Electro Deposition of CNT and Fullerene thin films:

We have used 0.1% and 0.2% solution of fullerene (C60) and carbon nano-tubes (multi-walled and single-walled) individually in methanol for thin film deposition. Silicon substrate of area 0.66cm2 is mounted on the negative electrode. The distance between the substrate and positive electrode was set to 1cm. Change in the current density as a function of applied potential was observed with different percentage of graphitic material. Current densities are measured in the voltage range of 100V~600V for fullerene and MWCNT; a voltage range of 50V~340V is used for SWCNT. Then electro deposition was done for 1 hour. During deposition, the current density was maintained at a fixed value of 3.3766mA/cm2 by varying voltage. Current density increases with increasing percentage of graphitic material in solution. Film deposited from 0.2% concentrated solution of SWCNT had the greatest percentage change of current density. pH of various solutions before and after deposition has been analyzed and got increase in pH.

SEM micrograph: SEM revealed the formation of thin film on Si. TEM with very high resolution is needed for better analysis.

FTIR: FTIR observation revealed peak at 2850 cm-1 and 2950 cm-1 which prove the existence of sp2 and sp3 bond, characteristic of fullerene and CNT. A prominent peak at 1531 cm-1 presumably attributed to C-H bond of methanol solution. N-H bond of Amine compound remains as a second probability.

UV-vis spectroscopy: UV-vis. spectrescopy performed to observe the transmission, reflectance and absorption. Optical bandgap has been measured. High absorption (75%) for a band of frequency (400nm-1000nm wavelength) proves the utility of SWCNT in solar cell.

Raman Spectroscopy: Recently, we have also performed the Raman spectroscopy to observe the intrinsic material properties.

Lab: Semiconductor Technology Research Center, Center for Advanced Research in Sciences, Dhaka University and Process Development Lab, BCSIR.

I worked on deposition (through electro-deposition, spin coating and dip coating) and structural and optical characterization (AFM, FESEM, EDX, XRD, FT-IR, UV –Visual spectroscopy) of SWCNT, MWCNT and Fullerene thin films.

Our Future Plan was:

All- CNT Solar Cell

• We have a plan for fabricating an all-CNT solar cell as: p-SWCNT-ALD Al2O3 -n SWCNT on PMMA in a collaboration with TIFR
• We will also explore the viability of MWCNT in solar cell with p-MWCNT-SiO2-n Si on PMMA