Modification of barrier height and depletion layer width of methyl red (MR) dye-based organic device in the presence of single-walled carbon nanotubes (SWCNT)

Abstract

In this paper, barrier height ( $$\phi_{{\text{b}}}$$ ) and depletion layer width (Wd) of ITO-coated glass/Methyl Red (MR) dye/Aluminum (Al)-based organic device have been studied, and effect of single-walled carbon nanotubes (SWCNT) on both of these parameters has been observed. ITO-coated glass as front electrode and Aluminum as back electrode are used to form the device by using spin coating technique. $$\phi_{{\text{b}}}$$ is calculated by analyzing both I–V and C–V characteristics. In the presence of SWCNT, $$\phi_{{\text{b }}}$$ is reduced from 0.870 ± 0.05 eV to 0.754 ± 0.05 eV in I–V characteristics and from 0.850 ± 0.12 eV to 0.784 ± 0.12 eV in C–V characteristics. $$\phi_{{\text{b }}}$$ is also estimated by Norde method, which shows the presence of SWCNT lowers the value of $$\phi_{{\text{b }}}$$ from 0.852 eV to 0.738 eV. Wd has been calculated from C–V characteristics. With SWCNT, value of Wd reduces from (8.74 ± 0.02) × 10−6 cm to (7.85 ± 0.02) × 10−6 cm. Threshold voltage also decreases from 2.52 V to 1.99 V in the presence of SWCNT. Addition of SWCNT within device ameliorates charge injection by lessening $$\phi_{{\text{b}}}$$ and Wd of the device.