Colloidal Ni1−xCoxO nanostructures as anodic buffer layers in hybrid polypyrrole/Zn1−yInyO p–n junctions

Abstract

The availability of a wide array of colloidal organic/inorganic nanostructures has opened up an interface to establish highly innovative and attractive hybrid materials for a number of optoelectronic applications recently. In this regard, a colloidal route has been established to fabricate hybrid photodiodes and study the influence of Ni_1−xCo_xO colloids as anodic buffer layers in them. The buffer oxide nanostructures were established through a facile surfactant free wet chemical approach with a cubic phase. Their absorbance properties were found to be influenced by the charge transfer process taking place between the O²⁻ and Co²⁺ ions, while the vibrations corresponding to Co ions in between the tetrahedral and octahedral sites were found to be predominant in the Raman spectroscopy measurements. Hybrid p–n junctions were fabricated over the chemically in situ polymerized polypyrrole deposits using n-Zn_1−yIn_yO and p-Ni_1−xCo_xO colloidal nanostructures through a drop casting methodology. The structural properties and distribution of the hybrid nanostructures across the heterostructures were perceived through Raman and scanning electron microscopy. The electrical properties of the fabricated hybrid heterostructures were assimilated using I–V characteristics, which revealed the interfacial anodic buffer layers to improve the charge selectivity across the corresponding electrodes by acting as efficient hole transporting layers (HTL) and blocking the flow of electrons.