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Journal of Photonics for Energy • Open Access

Pyranylidene indene-1,3-dione derivatives as an amorphous red electroluminescence material
Author(s): Aivars Vembris; Martins Porozovs; Inta Muzikante; Valdis Kokars; Elmars Zarins

Paper Abstract

The organic light-emitting diode (OLED) has promising applications in flat-panel displays and novel light sources. Thus far, OLED structures have mostly been made by thermal evaporation in vacuum. An alternative approach is to use small molecules that form amorphous (glassy) structures from solutions. Such compounds can be used in ink-jet printing technologies and result in reduced OLED prices. We present an original red fluorescent organic compo-und 2-(2-(4-(bis(2-(trityloxy)ethyl)amino)styryl)-6-methyl-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK1), and its derivative 2-(2,6-bis(4-(bis(2-(trityloxy)ethyl) amino)styryl)-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK2), where the methyl group is replaced with a 4-substituted-styryl group. This change could improve the formation of glassy structures. The thickness of the electroluminescent layer in the device is optimized to the higher power efficiency and obtains: ITO/PEDOT:PSS (40 nm)/ZWK1 (95 nm)/LiF (1 nm)/Al (100 nm), and ITO/PEDOT:PSS (40 nm)/ZWK2 (85 nm)/LiF (1 nm)/Al (100 nm). The maximum of electroluminescence (EL) spectra for the device with the ZWK1 compound is 667 nm, which corresponds to the CIE coordinates x = 0.65 and y = 0.34. The power and luminance efficiency at a luminance of 100 cd/m2 is 0.63 lm/W and 1.78 cd/A, respectively. Adding an additional 4-substituted-styryl group to the ZWK1 molecule shifts the maximum of EL spectra to the red region (705 nm) and decreases the efficiencies by one order.

Paper Details

Date Published: 1 January 2011
PDF: 10 pages
J. Photon. Energy. 1(1) 011001 doi: 10.1117/1.3524819
Published in: Journal of Photonics for Energy Volume 1, Issue 1
Show Author Affiliations
Aivars Vembris, Univ. of Latvia (Latvia)
Martins Porozovs, Univ. of Latvia (Latvia)
Inta Muzikante, Univ. of Latvia (Latvia)
Valdis Kokars, Riga Technical Univ. (Latvia)
Elmars Zarins, Riga Technical Univ. (Latvia)

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