Characterizing the Conformational Distribution in an Amorphous Film of an Organic Emitter and Its Application in a "Self-Doping" Organic Light-Emitting Diode.

The conformational distribution and mutual interconversion of thermally activated delayed fluorescence (TADF) emitters significantly affect the exciton utilization. However, their influence on the photophysics in amorphous film states is still not known due to the lack of a suitable quantitative analysis method. Herein, we used temperature-dependent time-resolved photoluminescence spectroscopy to quantitatively measure the relative populations of the conformations of a TADF emitter for the first time.

Single-Crystalline Silicon Frameworks: A New Platform for Transparent Flexible Optoelectronics.

Single-crystalline silicon (sc-Si) is the dominant semiconductor material for the modern electronics industry. Despite their excellent photoelectric and electronic properties, the rigidity, brittleness, and nontransparency of commonly used silicon wafers limit their application in transparent flexible optoelectronics. In this study, a new type of Si microstructure, named single-crystalline Si frameworks (sc-SiFs), is developed, through a combination of wet-etching and microfabrication technologies.

Centimeter-Long Single-Crystalline Si Nanowires.

The elongation of free-standing one-dimensional (1D) functional nanostructures into lengths above the millimeter range has brought new practical applications as they combine the remarkable properties of nanostructured materials with macroscopic lengths. However, it remains a big challenge to prepare 1D silicon nanostructures, one of the most important 1D nanostructures, with lengths above the millimeter range. Here we report the unprecedented preparation of ultralong single-crystalline Si nanowires with length up to 2 cm, which can function as the smallest active material to facilitate the miniaturization of macroscopic devices.

Self-assembly and hierarchical patterning of aligned organic nanowire arrays by solvent evaporation on substrates with patterned wettability.

The controlled growth and alignment of one-dimensional organic nanostructures at well-defined locations considerably hinders the integration of nanostructures for electronic and optoelectronic applications. Here, we demonstrate a simple process to achieve the growth, alignment, and hierarchical patterning of organic nanowires on substrates with controlled patterns of surface wettability. The first-level pattern is confined by the substrate patterns of wettability.

Monolayer graphene film on ZnO nanorod array for high-performance Schottky junction ultraviolet photodetectors.

A new Schottky junction ultraviolet photodetector (UVPD) is fabricated by coating a free-standing ZnO nanorod (ZnONR) array with a layer of transparent monolayer graphene (MLG) film. The single-crystalline [0001]-oriented ZnONR array has a length of about 8-11 μm, and a diameter of 100∼600 nm. Finite element method (FEM) simulation results show that this novel nanostructure array/MLG heterojunction can trap UV photons effectively within the ZnONRs.

Fabrication of p-type ZnSe:Sb nanowires for high-performance ultraviolet light photodetector application.

p-type ZnSe nanowires (NWs) with tunable electrical conductivity were fabricated on a large scale by evaporating a mixed powder composed of ZnSe and Sb in different ratios. According to the structural characterization, the Sb-doped ZnSe NWs are of single crystalline form and grow along the [001] direction. The presence of Sb in the ZnSe NWs was confirmed by XPS spectra.

Sn-catalyzed synthesis of SnO2 nanowires and their optoelectronic characteristics.

We report the rational synthesis of one-dimensional SnO(2) nanowires (SnO(2)NWs) via a Sn-catalyzed vapor-liquid-solid (VLS) growth mechanism, in which Sn nanoparticles can direct the oriented growth of SnO(2)NWs at high temperature. I-V measurement of a field effect transistor made of individual SnO(2)NWs exhibits typical n-type semiconducting characteristics with an electron mobility and concentration of 14.36 cm(2) V( - 1) s( - 1) and 1.