy to synthesize series of polymer acceptors, PTPBT‐ET x , by polymerizing small‐molecule acceptor unit modified from Y6 with thiophene connecting and controlled amount an 3‐ethylesterthiophene (ET) unit. Compared PTPBT only Y6‐like units units, (where represents the molar ratio ET unit) incorporated copolymers show up‐shifted LUMO energy levels, increased electron mobilities, improved blend morphologies...
Abstract Electroluminescence efficiencies and stabilities of quasi-two-dimensional halide perovskites are restricted by the formation multiple-quantum-well structures with broad uncontrollable phase distributions. Here, we report a ligand design strategy to substantially suppress diffusion-limited disproportionation, thereby enabling better control. We demonstrate that extending π-conjugation length increasing cross-sectional area enables perovskite thin films dramatically suppressed ion...
Abstract Surface passivation is an effective way to boost the efficiency and stability of perovskite solar cells (PSCs). However, a key challenge faced by most strategies reducing interface charge recombination without imposing energy barriers extraction. Here, novel multifunctional semiconducting organic ammonium cationic modifier inserted between light‐harvesting film hole‐transporting layer reported. It shown that conjugated cations can directly extract holes from efficiently,...
Abstract Sequentially deposited organic solar cells (SD‐OSCs) have attracted great attention owing to their ability in achieving a more favorable, vertically phase‐separated morphology avoid the accumulation of counter charges at absorber/transporting layer interfaces. However, processing SD‐OSCs is still quite challenging preventing penetration small‐molecule acceptors into polymer donor via erosion or swelling. Herein, solid additives (SAs) with varied electrostatic potential distributions...
We have structurally characterized the liquid crystal (LC) phase that can appear as an intermediate state when a dielectric nematic, having polar disorder of its molecular dipoles, transitions to almost perfectly polar-ordered ferroelectric nematic. This phase, which fills 100-y-old void in taxonomy smectic LCs and we term "smectic ZA," is antiferroelectric, with nematic director polarization oriented parallel layer planes, alternating sign from 180 Å period. A Landau free energy, originally...
The influences of various processing parameters and polymer molecular weight on the morphology properties poly[(5,6‐difluoro‐2,1,3‐benzothiadiazol‐4,7‐diyl)‐alt‐(3,3′′′‐di(2‐octyldodecyl) 2,2′;5′,2″;5″,2′′′‐quaterthiophen‐5,5′′′‐diyl)] (PffBT4T‐2OD)‐based solar cells (PSCs) are investigated. High spin rate/high temperature conditions found to significantly reduce crystallinity change backbone orientation from face‐on edge‐on. Most surprisingly, it is that median domain sizes...