Influence of anneal time and ZnO nanorod on the efficiency of organicinorganic hybrid solar cell

Abstract

In this study, we investigated the effect of annealing time and morphology of ZnO nanorods on the conversion efficiency of hybrid solar cell. ZnO nanorods were synthesized by two-step electrochemically steady stream method. The result showed the uniform growth of nanorods which have a good orientation in demonstrating the hexagonal structure with an average diameter from 30nm to 50nm and average length from 200nm to 250nm. P3HT : PCBM (1:1) conductive polymer blend was also fabricated by spin coating method at 400 rpm and incubated during 10 minutes, 20 minutes, 30 minutes and 60 minutes in nitrogen environment at 130⁰C. UV-Vis spectrashowed the high photon absorption in the visible light wavelengths with three characteristic peaks at of 515nm, 555nm and 610 nm. With the annealing time of 30 minutes, the highest absorption was reached with the increasing crystallization ofP3HT: PCBM film and thereby the conversion efficiency of the cell was enhanced. Especially, the presence of ZnO nanorods in the system using and without using PEDOT: PSS has showed significantly the enhancement of conversion efficiency of solar cells as compared to the system cell using ZnO film. And conversion efficiency of our device has increased from 0.92 % to 1.23 % (for system without PEDOT: PSS) and from 1.38 % to 1.43 % (for system with PEDOT : PSS layer).