Spectral conversion of InGaN ultraviolet microarray light-emitting diodes using fluorene-based red-, green-, blue-, and white-light-emitting polymer overlayer films

Abstract

We report the fabrication of hybrid organic/inorganic semiconductor light-emitting devices that operate across the entire visible spectrum. The devices are based on a series of blue-, green-, and red-light-emitting polyfluorene materials that convert the emission from an array of micron-sized ultraviolet InGaN light-emitting diodes. We also demonstrate white-light-emitting versions of these hybrid devices by employing single films of carefully adjusted polyfluorene blends in which cascade energy transfer occurs between the constituent materials. The spectral and operating characteristics of the devices are described in detail. Such organic emission layer/inorganic light-emitting diode (LED) array based devices may provide a promising route to the fabrication of low-cost full-color microdisplays and other instrumentation devices.

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

“…Among them, the strategies involving wavelength converting WLEDs and white emitting polymer diodes are more commonly used. [1][2][3][4][5] Different photoemitters such as phosphors, 6,7 nanocrystals, [8][9][10][11] polymers, 2 and hybrid nanocrystals/polymer systems 12 have been used on electrically driven LEDs for the generation of white light by the wavelength conversion technique. Because of their versatility and superior optical properties, conjugated polymers are on their way to earning an irreplaceable position for use in white light generation though phosphors have thus far been most extensively used for white light applications.…”

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

“…The construction of such white emitting polymer thin films is essentially based on either preparing layer-by-layer assembly of multiple polymers or blending polymers [2,6]. Similar approaches have also been successfully shown to make electrically driven polymer-based LEDs.…”

“…Recently, a wide range of conducting polymers have been investigated as luminescent down-converting materials to generate white light on inorganic light emitting diodes [2]. The construction of such white emitting polymer thin films is essentially based on either preparing layer-by-layer assembly of multiple polymers or blending polymers [2,6].…”

“…Today in solid-state lighting, wavelength-converting WLEDs are more commonly used than multi-chip WLEDs and monolithic WLEDs [1,2]. In the wavelength conversion technique, different photoemitters such as phosphors [1], nanocrystals [3][4][5], polymers [2,[6][7][8], and nanocrystal-polymer combination [9] have been successfully used by integrating them on pump LED sources. Among them, although phosphor is currently the most widely used wavelength-converting material, polymers also offer a number of benefits that may make them attractive for use in white light generation.…”

“…Among them, although phosphor is currently the most widely used wavelength-converting material, polymers also offer a number of benefits that may make them attractive for use in white light generation. 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].…”