Influence of corona poling on ZnO properties as n-type layer for optoelectronic devices

Corona poling effects on optical and structural characteristics of zinc oxide (ZnO) thin films prepared by sol–gel spin coating technique were investigated. Atomic force microscope study showed the formation of pyramidal grains structure on the Corona-treated surface. The green–yellow photoluminescence peak centered at 2.36 eV and correlated to the antisite oxygen O(Zn) defect, was found to decrease. X-ray diffraction patterns demonstrated that the Corona treatment enhanced the polycrystalline nature and increased the grain sizes of the ZnO thin films, which was also beneficial for electron transport. The role of the surface roughness of the ZnO thin film as electron transport layer in determining the photovoltaic effect of the inverted solar cells (ISCs) was examined by fabricating ISCs based on P3HT/PC(61)BM. The power conversion efficiency (PCE) obtained from these fabricated ISCs increased from 3.05 to 3.34%.