Tyagi, Priyanka and Srivastava, Ritu and Kumar, Arunandan and Tuli, Suneet and Kamalasanan, M. N. (2013) Study of shifting of recombination zone in multi-emissive layer organic light emitting devices and its effect on color stability. Journal of Luminescence , 136. pp. 249-254. ISSN 0022-2313

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Abstract

Color stability in multi-emissive layer organic light emitting devices (Me-OLEDs) has been investigated. Me-OLEDs were based on multiple emitters with a common host CBP doped with three dopants, BCzVBi, Ir(ppy)(3) and Ir(btp)(2)acac for blue, green and red emission. A major variation in CIE coordinates were found from (0.312, 0.294) to (0.236, 0.267) with increase in voltage from 6 to 9 V. This coordinate. shift in Me-OLEDs has been attributed to the shifting of recombination zone with increase in voltage. In order to support our experimental observation, the EL spectrum of Me-OLEDs has been expressed as a linear combination of EL intensities of OLEDs with its individual constituting layers as emitters. In this way, the contribution of each layer in the EL spectrum of Me-OLEDs has been evaluated at each voltage. It has been observed from these calculations that the contribution of red emitter decreases from 47% to 33.33% and blue emitter increases from 38% to 51.67% with the increase in voltage from 6 to 9 V. This supports our hypothesis of shifting of recombination zone with the change in voltage. This shifting has been attributed to the field dependency of electron mobility in CBP. Me-OLED with CBP layers between the emitters was fabricated to improve the color stability. Significant improvement in color stability was achieved without changes in current efficiency in Me-OLED with interlayers.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s Elsevier.
Subjects:	Optics
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	03 Jun 2020 11:13
Last Modified:	03 Jun 2020 11:13
URI:	http://npl.csircentral.net/id/eprint/3025

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