The First Single Polymer with Simultaneous Blue, Green, and Red Emission for White Electroluminescence

Abstract

The as-synthesized threads were washed by immersion in tetrahydrofuran for 1 day. The final inorganic fibers were then analyzed. TEM experiments were performed with a JEOL 2000-FX microscope (accelerating voltage of 200 kV). Scanning electron microscopy (SEM) observations were performed with a JEOL JSM-840A SEM operating at 10 kV. The specimens were carbon-coated prior to examination. XRD experiments were carried out on an X'pert MPD Philips instrument using Cu Ka radiation with an average current of 50 mA. The X-ray scattering measurements were performed with a NanoSTAR apparatus (Bruker). The X-ray source was a sealed-tube X-ray generator. The Cu Ka radiation was selected with two Göbbel mirrors and collimated with three pinholes. The scattered radiation was collected on a two-dimensional detector (HI-STAR). The diffuse scattering intensity I is plotted versus the scattering vector q = (4p/k)sinh (2) where 2h is the scattering angle and k is the incident wavelength. The sample-to-detector distance was 106 cm for the SAXS experiments. To detect reflections in the wide-angle region this distance was reduced to 7 cm. The solid-state 51 V MAS NMR spectrum of vanadium oxide fibers was obtained at 105.2 MHz on a Bruker Avance 400 spectrometer using a MAS 4 mm 1 H/broadband probe. Different fibers were cut and packed in 4 mm ZrO 2 rotors. Solid samples were spun at 12.5 kHz. The 51 V MAS NMR spectrum was acquired with a Hahn echo sequence (p/2-s-p-s acquisition) with a synchronized s and a 16-phase pulse program. The following acquisition parameters were used: spectral width of 1 MHz, pulse width of 1 ls, and a recycle time of 0.5 s. An accumulation of 115 200 transients was performed on the sample. Isotropic chemical shifts were referenced to pure VOCl 3 using a solution of 0.5 mol L -1 NaVO 3 (d iso = -578 ppm). A numerical simulation of the 51 V MAS spectrum was performed with the dmfit-QUA-SAR program [27]. This simulation included the effects of chemical shift anisotropy as well as first-and second-order quadrupolar interactions; both central and satellite transitions were considered. X-band ESR investigations were carried out with a Bruker ESP 300E spectrometer at ∼ 9.24 GHz and at both 298 and 77 K. The spectral width used was 2350-4350 G (1 G = 1 ×10 -4 T). Recently, white polymer light-emitting diodes (WPLEDs) have received particular attention because of their potential applications in backlight and full-color displays with color filters. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The combination of white emission and color filters should simplify the fabrication process of fine-pixel large- COMMUNICATIONS 2974

On the origin of high quality white light emission from a hybrid organic/inorganic light emitting diode using azide functionalized polyfluorene

“…[14][15][16][17][18][19] Due to the complexity of multi-chromophore polymers or blend systems there arises some difficulty in the formation of uniform multiple polymer films which can be attributed to the intrinsic phase separations among different components in the system. 2,3 It is also difficult to synthesize such multi-chromophore polymers in high yields.…”

“…2,5 For these reasons, light emitting conjugated polymers have been explored for their potential use, for instance, in full colour displays. [3][4][5][12][13][14][15][16][17][18][19] Recently, various strategies have been developed for the efficient use of those materials also as downconverting fluorescent materials on inorganic light emitting diodes or in electrically driven polymer based LEDs to generate white light.…”

How Smart LEDs Lighting Benefit Color Temperature and Luminosity Transformation

“…The color rendering index (CRI) standard, which is the gold standard for evaluating the performance of light sources, is inconsistent for use in evaluating LED light sources because of its emission characteristic [8,9]. Newly proposed color evaluation metrics such as color quality scale (CQS) [10], feeling of contrast index (FCI), color discrimination index (CDI), and color preference index (CPI) also failed to measure LED light sources fairly [11][12][13][14][15][16][17]. Moreover, these color evaluation standards are often measured under the same CCT, which are not appropriate for measuring LED light sources performance [18][19][20][21][22][23][24].…”

White emitting polyfluorene functionalized with azide hybridized on near-UV light emitting diode for high color rendering index

“…Similar approaches have also been successfully shown to make electrically driven polymer-based LEDs. Another method also shown in such polymer LEDs combines the emission of multiple primary colors, necessary for the full white light generation, on a single but rather complex polymer, with multiple chromophores each of which emits a primary color simultaneously [11][12][13][14][15][16]. However, in these approaches, it has been difficult to obtain very high color rendering index (CRI), which is required to be >80 for the future solid-state lighting [17].…”

“…First, polymers exhibit high absorption coefficients and feature high solid-state photoluminescence quantum efficiencies; second, they are easily processed, molecularly engineered, and coated using very low-cost techniques [2,8]. To this end, light emitting conjugated polymers have been extensively studied to explore their potential use, mainly in full color displays till date [6][7][8][9][10][11][12][13][14][15][16].…”