Abstract:
This work focused on studying the effect of
cadmium sulfide (CdS) interfacial layer on the performance
of titanium dioxide (TiO2)/poly (3-hexylthiophene) (P3HT)
solar cells and finding out its effect on charge recombination
dynamics of hybrid TiO2/P3HT solar cells. FESEM images
confirm the uniform distribution of chemical bath deposited
CdS layer on TiO2 nanoparticles. Insertion of CdS layer at
the nanocrystalline TiO2/P3HT interface broadens quantum
efficiency spectrum of the solar cells with peak values over
80 and 40 % at the wavelengths of maximum absorption of
CdS and P3HT respectively and hence enhances short-circuit
current density (JSC) from 3.5 to 5.9 mAcm-2 under
simulated illumination (70 mWcm-2
) with an AM 1.5 filter.
CdS layer further improves open circuit voltage (VOC) from
0.35 to 0.57 V, which is consistent with higher built-in
voltage in CdS/P3HT than in TiO2/P3HT due to relatively
lower laying conduction band edge of CdS. Photovoltaic
transient measurements show that the carrier life-time in
TiO2/CdS/P3HT solar cell is an order of magnitude longer
than that in TiO2/P3HT solar cell. Optimized TiO2/P3HT
solar cells with CdS interlayer yield power conversion effi ciencies over 1.5 %, which is three times greater than that for
similar solar cells without CdS layer.
