White light generation using CdSe/ZnS core–shell nanocrystals hybridized with InGaN/GaN light emitting diodes

Abstract

We introduce white light generation using CdSe/ZnS core–shell nanocrystals of single, dual, triple and quadruple combinations hybridized with InGaN/GaN LEDs. Such hybridization of different nanocrystal combinations provides the ability to conveniently adjust white light parameters including the tristimulus coordinates (x,y), correlated colour temperature (Tc) and colour rending index (Ra). We present the design, growth, fabrication and characterization of our white hybrid nanocrystal-LEDs that incorporate combinations of (1) yellow nanocrystals (λPL = 580 nm) on a blue LED (λEL = 440 nm) with (x,y) = (0.37,0.25), Tc = 2692 K and Ra = 14.69; (2) cyan and red nanocrystals (λPL = 500 and 620 nm) on a blue LED (λEL = 440 nm) with (x,y) = (0.37,0.28), Tc = 3246 K and Ra = 19.65; (3) green, yellow and red nanocrystals (λPL = 540, 580 and 620 nm) on a blue LED (λEL = 452 nm) with (x,y) = (0.30,0.28), Tc = 7521 K and Ra = 40.95; and (4) cyan, green, yellow and red nanocrystals (λPL = 500, 540, 580 and 620 nm) on a blue LED (λEL = 452 nm) with (x,y) = (0.24,0.33), Tc = 11 171 K and Ra = 71.07. These hybrid white light sources hold promise for future lighting and display applications with their highly adjustable properties.

Violet to deep-ultraviolet InGaN∕GaN and GaN∕AlGaN quantum structures for UV electroabsorption modulators

“…For QEM-2, QEM-3, and QEM-4, the growth temperatures of 705, 710, and 720°C are used, respectively, which tunes the amount of In incorporation and thus the absorption band edge ͑i.e., the operating wavelength͒, as also studied in our previous work. 15,16 The epitaxial growth is monitored at all times by in situ optical reflectance, and the growth temperature is further controlled using two infrared pyrometers. For QEM-2, we only grow 4 nm thick Mg doped p-type contact layer.…”

Self-consistent computation of electronic and optical properties of a single exciton in a spherical quantum dot via matrix diagonalization method

“…These effects provide different advantages in designing new generation electronic and optical devices including QD infrared photodetectors, light emitting diodes, and optical memories. [4][5][6] Because the semiconductor quantum structures have a great potential for device applications, their exciton mechanisms are widely investigated both theoretically and experimentally in condensed matter physics and applied sciences. [7][8][9][10][11][12][13][14][15][16][17][18] The electronic structure calculations of excitons are key to understanding the resulting optical properties and designing functional nanodevices.…”

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

“…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.…”