Hydrothermal growth of Zn5(OH)6(CO3)2 and its thermal transformation into porous ZnO film used for dye-sensitized solar cells
Hidrotermalna rast Zn5(OH)6(CO3)2 s termično transformacijo v porozno plast ZnO, uporabljeno za elektrokemijske sončne celice

english

2011

volume 45, issue 3

Inštitut za kovinske materiale in tehnologije
(Obvezni izvod spletne publikacije)

Zinc oxide (ZnO) films, composed of nano-sheets, were prepared by the thermal decomposition of hydrozincite film precursor (Zn5(OH)6(CO3)2, ZnHC). The ZnO film kept the morphology on the microscale level during the heat treatment, while the thermal decomposition caused the formation of a nano-porous structure of the nano-sheets' surface. ZnHC precursor was hydrothermally synthesized on the conductive glass from zinc nitrate and urea. The influence of media (water or mixture of water/ethylene glycol), PVP-K additive and the concentration of the initial reagents, on the morphology of the film were observed. The growth and morphology of the ZnHC film was followed with FE-SEM microscopy and the formation mechanism of the ZnHC film, formed in the water, was proposed. The assumed growth mechanism follows the concept of a self-assembling mechanism of the nanometer-sized building units into nano-sheets of ZnHC with a thickness of "20 nm. These nano-sheets are further agglomerating into porous film. The thickness of the film was around (5, 8, 10 and 20) mum after (2, 3, 4 and 24) h of synthesis, respectively. The addition of PVP-K and ethylene glycol retards the growth of ZnHC film. Moreover, the addition of PVP-K affects the interactions between particles and the substrate, which enable the parallel growth of the nano-sheets on the substrate surface. As prepared ZnO films were used for DSSCs, where the conversion efficiency was "0.6 %.

14.08.2012