Electrical characterization of Organic-Inorganic hybrid Solar Cell Material

Chandra M. S. Negi 1, Priyanka Rathore2, Gayatri Chauhan2, Ajay S. Verma2, Pyare Lal2, Saral K Gupta2,*

1Department of Electronics2 Department of Physics

School of Physical sciences Banasthali University, Rajasthan, 304022, India

Abstract Multiwall carbon nanotubes (MWCNT) doped poly (3-

hexylthiopene) (P3HT). Soluble MWCNT were dispersed in P3HT with the help of magnetic stirring.

The MWCNT dispersion in P3HTwas confirmed with help of field emission scanning electron microscope (FESEM) images.

Fabricated ITO/P3HT:MWCNT/Al Schottky diode structure. The electrical properties of fabricated device were

characterized by I-V measurement using Keithley source meter 2612.

The measured data were fitted with simulated I-V curve which explains the possible charge transport mechanism of the device.

Introduction

Organic solar cells that use polymers offers the possibility of low cost, less toxic manufacturing methods and the possibility of large area, light weight and flexible panels.

Polythiophenes have been the most widely used as donors, fullerenes have been the popular choices for acceptors. The high electric field at polymer/nanotube junction can split up the excitons, while the CNT can act as a pathway for the electrons.

Due to exceptional intrinsic properties of CNTs these are used in the polymers to fabricate nanocomposites. In particular, polymers doped with CNTs have exceptional potential for electronic device applications, such as photovoltaic cells.

Experimental Details Dispersion of MWCNTs in chlorobenzene (CB). Dispersion of MWCNTs with the help of ultrasonication method. Doping of P3HTwith MWCNTs with the help of magnetic stirring.

Thin Film FormationSpin coating method was used to deposit the thin film on ITO coated glass substrate

Device fabricationThree devices were formed with three different concentrations

1C = 60micro liter of base solution + 520 micro liter CB2C = 120micro liter of base solution + 480 micro liter CB3C = 180micro liter of base solution + 420 micro liter CBHere Base solution stands for dispersed MWCNTs in CB.

Fig.1. The schematic diagram of the device under study.

Fig.2. Energy band diagram of the device under study.

Results and discussion

Fig.3. FESEM image of dispersed MWCNTs.

I-V characteristics

0.01 0.1 1 1010-6

10-5

10-4

10-3

10-2

10-1

100

P3HT 1C 2C 3C

Cur

rent

Den

sity

(A/c

m2)

Voltage (V)

0.1 1 1010-5

10-4

10-3

10-2

10-1

100

ohmic

TCLC

Field dependent SCLC

Cur

rent

Den

sity

(A

/cm

2)

Voltage (V)

Experimental Simulation

Fig.4. I-V characteristics of the device for P3HT and P3HT doped MWCNTs at three different concentrations.

Fig.5. Comparison of the experimental and simulated I-V characteristics.

Conclusion

We have fabricated ITO/P3HT:MWCNT/Al Schottky diode structure, containing a blend of MWCNTs and P3HT at three different concentrations.

FESEM image confirm the dispersion of MWCNT in P3HT. The device in the presence of MWNCT shows dramatic

improvement in the current density. The fitted model explain that the current conduction

mechanism is neither purely Ohmic nor purely space charge limited in the electric field range used here, but follows the known behavior in organic semiconducting materials.

References

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