Lin X. Chen

Bio: Lin X. Chen is an academic researcher from Argonne National Laboratory. The author has contributed to research in topics: Excited state & Absorption spectroscopy. The author has an hindex of 69, co-authored 319 publications receiving 17368 citations. Previous affiliations of Lin X. Chen include University of California, Berkeley & United States Department of Energy.

Polymer solar cells with enhanced fill factors

Abstract: New designs of donor polymers yield organic solar cells with fill factors approaching 80%, significantly higher than those of conventional cells. This enhanced performance is attributed to the close-packed and highly ordered structure of the polymers PTPD3T and PBT13T, which leads to efficient charge extraction and suppressed recombination.

Surface Restructuring of Nanoparticles: An Efficient Route for Ligand−Metal Oxide Crosstalk

Abstract: Surface modification of nanocrystalline metal oxide particles with enediol ligands was found to result in altered optical properties of nanoparticles. The surface modification results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites. The optical shift is correlated to the dipole moment of the Ti−ligand complexes at the particle surface and decreases with the ligand size. The binding was found to be exclusively characteristic of colloids in the nanocrystalline domain(<20 nm). X-ray near-edge structure measurements at Ti K edge indicate that in this size domain the surface Ti atoms adjust their coordination environment to form undercoordinated sites. These five-coordinated defect sites are the source of novel enhanced and selective reactivity of the nanoparticle toward bidentate ligand binding as observed using IR spectroscopy. Enediol ligands have the optimal geometry for chelating surface Ti atoms, resulting in a five-membered ring coordination complex and restored si...

Effects of Additives on the Morphology of Solution Phase Aggregates Formed by Active Layer Components of High-Efficiency Organic Solar Cells

Abstract: Processing additives are used in organic photovoltaic systems to optimize the active layer film morphology. However, the actual mechanism is not well understood. Using X-ray scattering techniques, we analyze the effects of an additive diiodooctane (DIO) on the aggregation of a high-efficiency donor polymer PTB7 and an acceptor molecule PC71BM under solar cell processing conditions. We conclude that DIO selectively dissolves PC71BM aggregates, allowing their intercalation into PTB7 domains, thereby optimizing both the domain size and the PTB7–PC71BM interface.

Using coherence to enhance function in chemical and biophysical systems

Abstract: Coherence phenomena arise from interference, or the addition, of wave-like amplitudes with fixed phase differences. Although coherence has been shown to yield transformative ways for improving function, advances have been confined to pristine matter and coherence was considered fragile. However, recent evidence of coherence in chemical and biological systems suggests that the phenomena are robust and can survive in the face of disorder and noise. Here we survey the state of recent discoveries, present viewpoints that suggest that coherence can be used in complex chemical systems, and discuss the role of coherence as a design element in realizing function.

Influence of iron doping on tetravalent nickel content in catalytic oxygen evolving films

Abstract: Iron doping of nickel oxide films results in enhanced activity for promoting the oxygen evolution reaction (OER). Whereas this enhanced activity has been ascribed to a unique iron site within the nickel oxide matrix, we show here that Fe doping influences the Ni valency. The percent of Fe3+ doping promotes the formation of formal Ni4+, which in turn directly correlates with an enhanced activity of the catalyst in promoting OER. The role of Fe3+ is consistent with its behavior as a superior Lewis acid.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Magnetic nanoparticles: Synthesis, protection, functionalization, and application

Abstract: This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.

Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review.

Abstract: The lithium metal battery is strongly considered to be one of the most promising candidates for high-energy-density energy storage devices in our modern and technology-based society. However, uncontrollable lithium dendrite growth induces poor cycling efficiency and severe safety concerns, dragging lithium metal batteries out of practical applications. This review presents a comprehensive overview of the lithium metal anode and its dendritic lithium growth. First, the working principles and technical challenges of a lithium metal anode are underscored. Specific attention is paid to the mechanistic understandings and quantitative models for solid electrolyte interphase (SEI) formation, lithium dendrite nucleation, and growth. On the basis of previous theoretical understanding and analysis, recently proposed strategies to suppress dendrite growth of lithium metal anode and some other metal anodes are reviewed. A section dedicated to the potential of full-cell lithium metal batteries for practical applicatio...