Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

Here, we present a review of the antibacterial effects of silver nanomaterials, including proposed antibacterial mechanisms and possible toxicity to higher organisms. For purpose of this review, silver nanomaterials include silver nanoparticles, stabilized silver salts, silver–dendrimer, polymer and metal oxide composites, and silver-impregnated zeolite and activated carbon materials. While there is some evidence that silver nanoparticles can directly damage bacteria cell membranes, silver nanomaterials appear to exert bacteriocidal activity predominantly through release of silver ions followed (individually or in combination) by increased membrane permeability, loss of the proton motive force, inducing de-energization of the cells and efflux of phosphate, leakage of cellular content, and disruption DNA replication. Eukaryotic cells could be similarly impacted by most of these mechanisms and, indeed, a small but growing body of literature supports this concern. Most antimicrobial studies are performed in simple aquatic media or cell culture media without proper characterization of silver nanomaterial stability (aggregation, dissolution, and re-precipitation). Silver nanoparticle stability is governed by particle size, shape, and capping agents as well as solution pH, ionic strength, specific ions and ligands, and organic macromolecules—all of which influence silver nanoparticle stability and bioavailability. Although none of the studies reviewed definitively proved any immediate impacts to human health or the environment by a silver nanomaterial containing product, the entirety of the science reviewed suggests some caution and further research are warranted given the already widespread and rapidly growing use of silver nanomaterials.

https://link.springer.com/content/pdf/10.1007%2Fs11051-010-9900-y.pdf

A review of the antibacterial effects of silver nanomaterials and potential implications for human health and the environment

A review was presented to demonstrate a historical description of the synthesis of light-emitting conjugated polymers for applications in electroluminescent devices. Electroluminescence (EL) was first reported in poly(para-phenylene vinylene) (PPV) in 1990 and researchers continued to make significant efforts to develop conjugated materials as the active units in light-emitting devices (LED) to be used in display applications. Conjugated oligomers were used as luminescent materials and as models for conjugated polymers in the review. Oligomers were used to demonstrate a structure and property relationship to determine a key polymer property or to demonstrate a technique that was to be applied to polymers. The review focused on demonstrating the way polymer structures were made and the way their properties were controlled by intelligent and rational and synthetic design.

Synthesis of Light-Emitting Conjugated Polymers for Applications in Electroluminescent Devices

Non-fullerene acceptors (NFAs) are currently a major focus of research in the development of bulk-heterojunction organic solar cells (OSCs). In contrast to the widely used fullerene acceptors (FAs), the optical properties and electronic energy levels of NFAs can be readily tuned. NFA-based OSCs can also achieve greater thermal stability and photochemical stability, as well as longer device lifetimes, than their FA-based counterparts. Historically, the performance of NFA OSCs has lagged behind that of fullerene devices. However, recent developments have led to a rapid increase in power conversion efficiencies for NFA OSCs, with values now exceeding 13%, demonstrating the viability of using NFAs to replace FAs in next-generation high-performance OSCs. This Review discusses the important work that has led to this remarkable progress, focusing on the two most promising NFA classes to date: rylene diimide-based materials and materials based on fused aromatic cores with strong electron-accepting end groups. The key structure–property relationships, donor–acceptor matching criteria and aspects of device physics are discussed. Finally, we consider the remaining challenges and promising future directions for the NFA OSCs field. Non-fullerene acceptors have been widely used in organic solar cells over the past 3 years. This Review focuses on the two most promising classes of non-fullerene acceptors — rylene diimide-based materials and fused-ring electron acceptors — and discusses structure–property relationships, donor– acceptor matching criteria and device physics, as well as future research directions for the field.

Non-fullerene acceptors for organic solar cells

White organic light-emitting devices (WOLEDs) have advanced over the last twelve years to the extent that these devices are now being considered as efficient solid-state lighting sources. Initially, WOLEDs were targeted towards display applications for use primarily as liquid-crystal display backlights. Now, their power efficiencies have surpassed those of incandescent sources due to improvements in device architectures, synthesis of novel materials, and the incorporation of electrophosphorescent emitters. This review discusses the advantages and disadvantages of several WOLED architectures in terms of efficiency and color quality. Hindrances to their widespread acceptance as solid-state lighting sources are also noted.

White Organic Light‐Emitting Devices for Solid‐State Lighting

Poly(1,6-heptadiyne)-Based Materials by Metathesis Polymerization.

Four soluble perylene diimide derivatives (PDIs) have been prepared and their UV–visible and photoluminescence (PL) spectroscopy, cyclic voltammetry (CV) and thermal properties were studied. ITO/PEDOT∶PSS/poly(3-hexylthiophene) (P3HT)∶PDIs/LiF/Al photovoltaic devices were fabricated with PDIs as electron accepting and transporting materials. The highest incident photon-to-current conversion efficiency (IPCE) of 19% at 495 nm and the power conversion efficiency (PCE) of 0.18% under AM 1.5 (100 mW cm−2) with a short-circuit current density (JSC) of 1.32 mA cm−2, an open circuit voltage (VOC) of 0.36 V, and a fill factor (FF) of 0.38 have been achieved with 1 ∶ 4 ratio of P3HT
				∶
				N,N′-di(1-nonadecyl)perylene-3,4,9,10-bis(dicarboximide) (PDI-C9) after annealing at 80 °C for 1 h. 1,7-Bis(N-pyrrolidinyl)-N,N′-dicyclohexyl-3,4,9,10-perylenebis(dicarboximide) (5-PDI), which has the electron donating pyrrolidinyl group, absorbed the long wavelength region to give IPCE onset higher than 750 nm and the pyrrolidinyl group also raised the LUMO level of 5-PDI to render the high VOC (up to 0.71 V) in photovoltaic device.

Effects of functional groups at perylene diimide derivatives on organic photovoltaic device application

A new series of high brightness and luminance efficient poly(p-phenylenevinylene) (PPV)-based electroluminescent (EL) polymers, poly[2-{4-[5-(4-(3,7-dimethyloctyloxy)phenyl)-1,3,4-oxadiazole-2-yl]phenyloxy}-1,4-phenylenevinylene] (Oxa-PPV), poly[2-{2-((3,7-dimethyloctyl)oxy)phenoxy}-1,4-phenylenevinylene] (DMOP-PPV), and their corresponding random copolymers, poly{[2-{4-[5-(4-(3,7-dimethyloctyloxy)phenyl)-1,3,4-oxadiazole-2-yl]phenyloxy}-1,4-phenylenevinylene]-co-[2-{2-((3,7-dimethyloctyl)oxy) phenoxy}-1,4-phenylenevinylene]} (Oxa-PPV-co-DMOP-PPV), with an electron-deficient 1,3,4-oxadiazole unit on the side groups, were synthesized through the Gilch polymerization method. The newly designed and synthesized asymmetric molecular structures of Oxa-PPV, DMOP-PPV, and Oxa-PPV-co-DMOP-PPV were completely soluble in common organic solvents, and defect-free optical thin film was easily spin-coated onto the indium tin oxide (ITO) substrate. Oxa-PPV shows a high glass transition temperature (Tg), which might be an...

High-efficiency poly(p-phenylenevinylene)-based copolymers containing an oxadiazole pendant group for light-emitting diodes.

Highly efficient deep-blue fluorescent materials based on phenylquinoline–carbazole derivatives (PhQ-CVz, MeO-PhQ-CVz, and CN-PhQ-CVz) are synthesized for organic light-emitting diodes (OLEDs). The materials form high-quality amorphous thin films by thermal evaporation and the energy levels can be easily adjusted by the introduction of different electron-donating and electron-withdrawing groups on carbazoylphenylquinoline. Non-doped deep-blue OLEDs that use PhQ-CVz as the emitter show bright emission (Commission Internationale de L'Eclairage (CIE) coordinates, x = 0.156, y = 0.093) with an external quantum efficiency of 2.45%. Furthermore, the material works as an excellent host material for 4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl dopant to get high-performance OLEDs with excellent deep-blue CIE coordinates (x = 0.155, y = 0.157), high power efficiency (5.98 lm W−1), and high external quantum efficiency (5.22%).

Yeong-Soon Gal

Papers

Poly(1,6-heptadiyne)-Based Materials by Metathesis Polymerization.

Effects of functional groups at perylene diimide derivatives on organic photovoltaic device application

High-efficiency poly(p-phenylenevinylene)-based copolymers containing an oxadiazole pendant group for light-emitting diodes.

High‐Efficiency Deep‐Blue Light‐Emitting Diodes Based on Phenylquinoline/Carbazole‐Based Compounds

Poly(fluorenevinylene) Derivative by Gilch Polymerization for Light-Emitting Diode Applications