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

Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.

State of the Art and Prospects in Metal-Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.

Pyrene-based materials for organic electronics.

White organic light-emitting diodes (WOLEDs) offer a range of attractive characteristics and are in several regards conceptually different from most currently used light sources. From an application perspective, their advantages include a high power efficiency that rivals the performance of fluorescent lamps and inorganic LEDs and the potential for a very low cost of manufacturing. As flat-panel light sources they are intrinsically glare-free and generate light over a large area. WOLEDs are constantly improving in terms of performance, durability, and manufacturability, but these improvements require joint research efforts in chemistry and the materials sciences to design better materials as well as in physics and engineering to invent new device concepts and design suitable fabrication schemes, a process that has generated many exciting scientific questions and answers. This article reviews current developments in the field of WOLEDs and puts a special focus on new device concepts and on approaches to reliable and cost-efficient WOLED manufacturing.

White organic light-emitting diodes.

White organic light emitting diodes (WOLEDs) are promising devices for application in low energy consumption lighting since they combine the potentialities of high efficiency and inexpensive production with the appealing features of large surfaces emitting good quality white light. However, lifetime, performances and costs still have to be optimized to make WOLEDs commercially competitive as alternative lighting sources. Development of efficient and stable emitters plays a key role in the progress of WOLED technology. This tutorial review discusses the main approaches to obtain white electroluminescence with organic and organometallic emitters. Representative examples of each method are reported highlighting the most significant achievements together with open issues and challenges to be faced by future research.

Electroluminescent materials for white organic light emitting diodes

Semisacrificial Template Growth of Self-Supporting MOF Nanocomposite Electrode for Efficient Electrocatalytic Water Oxidation

The first single polymer with simultaneous blue, green, and red emission for white electroluminescence

Electrochemical reduction of CO2 to valuable fuels is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide potential window is challenging. Herein, atomically thin bismuthene (Bi-ene) is pioneeringly obtained by an in situ electrochemical transformation from ultrathin bismuth-based metal-organic layers. The few-layer Bi-ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100 %), large partial current density, and quite good stability in a potential window exceeding 0.35 V toward formate production. It even deliver current densities that exceed 300.0 mA cm-2 without compromising selectivity in a flow-cell reactor. Using in situ ATR-IR spectra and DFT analysis, a reaction mechanism involving HCO3- for formate generation was unveiled, which brings new fundamental understanding of CO2 reduction.

Metal-Organic Layers Leading to Atomically Thin Bismuthene for Efficient Carbon Dioxide Electroreduction to Liquid Fuel.

New single-polymer electroluminescent systems containing two individual emission species—polyfluorenes as a blue host and 2,1,3-benzothiadiazole derivative units as an orange dopant on the main chain—have been designed and synthesized. The resulting single polymers are found to have highly efficient white electroluminescence with simultaneous blue (λmax = 421 nm/445 nm) and orange emission (λmax = 564 nm) from the corresponding emitting species. The influence of the photoluminescence (PL) efficiencies of both the blue and orange species on the electroluminescence (EL) efficiencies of white polymer light-emitting diodes (PLEDs) based on the single-polymer systems has been investigated. The introduction of the highly efficient 4,7-bis(4-(N-phenyl-N-(4-methylphenyl)amino)phenyl)-2,1,3-benzothiadiazole unit to the main chain of polyfluorene provides significant improvement in EL efficiency. For a single-layer device fabricated in air (indium tin oxide/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid/polymer/Ca/Al), pure-white electroluminescence with Commission Internationale de l'Eclairage (CIE) coordinates of (0.35,0.32), maximum brightness of 12 300 cd m–2, luminance efficiency of 7.30 cd A–1, and power efficiency of 3.34 lm W–1 can be obtained. This device is approximately two times more efficient than that utilizing a single polyfluorene containing 1,8-naphthalimide moieties, and shows remarkable improvement over the corresponding blend systems in terms of efficiency and color stability. Thermal treatment of the single-layer device before cathode deposition leads to the further improvement of the device performance, with CIE coordinates of (0.35,0.34), turn-on voltage of 3.5 V, luminance efficiency of 8.99 cd A–1, power efficiency of 5.75 lm W–1, external quantum efficiency of 3.8 %, and maximum brightness of 12 680 cd m–2. This performance is roughly comparable to that of white organic light-emitting diodes (WOLEDs) with multilayer device structures and complicated fabrication processes.

White Electroluminescence from a Single‐Polymer System with Simultaneous Two‐Color Emission: Polyfluorene as the Blue Host and a 2,1,3‐Benzothiadiazole Derivative as the Orange Dopant

Metal–organic frameworks (MOFs) can be utilized as superior precursors to pyrolytically achieve the single-atom catalysts. However, most of the atomic active sites are buried inside the microporous carbon matrix, which severely impedes the accessibility of active sites and limits mass transport. Herein, the mesoporous carbon nanoframes with hierarchical pore size distribution and atomically dispersed Fe–Nx active sites were synthesized from Fe-doped MOF precursors. The dense Fe atoms within the nanostructures are dispersed in single-atom level with metalloporphyrin-like Fe–N4 configuration. The introduction of plentiful large mesopores into the nanoframes would not only enhance the accessibility of abundant single-atom active sites, but also boost mass and charge transports. Such distinctive nanostructure led to exceptional bifunctional electrocatalytic performances for oxygen reduction reaction, with more positive onset potential (1.01 V vs. 0.97 V) and half-wave potential (0.89 V vs. 0.82 V) compared with the commercial Pt/C, and electrochemical carbon dioxide reduction.

Metal–organic framework-derived mesoporous carbon nanoframes embedded with atomically dispersed Fe–Nx active sites for efficient bifunctional oxygen and carbon dioxide electroreduction

Dong-Dong Ma

Papers

Semisacrificial Template Growth of Self-Supporting MOF Nanocomposite Electrode for Efficient Electrocatalytic Water Oxidation

The first single polymer with simultaneous blue, green, and red emission for white electroluminescence

Metal-Organic Layers Leading to Atomically Thin Bismuthene for Efficient Carbon Dioxide Electroreduction to Liquid Fuel.

White Electroluminescence from a Single‐Polymer System with Simultaneous Two‐Color Emission: Polyfluorene as the Blue Host and a 2,1,3‐Benzothiadiazole Derivative as the Orange Dopant

Metal–organic framework-derived mesoporous carbon nanoframes embedded with atomically dispersed Fe–Nx active sites for efficient bifunctional oxygen and carbon dioxide electroreduction