Interface Modification for Enhancing the Conduction Mechanisms in 2,2’,7,7’-Tetrakis(N,N-Diphenylamine)-9,9’-Spir Obifluorene (Spiro-TAD) Nano Layers for Optoelectronic Applications
Omwati Rana1, Ritu Srivastava2, M.N. Kamalasanan3, M. Husain4, M. Zulfequar5
1Omwati Rana, Department of Physics, Daulat Ram College, University of Delhi and Advanced Materials and Devices Division, CSIR-National Physical Laboratory and Jamia Millia Islamia, Jamia Nagar, New Delhi, India.
2Ritu Srivastava, Department of Physics, Daulat Ram College, University of Delhi, India
3M.N.Kamalasanan, Department of Physics, Daulat Ram College, University of Delhi, India
4M.Husain, Advanced Materials and Devices Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi, India
5M.Zulfequar, Advanced Materials and Devices Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi, India
Manuscript received on 26 March 2019 | Revised Manuscript received on 07 April 2019 | Manuscript Published on 18 April 2019 | PP: 857-863 | Volume-7 Issue-6S March 2019 | Retrieval Number: F03730376S19/2019©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Hole transport properties of 2,2’,7,7’-tetrakis(N,N-diphenylamine)-9,9’-spirobifluorene (Spiro-TAD) have been analyzed by studying the J-V characteristics of hole only devices at different temperatures and nano layer thicknesses of Spiro-TAD in the devices. The conduction processes were understood by using Richardson Schottky (RS) thermionic model and found injection limited behaviour. When an optimised nano layer of F4TCNQ was inserted between the organic layer and metal electrodes, the injection energy barrier at metal/organic interface was found to reduce significantly. By the optimised nano layer of F4TCNQ, completely removal of interface barrier is possible. It has been observed that the J-V characteristics of interface modified devices were well fitted through space charge limited conduction (SCLC) with electric field and temperature dependent charge carrier mobility model. The obtained values of hole mobility by varying electric field and temperatures were well fitted with both Gill’s model as well as Gaussian disorder model within the experimental accuracy. Mobility parameters obtained from J-V measurements were comparable to those reported from Time of flight (TOF) technique and field effect transistors (FETs) measurements. These results show that it is possible to tune the conduction mechanism in various optoelectronic devices by modifying their interfaces and remove interface barriers which are detrimental to the efficiency and stability of these devices.
Keywords: Charge Transport; Injection Limited Conduction; SCLC; Hole Mobility; Gills Model; Gaussian Disorder Model.
Scope of the Article: Nanotechnology