Photosynthesis is used by plants, algae and bacteria to convert solar energy into stable chemical energy. The initial stages of this process--where light is absorbed and energy and electrons are transferred--are mediated by reaction centres composed of chlorophyll and carotenoid complexes. It has been previously shown that single small molecules can be used as functional components in electric and optoelectronic circuits, but it has proved difficult to control and probe individual molecules for photovoltaic and photoelectrochemical applications. Here, we show that the photocurrent generated by a single photosynthetic protein-photosystem I-can be measured using a scanning near-field optical microscope set-up. One side of the protein is anchored to a gold surface that acts as an electrode, and the other is contacted by a gold-covered glass tip. The tip functions as both counter electrode and light source. A photocurrent of ∼10 pA is recorded from the covalently bound single-protein junctions, which is in agreement with the internal electron transfer times of photosystem I.

Precisely controlling well-defined, stable single-molecule junctions represents a pillar of single-molecule electronics. Early attempts to establish computing with molecular switching arrays were partly challenged by limitations in the direct chemical characterization of metal-molecule-metal junctions. While cryogenic scanning probe studies have advanced the mechanistic understanding of current- and voltage-induced conformational switching, metal-molecule-metal conformations are still largely inferred from indirect evidence. Hence, the development of robust, chemically sensitive techniques is instrumental for advancement in the field. Here we probe the conformation of a two-state molecular switch with vibrational spectroscopy, while simultaneously operating it by means of the applied voltage. Our study emphasizes measurements of single-molecule Raman spectra in a room-temperature stable single-molecule switch presenting a signal modulation of nearly 2 orders of magnitude.

We have designed and synthesized a series of 9-anthrylpyrazole derivatives 1,4-bis(3-(9-anthryl)-1-pyrazolylmethyl)benzene (1), 1-(3-(9-anthryl)-1-pyrazolylmethyl)-4-(5-(9-anthryl)-1-pyrazolylmethyl)benzene (2), 1,4-bis(3-(9-anthryl)-1-pyrazolyl)benzene (3), and 1-(3-(9-anthryl)-1-pyrazolyl)-4-(5-(9-anthryl)-1-pyrazolyl)benzene (4). All compounds formed two types of crystals that exhibited anthracene-arrangement-dependent emission colors. For instance, crystal 1a with strong π-overlap between anthracene moieties exhibited an emission maximum at 515 nm, while 1b with no such interchromophore interactions displayed an emission band at 424 nm. The fluorescence quantum yield (ΦF) measurements showed that the blue-emitting crystals have high quantum yields (ΦF = 0.46 for 1b, 0.90 for 2a, 0.91 for 2b, 0.77 for 3b, and 0.51 for 4a), suggesting their potential as blue emitters in optoelectronics.

A high-efficiency and pure white OLED has been realized by only doping one novel phosphorescent orange-light-emitting complex (bzq) 2 Ir(dipba) into a suitable deep-blue-emitting fluorescent complex Bepp 2 as an emissive layer. The highest efficiency for white OLEDs with a simple HTL-EML-ETL architecture, with a peak power efficiency (PE) of 48.8 lm W À1 and a peak external quantum efficiency (EQE) of 27.8%, has been realized by employing both singlet and triplet excitons for emission. The PE and EQE at the applicable brightness of 1000 cd m À2 are 37.5 lm W À1 and 36.8%, respectively.

Four diboron-bridged ladder molecules 1-4 have been designed and synthesized. X-ray diffraction analysis revealed that the bulky phenyl substituents on boron centers efficiently prevented π stacking of the luminescent ladder unit. Characterizations of these complexes demonstrated that the construction of diboron-containing ladder-type skeletons endowed these materials with good thermal stability, high fluorescence quantum yields, and strong electron affinity. The highly efficient nondoped organic light-emitting diodes using complexes 1 and 2 as electron-transporting emitters exhibited maximum luminance values of 16,930 and 18,060 cd/m(2) with turn-on voltages of 3.5 and 2.5 V as well as maximum luminous efficiencies of 6.4 and 5.4 cd/A, respectively.

Four diboron-contained ladder-type pi-conjugated compounds 1-4 were designed and synthesized. Their thermal, photophysical, electrochemical properties, as well as density functional theory calculations, were fully investigated. The single crystals of compounds 1 and 3 were grown, and their crystal structures were determined by X-ray diffraction analysis. Both compounds have a ladder-type pi-conjugated framework. Compounds 1 and 2 possess high thermal stabilities, moderate solid-state fluorescence quantum yields, as well as stable redox properties, indicating that they are possible candidates for emitters and charge-transporting materials in electroluminescent (EL) devices. The double-layer device with the configuration of [ITO/NPB (40 nm)/1 or 2 (70 nm)/LiF (0.5 nm)/Al (200 nm)] exhibited good EL performance with the maximum brightness exceeding 8000 cd/m(2).

An array of 50μm×50μm polymer waveguides with 45° total internal reflection (TIR) wideband coupling mirrors were fabricated by soft molding to achieve fully embedded boardlevel optoelectronic interconnects. The 45° TIR coupling mirrors were formed at the ends of the waveguides to provide surface normal light coupling between waveguides and optoelectronic devices. Three-dimensional optoelectronic interconnects were replicated in one-step transfer by the soft molding technique. The measured propagation loss of the multimode waveguide was 0.16dB∕cm at 850nm wavelength. The coupling efficiency of the silver-coated 45° micromirrors buried under the top cladding was 92% with low polarization sensitivity.

With the high energy ball milling method, a Co9S8-decorated reduced graphene oxide (RGO) composite, which shows excellent hydrogen storage capacity, has been successfully fabricated with a well-organized layered structure. Moreover, the stabilized mechanism of the well-organized layered structure is investigated and attributed to the strong interactions between Co9S8 and defective RGO. The C-S bond interaction is identified and the hydrogen storage process is also studied with different analysis methods. Finally, an optimized Co9S8 to RGO weight ratio of 6:1 shows excellent electrochemical performances in terms of the excellent cycling stability and competitive hydrogen storage capacity of 4.86 wt%.