Tao Yang

Bio: Tao Yang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Quantum dot & Quantum dot laser. The author has an hindex of 26, co-authored 254 publications receiving 2592 citations. Previous affiliations of Tao Yang include Lanzhou University of Technology & Hebei Normal University.

A nonfullerene acceptor with a 1000 nm absorption edge enables ternary organic solar cells with improved optical and morphological properties and efficiencies over 15

Abstract: Ternary organic solar cells (OSCs) have shown tremendous potential in improving the photovoltaic performance of single-junction OSCs. Here, a series of ternary OSCs are fabricated with PM7:ITC-2Cl as the host system and an ultra-low bandgap acceptor named IXIC-4Cl that has an absorption edge reaching 1000 nm as the third component. The optimal ternary OSC shows a power conversion efficiency (PCE) of 15.37%, which is significantly higher than those of the binary counterparts based on PM7:ITC-2Cl (13.72%) or PM7:IXIC-4Cl (12.01%). The excellent PCE is mainly attributed to the increased short-circuit current (JSC), which mainly arises from the complementary absorption of the third component and thus the overall broadened absorption profile. In addition, the addition of IXIC-4Cl into the PM7:ITC-2Cl binary system suppresses bimolecular recombination, improves charge dissociation and the collection efficiency, balances charge transport and reduces the domain size, which are responsible for the enhanced JSC. Noticeably, the optimized ternary device shows a PCE over 15% with a quite small energy loss, which are the best results for ternary OSCs to date. These results offer more insight into the role of an ultra-low bandgap non-fullerene acceptor as the third component in promoting the device performance of ternary OSCs.

Exploring Lead-Free Hybrid Double Perovskite Crystals of (BA) 2 CsAgBiBr 7 with Large Mobility-Lifetime Product toward X-Ray Detection.

Abstract: Halide double perovskites have recently bloomed as the green candidates for optoelectronic applications, such as X-ray detection. Despite great efforts, the exploration of promising organic-inorganic hybrid double perovskites toward X-ray detection remains unsuccessful. Now, single crystals of the lead-free hybrid double perovskite, (BA)2 CsAgBiBr7 (BA+ is n-butylammonium), featuring the unique 2D multilayered quantum-confined motif, enable quite large μτ (mobility-lifetime) product up to 1.21×10-3 cm2 V-1 . This figure-of-merit realized in 2D hybrid double perovskites is unprecedented and comparable with that of CH3 NH3 PbI3 wafers. (BA)2 CsAgBiBr7 crystals also exhibit other intriguing attributes for X-ray detection, including high bulk resistivity, low density of defects and traps, and large X-ray attenuation coefficient. Consequently, a vertical-structure crystal device under X-ray source yields a superior sensitivity of 4.2 μC Gyair-1 cm-2 .

Synthesis and magnetic properties of e-cobalt nanoparticles

Abstract: Monodisperse cobalt nanoparticles are synthesized via a high-temperature thermal decomposition method in the presence of oleic acid and triphenylphosphine. The as-synthesized nanoparticles are stable against further deep oxidation when they are kept in heptane .C7H16/. Time-dependent XPS studies indicate that oxidation of the as-synthesized cobalt nanoparticles in air is slow. The valence change of cobalt from the nanoparticle sample is not observed after it is kept in heptane under air for 90 days. The cobalt nanoparticles have a b-manganese-type structure (also called e-Co). Annealing the nanoparticles at 500 ◦ C under Ar .95%/ +H 2 .5%/ converts these particles from e-Co to fcc-Co. Two-dimensional and three-dimensional self-assembled superlattices of the passivated cobalt nanoparticles are formed by slow evaporation of the carrier solvent. The magnetic properties of the cobalt nanoparticles in different forms are compared, which provides helpful information on the magnetostatic interaction of the nanoparticles. Copyright  2004 John Wiley & Sons, Ltd.

Self-assembly and magnetic properties of cobalt nanoparticles

Abstract: Two- and three-dimensional superlattices of passivated cobalt nanoparticles were formed by a self-assembly technique. The size and stabilization of the cobalt nanoparticles are controlled by using the combination of oleic acid and triphenylphosphine. The cobalt nanoparticles are stable for at least 90 days without oxidation at room temperature under ambient conditions. The magnetic properties of the cobalt nanoparticles in different forms are compared, which provides helpful information on the magnetostatic interaction of the nanoparticles.

Fundamentals and Catalytic Applications of CeO2-Based Materials

Abstract: Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

Observation of Single Colloidal Platinum Nanocrystal Growth Trajectories

Abstract: It is conventionally assumed that the growth of monodisperse colloidal nanocrystals requires a temporally discrete nucleation followed by monomer attachment onto the existing nuclei. However, recent studies have reported violations of this classical growth model, and have suggested that inter-particle interactions are also involved during the growth. Mechanisms of nanocrystal growth still remain controversial. Using in situ transmission electron microscopy, we show that platinum nanocrystals can grow either by monomer attachment from solution onto the existing particles or by coalescence between the particles. Surprisingly, an initially broad size distribution of the nanocrystals can spontaneously narrow. We suggest that nanocrystals take different pathways of growth based on their size- and morphology-dependent internal energies. These observations are expected to be highly relevant for other nanocrystal systems.

Surface enhanced fluorescence

Abstract: Fluorescence is widely used in optical devices, microscopy imaging, biology, medical research and diagnosis. Improving fluorescence sensitivity, all the way to the limit of single-molecular detection needed in many applications, remains a great challenge. The technique of surface enhanced fluorescence (SEF) is based upon the design of surfaces in the vicinity of the emitter. SEF yields an overall improvement in the fluorescence detection efficiency through modification and control of the local electromagnetic environment of the emitter. Near-field coupling between the emitter and surface modes plays a crucial role in SEF. In particular, plasmonic surfaces with localized and propagating surface plasmons are efficient SEF substrates. Recent progress in tailoring surfaces at the nanometre scale extends greatly the realm of SEF applications. This review focuses on the recent advances in the different mechanisms involved in SEF, in each case highlighting the most relevant applications.

Over 17% efficiency ternary organic solar cells enabled by two non-fullerene acceptors working in an alloy-like model

Abstract: Nowadays, organic solar cells (OSCs) with Y6 and its derivatives as electron acceptors provide the highest efficiencies among the studied binary OSCs. To further improve the performances of OSCs, the fabrication of ternary OSCs (TOSCs) is a convenient strategy. Essentially, morphology control and the trade-off between voltage and photocurrent are the main critical issues in TOSCs. Herein, we address these problems by constructing TOSCs where an alloy-like composite is formed between Y6 and a newly designed derivative, BTP-M. Employing an electron-pushing methyl substituent as a replacement for the electron-withdrawing F atoms on Y6, BTP-M shows higher energy levels and lower crystallinity than Y6. As a result, the obtained Y6:BTP-M alloy can simultaneously optimize energy levels to reduce energy loss as well as the morphologies of the active layers to favor photocurrent generation, leading to an enhanced open-circuit voltage (Voc) of 0.875 V together with a larger short-circuit current density (Jsc) of 26.56 mA cm−2 for TOSCs based on the polymer donor PM6 and Y6:BTP-M acceptor alloy. Consequently, a best efficiency of 17.03% is achieved for the corresponding TOSCs, which is among the best values for single-junction OSCs. In addition, our TOSCs also exhibit good thickness tolerance, and can reach 14.23% efficiency even though the active layer is as thick as 300 nm.

Mesoporous materials for clean energy technologies

Abstract: Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity.