A bilayer cathode consisting of aminoalkyl‐substituted polyfluorene and Al layers (see Figure) effectively injects electrons into an electroluminescent polymer emitting layer. The alcohol‐ and water‐soluble polyfluorene, and its quaternized salt, can be used to fabricate polymer light‐emitting diodes with device performance comparable to, or exceeding, devices using Ba/Al cathodes.

We report on the realization of wide band gap (5–6 eV), single-phase, metastable, and epitaxial MgxZn1−xO thin-film alloys grown on sapphire by pulsed laser deposition. We found that the composition, structure, and band gaps of the MgxZn1−xO thin-film alloys depend critically on the growth temperature. The structural transition from hexagonal to cubic phase has been observed for (Mg content greater than 50 at. %) (1⩾x⩾0.5) which can be achieved by growing the film alloys in the temperature range of 750 °C to room temperature. Interestingly, the increase of Mg content in the film has been found to be beneficial for the epitaxial growth at relatively low growth temperature in spite of a large lattice mismatch between sapphire and cubic MgZnO alloys.

Multifunctional electronic textiles (E-textiles) with embedded electric circuits hold great application prospects for future wearable electronics. However, most E-textiles still have critical challenges, including air permeability, satisfactory washability, and mass fabrication. In this work, we fabricate a washable E-textile that addresses all of the concerns and shows its application as a self-powered triboelectric gesture textile for intelligent human-machine interfacing. Utilizing conductive carbon nanotubes (CNTs) and screen-printing technology, this kind of E-textile embraces high conductivity (0.2 kΩ/sq), high air permeability (88.2 mm/s), and can be manufactured on common fabric at large scales. Due to the advantage of the interaction between the CNTs and the fabrics, the electrode shows excellent stability under harsh mechanical deformation and even after being washed. Moreover, based on a single-electrode mode triboelectric nanogenerator and electrode pattern design, our E-textile exhibits highly sensitive touch/gesture sensing performance and has potential applications for human-machine interfacing.

Within organic optoelectronics, polymer light-emitting devices (PLEDs) are regarded as an important class of devices which can convert electricity into light as a result of radiative decay taking place in semiconducting polymers. Recently, much effort has been devoted to developing efficient white emitting PLEDs for their potential applications in next-generation flat-panel displays and solid-state lighting sources. In this tutorial review, we will summarize the advances in white emitting polymers and devices published up till April 2009 by major prestigious institutions in this field. Special attention is paid to the recent progress in highly efficient devices realized by doping an electrophosphorescent guest into a polymer host and other approaches. Also we will summarize the new strategies to realize white emission with simultaneous fluorescent and/or phosphorescent emission from a single polymer in which singlet and/or triplet chromophores are incorporated into the polymer side or main chain through a covalent bond.

A novel series of semiconducting conjugated copolymers, derived from alkyl-substituted fluorene, 4,7-diselenophen-2‘-yl-2,1,3-benzothiadiazole (SeBT), and 4,7-diselenophen-2‘-yl-2,1,3-benzoselenadiazole (SeBSe), was synthesized by a palladium-catalyzed Suzuki coupling reaction with various feed ratios. The optical band gap of copolymers is very low, 1.87 eV for SeBT and 1.77 eV for SeBSe. The efficient fast energy transfer from fluorene segments to narrow-band-gap sites was observed. The emission of photoluminescence and electroluminescence is dominated by narrow-band-gap species and peaked at 670−790 nm, in the range from deep-red to near-infrared (NIR). The external electroluminescent (EL) quantum efficiencies reached 1.1% and 0.3% for devices from these two types of copolymers, respectively. Bulk−heterojunction polymer photovoltaic cells (PPVCs) made from composite thin film of the copolymer 9,9-dioctylfluorene and SeBT (PFO−SeBT) in blend with fullerene derivative [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as an active layer show promising performances. The energy conversion efficiency (ECE) is up to 1% under AM1.5 solar simulator (78.2 mW/cm2). The spectral response is extended up to 675 and 750 nm for PPVCs from PFO−SeBT and PFO−SeBSe, respectively.