Rana, O. and Srivastava, R. and Chauhan, G. and Zulfequar, M. and Husain, M. and Srivastava, P. C. and Kamalasanan, M. N. (2012) Modification of metal-organic interface using F-4-TCNQ for enhanced hole injection properties in optoelectronic devices. physica status solidi (a), 209 (12). 2539-2545. ISSN 1862-6300

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Abstract

Incorporation of thin layers of tetrafluro-tetracyanoquinodi-methane (F-4-TCNQ) has been found to modify the work functions of a number of substrates. Surface potential measurement using Kelvin probe method (KPM) has been used to monitor the change in work function of the modified substrates. The results support the integer charge transfer model by which the Fermi levels of the substrates are aligned with the negative polaron states of F-4-TCNQ. Further, we found that the work function of the substrates increases with increase in F-4-TCNQ thickness from 0 to 7 nm and then saturates for further increase in thickness. The variation in work function has been attributed to the low surface coverage of F-4-TCNQ islands on the substrates. The ITO and Au substrates with increased work functions were used as the electrode for hole only devices of common hole transport materials. The hole injection property has been found to increase with increase in F-4-TCNQ thickness and for ITO surface modified with 7 nm F-4-TCNQ layer, ohmic conduction has been achieved for HTLs with HOMO level up to 5.4 eV. When these modified substrates were used as hole injecting contacts in organic light emitting diodes (OLEDs), they gave substantially higher electroluminance, power efficiency and lower operating voltages.

Item Type:	Article
Additional Information:	copyright for this article belongs to M/s Wiley-VCH Verlag
Subjects:	Materials Science Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	19 Aug 2026 11:08
Last Modified:	19 Aug 2026 11:08
URI:	https://npl.csircentral.net/id/eprint/3489

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