Improved Power Conversion Efficiency and Stability of Perovskite Solar Cells Induced by Molecular Interaction with Poly(ionic liquid) Additives.

Ionic liquid (IL) additives proved to have a positive effect on the device efficiency and stability of perovskite solar cells. However, since ILs are small molecules and undergo Coulomb interactions, they can easily aggregate and evaporate over long times, which would cause instabilities during a long-term device operation. To overcome these problems, we polymerize ILs into macromolecules and incorporate them into perovskite films as well as into the corresponding solar cells.

Ultraviolet lasing action in ZnO nanosheets.

We report room-temperature ultraviolet lasing action in large quantities of uniform multilayer ZnO nanosheets grown by a vapor-transport method via thermal evaporation of Zn powder. An excellent multimode lasing emission at a center wavelength of 390 nm with a mode linewidth less than 0.33 nm occurs above an excitation threshold of 8 mJ pulse(-1) cm(-2).

Realization of blue, green, and white inverted microcavity top-emitting organic light-emitting devices based on the same emitting layer.

High efficiency blue, green, and white inverted microcavity top-emitting organic light-emitting devices based on blue emitter p-bis(p-N,N-diphenyl-amino-styryl) benzene-doped 2-methyl-9,10-di(2-naphthyl) anthracene as the emitting layer are demonstrated. The different colors can be well realized by simply changing the thickness of the hole-transporting layer, thus modifying the cavity length to obtain various resonance wavelengths. The comprehensive analysis on the emission mechanism is presented.

Amplified spontaneous emission from an Ag-backed red-fluorescent-dye-doped polymer film.

We demonstrate that the amplified spontaneous emission (ASE) in an Ag-backed red-fluorescent-dye-doped polymer film can be controlled by the effect of the film thickness. Optical losses associated with the metallic contacts necessary for charge injection, an obstacle to the development of an electrically pumped organic solid-state laser, may be possible to be reduced by increasing the gain medium layer thickness. The study of ASE characteristics of Ag-backed 4-(Dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB)-doped polystyrene (PS) films with different thicknesses shows that increasing the film thickness can reduce the influence of the Ag layer.

Highly efficient inverted top-emitting organic light-emitting diodes using a lead monoxide electron injection layer.

By introducing an effective electron injection layer (EIL) material, i.e., lead monoxide (PbO), combined with the optical design in device structure, a high efficiency inverted top-emitting organic light-emitting diode (ITOLED) with saturated and quite stable colors for different viewing angles is demonstrated.