The International Telecommunication Union announced a new color gamut standard of broadcast service television (BT 2020) for ultra-high-definition TV in 2012. To satisfy the wide-color gamut standard of BT 2020, monochromatic red (R), green (G), and blue (B) emissions require a small full width at half-maximum, which is an important property for improving color purity. Although organic light-emitting diode (OLED) displays are currently one of the main types of display technologies, their broad emission via strong vibronic coupling between ground and excited states is a major hurdle to overcome in the development of next-generation wide-color gamut displays. Thus, the development of OLED emitters with narrowband R–G–B emissions is of great significance. In this review, the recent progress in the development of OLED materials with narrowband emission is summarized by grouping them into fluorescent, phosphorescent, and thermally activated delayed fluorescent emitters to reveal the correlation between molecular structures, optical properties, and device characteristics. We discuss rational molecular design strategies to achieve narrow photoluminescence and electroluminescence and the underlying mechanisms for controlling the emission bandwidth. Finally, the challenges in the realization of wide-color gamut OLED displays and the future prospects of such devices are discussed.

Abstract. Many natural anti-DNA antibodies (Abs) have the ability to translocate across the plasma membrane and localize in the nucleus of mammalian cells, frequently leading to cytotoxicity to cells. Herein, we report detailed intracellular trafficking routes and cytotoxicity in HeLa cells for a single chain variable fragment (scFv) Ab, 3D8, which is an anti-DNA Ab capable of hydrolyzing both DNA and RNA. The intracellular penetration of 3D8 scFv occurred by caveolae/lipid raft endocytosis. The time-course chasing experiments revealed that 3D8 scFv escaped directly from the caveosome into the cytosol and remained in the cytosol without further trafficking into endosomes, lysosomes, endoplasmic reticulum, Golgi, or nucleus. The cytosolically localized 3D8 scFv maintained its nuclease activity to hydrolyze cellular RNAs, mainly mRNAs, eventually triggering apoptotic cell death. Our results demonstrate that 3D8 scFv has a unique intracellular trafficking route of localizing in the cytosol, thereby exhibiting cytotoxicity due to its nuclease activity.

The energy level alignments at donor/acceptor interfaces in organic photovoltaics (OPVs) play a decisive role in device performance. However, little is known about the interfacial energetics in polymer OPVs due to technical issues of the solution process. Here, the frontier ortbial line-ups at the donor/acceptor interface in high performance polymer OPVs, PTB7/PC71BM, were investigated using in situ UPS, XPS and IPES. The evolution of energy levels during PTB7/PC71BM interface formation was investigated using vacuum electrospray deposition, and was compared with that of P3HT/PC61BM. At the PTB7/PC71BM interface, the interface dipole and the band bending were absent due to their identical charge neutrality levels. In contrast, a large interfacial dipole was observed at the P3HT/PC61BM interface. The measured photovoltaic energy gap (EPVG) was 1.10 eV for PTB7/PC71BM and 0.90 eV for P3HT/PC61BM. This difference in the EPVG leads to a larger open-circuit voltage of PTB7/PC71BM than that of P3HT/PC61BM.

The development of stable and efficient oxygen evolutional electrocatalysts is fundamental to the production of hydrogen by water electrolysis. However, so far the majority of electrocatalysts require a substantial overpotential (η) (approximately >250 mV) to catalyze the bottleneck oxygen evolution reaction (OER). To overcome this large overpotential for OER, herein we report the growth of nickel–cobalt–selenide (NiCoSe2) nanosheets over 3D nickel foam (NF) via a facile and scalable electrodeposition method. The resulting 3D NiCoSe2/NF hybrid electrode requires an overpotential of merely 183 mV to reach the current density (J) of 10 mA cm–2. To the best of our knowledge, this is the lowest η value reported so far for any earth-abundant material-based OER electrocatalyst to attain the same current density. Moreover, a significant reduction in Tafel slope (88 mV dec–1) is observed between bare NF and NiCoSe2/NF. Hence, as a result, the 3D hybrid NiCoSe2/NF OER electrode outperforms the previously reported electrocatalysts including the expensive state-of-the-art OER electrocatalysts like RuO2 and IrO2. Such enhancement in the OER catalytic efficiency of NiCoSe2 nanosheets over NF can be attributed to its enormous electrochemical active surface area (ECSA) (108 cm2), large roughness factor (270), highly conductive NF substrate, and the presence of multiple catalytically active OER species (NiOOH and CoOOH) on its surface. In addition, 3D hybrid NiCoSe2/NF electrocatalyst was tested for hydrazine oxidation for its bifunctional utilization. Much lower onset potential values (−0.7 V vs SCE) and high current densities (>200 mA cm–2) are observed for 3D hybrid NiCoSe2/NF when benchmarked against bare NF (−0.4 V and <50 mA cm–2). Furthermore, 3D hybrid NiCoSe2/NF OER electrode shows excellent stability of 50 h for continuous OER in strongly alkaline solutions while maintaining its enormous ECSA, chemical composition, and structural morphology. The excellent bifunctional electrocatalytic activity, long-term stability, and facile preparation method enable NiCoSe2/NF hybrid electrode to be a viable candidate for its widespread use in various water-splitting technologies.

Copper thiocyanate (CuSCN) is known as a promising hole transport layer in organic photovoltaics (OPVs) due to its good hole conduction and exciton blocking abilities with high transparency. Despite its successful device applications, the origin of its hole extraction enhancement in OPVs has not yet been understood. Here, we investigated the electronic structure of CuSCN and the energy level alignment at the poly(3-hexylthiophene-2,5-diyl) (P3HT)/CuSCN/ITO interfaces using ultraviolet photoelectron spectroscopy. The band-tail states of CuSCN close to the Fermi level (EF) were observed at 0.25 eV below the EF, leading to good hole transport. The CuSCN interlayer significantly reduces the hole transport barrier between ITO and P3HT due to its high work function and band-tail states. The barrier reduction leads to enhanced current density-voltage characteristics of hole-dominated devices. These results provide the origin of hole-extraction enhancement by CuSCN and insights for further application.

Carbohydrate microarrays were used for the simultaneous screening of various glycans whose binding to the cell-surface lectin elicits cellular response.

Efficient exciton management is a key issue to improve the power conversion efficiency of organic photovoltaics (OPVs). It is well known that the insertion of an exciton blocking layer (ExBL) having a large band gap promotes the efficient dissociation of photogenerated excitons at the donor-acceptor interface. However, the large band gap induces an energy barrier which disrupts the charge transport. Therefore, building an adequate strategy based on the knowledge of the true charge transport mechanism is necessary. In this study, the true electron transport mechanism of a bathocuproine (BCP) ExBL in OPVs is comprehensively investigated by in situ ultraviolet photoemission spectroscopy, inverse photoemission spectroscopy, density functional theory calculation, and impedance spectroscopy. The chemical interaction between deposited Al and BCP induces new states within the band gap of BCP, so that electrons can transport through these new energy levels. Localized trap states are also formed upon the Al-BCP interaction. The activation energy of these traps is estimated with temperature-dependent conductance measurements to be 0.20 eV. The Al-BCP interaction induces both transport and trap levels in the energy gap of BCP and their interplay results in the electron transport observed.

In organolead halide perovskite solar cells (PSCs), interfacial properties between the perovskite and charge transport layers are the critical factors governing charge extraction efficiency. In this study, the effect of interfacial energetics between two-step spin-coated methylammonium lead iodide (MAPbI) with different methylammonium iodide (MAI) concentrations and C on the charge extraction efficiency is investigated. The electronic structures of perovskite films are significantly varied by the MAI concentrations due to the changes in the residual precursor and MA defect content. As compared to the optimum PSCs with 25 mg mL MAI, PSCs with other MAI concentrations show significantly lower power conversion efficiencies and severe hysteresis. The energy level alignment at the C/MAPbI interface determined by ultraviolet and inverse photoelectron spectroscopy measurements reveals the origin of distinct differences in device performances. The conduction band offset at the C/MAPbI interface plays a crucial role in efficient charge extraction in PSCs.