Electrochemically assembled planar hybrid poly(3-methylthiophene)/ZnO nanostructured composites

Step by step electrochemical assembling layers of compact ZnO (ZnOcomp), ZnO nanorods (ZnONR) and poly(3-methylthiophene) (P3MT) has been applied to form the photovoltaically active hybrid organic–inorganic heterostructure. Photoluminescence and photoconductivity characterization of the synthesized ZnOcomp and ZnONR layers display their different defect and doping states resulting in a non-linear I–V behavior of the assembled complex ZnOcomp/ZnONR layer structure for account of formation of a p–n junction at the interface. We find some healing of the defect states at surface of the ZnOcomp layer after its covering with ZnONR layer. The photoelectrochemical deposition of the stable P3MT on surface of the complex ZnOcomp/ZnONR structure is realized under light irradiation with wavelength close to near-band-edge (NBE) emission of ZnO (∼380 nm) when using the special mixed voltammetry–potentiostatic–galvanostatic mode. This mode is found to minimize overoxidation/degradation of the forming P3MT. After the synthesis the formed P3MT layer is electrochemically reduced to move it to a semiconductor state. The resulting hybrid ZnOcomp/ZnONR/P3MT heterostructure is photovoltaically active and displays open-circuit voltage about 0.45 V.

► PV active ZnO compact/ZnO nanorods/P3MT planar heterostructures were electrodeposited. ► The ZnO compact, and ZnO nanorod layers have different defect and doping states. ► The electrodeposition of ZnO nanorods over ZnO compact layer heals the defect surface states. ► The electrochemical deposition of P3MT on the ZnO surface was realized under UV irradiation. ► The mixed voltammetry–potentiostatic–galvanostatic mode minimizes P3MT overoxidation.