The Effect of Structural Properties of Cu₂Se/Polyvinylcarbazole Nanocomposites on the Performance of Hybrid Solar Cells

Abstract

It has been said that substitution of fullerenes with semiconductor nanocrystals in bulk heterojunction solar cells can potentially increase the power conversion efficiencies (PCE) of these devices far beyond the 10% mark. However new semiconductor nanocrystals other than the potentially toxic CdSe and PbS are necessary. Herein we report on the synthesis of Cu2Se nanocrystals and their incorporation into polyvinylcarbazole (PVK) to form polymer nanocomposites for use as active layers in hybrid solar cells. Nearly monodispersed 4 nm Cu2Se nanocrystals were synthesized using the conventional colloidal synthesis. Varying weight % of these nanocrystals was added to PVK to form polymer nanocomposites. The 10% polymer nanocomposite showed retention of the properties of the pure polymer whilst the 50% resulted in a complete breakdown of the polymeric structure as evident from the FTIR, TGA, and SEM. The lack of transport channels in the 50% polymer nanocomposite solar cell resulted in a device with no photoresponse whilst the 10% polymer nanocomposite resulted in a device with an open circuit voltage of 0.50 V, a short circuit current of 7.34 mA/cm2, and a fill factor of 22.28% resulting in a PCE of 1.02%.

Effect of nanocrystals concentration on optical and luminescent properties of PVK:ZnSe nanocomposites

“…The luminescence peaks are assigned to PVK as the excitation energy is lower that used for the excitation of ZnSe nanoparticles. No new emission peaks have been observed in the luminescence spectra of this system, however, the new peaks related to nanoparticles in Cu 2 Se/PVK system were reported by Govindraju et al [27]. The luminescence has been found to increase up to 70 wt.% of ZnSe nanoparticles addition in the nanocomposites, while further addition of the nanoparticles resulted in some decrease in the luminescence intensity.…”