Fig. 1: A system architecture and design procedure of multi-primary coloured lighting system with patterned QD-LEDs. | Nature Communications

Fig. 1: A system architecture and design procedure of multi-primary coloured lighting system with patterned QD-LEDs.

From: Optoelectronic system and device integration for quantum-dot light-emitting diode white lighting with computational design framework

Fig. 1

a N-primary coloured lighting system. N is the number of primary colours; Λ = (λ1, λ2, …, λN) is a set of peak wavelengths (λi), w = (w1, w2, …, wN) is a set of emission widths (wi), and A = (A1, A2, …, AN) is a set of peak radiances (Ai) for i-th QD pattern. P is the pitch of the pixel group. ETL electron transport layer, EML emissive layer, HTL hole transport layer, HIL hole injection layer. b An emission spectrum of white lighting system to be optimised by the colour optimisation process. D65 is a normalised power distribution of the CIE D65 standard illuminant, and L is a power distribution of any given white lighting system. β = (β1, β2, …, βN) is a set of peak powers (βi) normalised for the D65 power distribution. c Exampled CRI values of a given emission spectrum over the test colour samples (TCSs). CRIa is the average CRI of TCSs from 1 to 8. d Reflectance spectra of 14 TCSs. e Chromaticity difference Δxy from the CIE D65 illuminant. f A stratified layer structure of a monochromatic QD-LED device used in the charge transport simulation. z spatial variable, tEML thickness of EML. g A flat-band energy-level diagram across the device with respect to the distance from the anode electrode. ITO indium tin oxide, TFB Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4’-(N-(4-sec-butylphenyl)diphenylamine)], QDs quantum dots, MZO magnesium-doped zinc oxide, Al aluminium. PEDOT:PSS is a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate). Jpd, Jnd, Jpi, Jni, Jpt, and Jnt are drift-diffusion, injection, and tunnelling current densities for holes (subscript p) and electrons (subscript n). RRAD is a radiative recombination rate per unit area. h Hole and electron density distributions for the applied voltages. i Simulated voltage dependencies of hole density (pQD), electron density (nQD), and RRAD at QD layer. j Schematic illustration of the emission peak adjustment by changing pattern widths. Ai* is adjusted peak radiance of i-th QD pattern. Insets are the emission pattern layouts of the devices with identical emission widths and different emission widths.

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