We demonstrate a series of ultrastable, highly luminescent CH3NH3PbBr3 (MAPbBr3) green emitting organic-inorganic perovskites (OIP) - polymer composite films achieved by a simple yet general strategy, to be used together with red emitters as down-converters for blue LEDs in display technology. These composite films exhibit high photoluminescence quantum yield (PLQY) of up to 48%, high color purity with FWHM (full width at half maximum) as narrow as 18 nm. When combined with blue LED and CdSe-based quantum dots-polymer films or red phosphors as LCD backlight, we can achieve a relatively wide color gamut in Rec. 2020 color space.
Two bisindolylmaleimide derivatives were prepared in good yields, characterized and successfully employed in the fabrication of organic light-emitting-diodes (OLEDs). The absorption spectra and photoluminescence spectra of the compounds in solution and in thin film were also measured and they show larger Stokes shifts (>100nm). With the electroluminescence devices configured as ITO/NPB/dopant:Alq3 /Alq3/LiF/Al, they exhibit yellow (A) and orange (B) color. In particularly, the two devices can be turned on at 5.2 V (device A) and 5.9V (device B), and reached the maximum brightness of 15066 and 8593cd/m2 at 21V, respectively. From the cyclic voltammetry and the onset absorption, the highest occupied molecule orbital (HOMO) and the lowest unoccupied molecule orbital (LUMO) energy levels can be estimated as A (5.3, 2.9eV) and B (5.4, 3.1eV).