A5084655324- Perovskite Materials and Applications
- Graphene research and applications
- Quantum Dots Synthesis And Properties
- Organic Light-Emitting Diodes Research
- 2D Materials and Applications
- Luminescence and Fluorescent Materials
- Biosensors and Analytical Detection
- Conducting polymers and applications
- Molecular Junctions and Nanostructures
- Solidification and crystal growth phenomena
- Advanced biosensing and bioanalysis techniques
- Nanopore and Nanochannel Transport Studies
- Organic Electronics and Photovoltaics
- Aluminum Alloy Microstructure Properties
- nanoparticles nucleation surface interactions
- Advanced Sensor and Energy Harvesting Materials
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Nanowire Synthesis and Applications
- Electrochemical sensors and biosensors
- Surface Modification and Superhydrophobicity
- Advancements in Battery Materials
- Carbon Nanotubes in Composites
- Molecular Sensors and Ion Detection
- Fluid Dynamics and Thin Films
Institute for Biomedical Engineering
2016-2024
Bioengineering (Switzerland)
2015-2024
ETH Zurich
2015-2024
National Taiwan University
2002-2023
Charles Humbert 8
2019-2021
Weatherford College
2021
Swiss Federal Laboratories for Materials Science and Technology
2018
École Polytechnique Fédérale de Lausanne
2018
Massachusetts Institute of Technology
2010-2016
Stanford University
2015
Metal-halide perovskites have rapidly emerged as one of the most promising materials 21st century, with many exciting properties and great potential for a broad range applications, from photovoltaics to optoelectronics photocatalysis. The ease which metal-halide can be synthesized in form brightly luminescent colloidal nanocrystals, well their tunable intriguing optical electronic properties, has attracted researchers different disciplines science technology. In last few years, there been...
Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as versatile photonic sources. Their processing and optoelectronic applications are hampered by the loss of colloidal stability structural integrity due to facile desorption surface capping molecules during isolation purification. To address this issue, herein, we propose a new ligand strategy utilizing common inexpensive long-chain zwitterionic such 3-(N,N-dimethyloctadecylammonio)propanesulfonate, resulting in much...
Understanding the pH-dependent behavior of graphene oxide (GO) aqueous solutions is important to production assembled GO or reduced films for electronic, optical, and biological applications. We have carried out a comparative experimental molecular dynamics (MD) simulation study uncover mechanisms behind aggregation surface activity at different pH values. At low pH, carboxyl groups are protonated such that sheets become less hydrophilic form aggregates. MD simulations further suggest...
Colloidal nanocrystals (NCs) of APbX3-type lead halide perovskites [A = Cs+, CH3NH3+ (methylammonium or MA+) CH(NH2)2+ (formamidinium FA+); X Cl-, Br-, I-] have recently emerged as highly versatile photonic sources for applications ranging from simple photoluminescence down-conversion (e.g., display backlighting) to light-emitting diodes. From the perspective spectral coverage, a formidable challenge facing use these materials is how obtain stable emissions in red and infrared regions...
We develop a theory to model the van der Waals interactions between liquid and graphene, including quantifying wetting behavior of graphene-coated surface. Molecular dynamics simulations contact angle measurements were also carried out test theory. show that graphene is only partially transparent predicted highest attainable water on surface 96\ifmmode^\circ\else\textdegree\fi{}. Our findings reveal more complex picture than what has been reported recently as complete ``wetting transparency.''
Solution-processed hybrid organic-inorganic lead halide perovskites are emerging as one of the most promising candidates for low-cost light-emitting diodes (LEDs). However, due to a small exciton binding energy, it is not yet possible achieve an efficient electroluminescence within blue wavelength region at room temperature, necessary full-spectrum light sources. Here, we demonstrate LEDs based on colloidal, quantum-confined 2D perovskites, with precisely controlled stacking down...
Understanding the solution-phase dispersion of pristine, unfunctionalized graphene is important for production conducting inks and top-down approaches to electronics. This process can also be used as a higher-quality alternative chemical vapor deposition. We have developed theoretical framework that utilizes molecular dynamics simulations kinetic theory colloid aggregation elucidate mechanism stabilization liquid-phase-exfoliated sheets in N-methylpyrrolidone (NMP), N,N'-dimethylformamide...
Field-effect transistor (FET) devices composed of a MoS2-graphene heterostructure can combine the advantages high carrier mobility in graphene with permanent band gap MoS2 for digital applications. Herein, we investigate electron transfer, photoluminescence, and gate-controlled transport such heterostructure. We show that junction is Schottky barrier, whose height be artificially controlled by gating or doping graphene. When applied gate voltage (or level) zero, photoexcited electron-hole...
Pure green light-emitting diodes (LEDs) are essential for realizing an ultrawide color gamut in next-generation displays, as is defined by the recommendation (Rec.) 2020 standard. However, because human eye more sensitive to spectral region, it not yet possible achieve ultrapure electroluminescence (EL) with a sufficiently narrow bandwidth that covers >95% of Rec. standard CIE 1931 space. Here, we demonstrate efficient, EL based on colloidal two-dimensional (2D) formamidinium lead bromide...
Abstract Intrinsically stretchable organic photovoltaics have emerged as a prominent candidate for the next-generation wearable power generators regarding their structural design flexibility, omnidirectional stretchability, and in-plane deformability. However, formulating strategies to fabricate intrinsically that exhibit mechanical robustness under both repetitive strain cycles high tensile strains remains challenging. Herein, we demonstrate high-performance with an initial conversion...
Graphene from two different preparative routes was successfully functionalized with 4-propargyloxybenzenediazonium tetrafluoroborate in order to study a subsequent attachment by click chemistry (1,3-dipolar azide–alkyne cycloaddition) of short chain polyethylene glycol terminal carboxylic end group (PEG-COOH). The reaction steps were studied FTIR and Raman spectroscopies, as well zeta-potential surface tension measurements. In the first route, pristine graphene surfactant dispersed stage...
Hybrid organic-inorganic and fully inorganic lead halide perovskite nanocrystals (NCs) have recently emerged as versatile solution-processable light-emitting light-harvesting optoelectronic materials. A particularly difficult challenge lies in warranting the practical utility of such semiconductor NCs red infrared spectral regions. In this context, all three archetypal A-site monocationic perovskites-CH3NH3PbI3, CH(NH2)2PbI3, CsPbI3-suffer from either chemical or thermodynamic instabilities...
The production of graphene with open band gaps for the manufacturing graphene-based electronic and optical devices requires synthesis methods to either control number layers enrich AB-stacked bilayer or trilayer extent functionalization monolayer graphene. Solution-phase dispersion is promising both create printable electronics nanocomposites. However, face common challenges, including controlling surface morphology, reducing turbostratic layering, enhancing stability. To address these...
Stacking up the filler material In composite materials, a strong or stiff is added to softer matrix create combined with better mechanical electrical properties. To minimize content, it needs be uniformly distributed in composite, which particularly challenging for nanoscale materials. Liu et al. alternately stacked sheets of graphene and polycarbonate make base composite. By further cutting stacking, 320 aligned layers were made very uniform distribution. Alternatively, initial stack could...
The dielectric constant, which defines the polarization of media, is a key quantity in condensed matter. It determines several electronic and optoelectronic properties important for plethora modern technologies from computer memory to field effect transistors communication circuits. Moreover, importance constant describing electromagnetic interactions through screening plays critical role understanding fundamental molecular interactions. Here, we show that despite its transcendence, does not...
Quantum dot (QD) light-emitting diodes (LEDs) are emerging as one of the most promising candidates for next-generation displays. However, their intrinsic light outcoupling efficiency remains considerably lower than organic counterpart, because it is not yet possible to control transition-dipole-moment (TDM) orientation in QD solids at device level. Here, using colloidal lead halide perovskite anisotropic nanocrystals (ANCs) a model system, we report directed self-assembly approach form...
Colloidal metal halide perovskite (MHP) nanocrystals (NCs) are an emerging class of fluorescent quantum dots (QDs) for next-generation optoelectronics. A great hurdle hindering practical applications, however, is their high lead content, where most attempts addressing the challenge in literature compromised material's optical performance or colloidal stability. Here, we present a postsynthetic approach that stabilizes lead-reduced MHP NCs through high-entropy alloying. Upon doping with...
Microfluidic paper-based analytical devices (µPADs) are indispensable tools for disease diagnostics. The integration of electronic components into µPADs enables new device functionalities and facilitates the development complex quantitative assays. Unfortunately, current electrode fabrication methods often hinder capillary flow, considerably restricting µPAD design architectures. Here, laser-induced graphenization is presented as an approach to fabricate porous electrodes embedded cellulose...
For many 2D materials, optical and Raman spectra are richly structured, convey information on a range of parameters including nanosheet size defect content. By contrast, the equivalent for h-BN relatively simple, with both absorption consisting single feature each, disclosing little information. Here, ability to size-select liquid-exfoliated nanosheets has allowed us comprehensively study dependence dimensions. We find extinction coefficient spectrum vary systematically lateral due presence...