Electric field poled organic electro-optic materials: state of the art and future prospects.

Long-range surface plasmon polaritons (LRSPPs) are optical surface waves that
 propagate along a thin symmetric metal slab or stripe over an appreciable length
 (centimeters). Vigorous interest in LRSPPs has stimulated a large number of studies
 over three decades spanning a broad topical landscape. Naturally, a good segment of
 the literature covers fundamentals such as modal characteristics, excitation, and
 field enhancement. But a large portion also involves the LRSPP in diverse phenomena,
 including nonlinear interactions, molecular scattering, fluorescence,
 surface-enhanced Raman spectroscopy, transmission through opaque metal films and
 emission extraction, amplification and lasing, surface characterization, metal
 roughness and islandization, optical interconnects and integrated structures,
 gratings, thermo-, electro- and magneto-optics, and (bio)chemical sensing. Despite
 the breadth and depth of the research conducted to date, much remains to be
 uncovered, and the scope for future investigations is broad. We review the properties
 of the LRSPP, survey the literature involving this wave, and discuss the prospects
 for applications. Avenues for further work are suggested.

Long-range surface plasmon polaritons

In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers.

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Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach

Low bandgap and two-dimensional (2D)-conjugated copolymers based on benzo[1,2-b:4,5-b′]dithiophene with conjugated thiophene side chains (BDTT) and thieno[3,4-b]thiophene with electron-withdrawing substituents (TT) are attractive high efficiency polymer donor materials in polymer solar cells (PSCs). In this work, we introduced an alkylthio substituent on the thiophene side chain in the polymer and synthesized a new low bandgap 2D-conjugated polymer PBDTT-S-TT. The alkylthio substituent increased the hole mobility of the polymer to 4.08 × 10−3 cm2 V−1 s−1 and down-shifted the HOMO energy level of the polymer by 0.11 eV with absorption of the polymer film red-shifted slightly. The PSCs based on PBDTT-S-TT as a donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) as an acceptor without solvent additive treatment demonstrated a high open-circuit voltage (Voc) of 0.84 V, leading to a high power conversion efficiency (PCE) of 8.42%, under the illumination of AM 1.5 G 100 mW cm−2. For comparison, the Voc and PCE of the devices based on the corresponding parent polymer PBDTT-TT with the device optimization of 3% DIO additive treatment are 0.77 V and 7.38%, respectively. The enhanced Voc value of 0.84 V for the PSC based on PBDTT-S-TT should be benefited from the down-shifted HOMO energy level of the polymer. The results indicate that the alkylthio substitution is an effective way to further improve the photovoltaic performance of the 2D-conjugated polymer donor materials in PSCs.

Improvement of open-circuit voltage and photovoltaic properties of 2D-conjugated polymers by alkylthio substitution

Blue organic light-emitting diodes (OLEDs) can play a critical role in the field of organic electroluminescence (EL). As the most important applications of OLEDs, both new generation full-color flat-panel displays and future energy-saving solid-state lighting sources require blue color EL to fulfill their functions properly. However, considerable challenges still exist in searching for highly efficient, color stable, and long-lifespan materials and devices that emit blue color, especially in the development of deep-blue emitters, which are indispensable for high-quality displays and lighting sources. Encouragingly, great progress has been made in the area of deep-blue OLEDs in recent years with continuous efforts made by scientists, who are responsible for the significant achievements in the field of OLEDs. Hence, in this review, the crucial tactics employed to obtain high performance deep-blue emitters are presented, including polymers, dendrimers, small organic molecules, delayed fluorescent systems, and phosphorescent emitters. Moreover, the future perspectives and ongoing challenges of this research frontier are also highlighted.

Recent advances of the emitters for high performance deep-blue organic light-emitting diodes

Diels-Alder crosslinkable dendritic nonlinear optical chromophore compounds, films and crosslinked polymer composites formed from the chromophore compounds, methods for making and using the chromophore compounds, films, and crosslinked polymer composites, and electro-optic devices that include films and crosslinked polymer composites formed from the chromophore compounds.

Xing-Hua Zhou

Papers

Diels-alder crosslinkable dendritic nonlinear optic chromophores and polymer composites