Work

Towards the Removal of HMTA Molecules in the Chemical Bath Deposition of ZnO Nanowires

Year: 2025

Type: article

Abstract: The chemical bath deposition of ZnO nanowires is of high interest for many functional devices, but the typical use of hexamethylenetetramine (HMTA) molecules forming formaldehyde as a harmful substance raises health, environment, and regulation issues. After a careful review of the multiple roles of HMTA molecules, we unambiguously show, using X-ray near-edge structure absorption spectroscopy with synchrotron radiation, that they do not form any complexes with the Zn(II) species, both in the low- and high-pH regions. In contrast and in agreement with thermodynamic computations, [Zn(H2O)6]2+ and Zn(NH3)42+ ion complexes are revealed to be the predominant Zn(II) species in the low- and high-pH regions. The use of HMTA molecules is found to be critical to form ZnO nanowires with a high aspect ratio in the low-pH region. In contrast, HMTA molecules are shown to be fully substituted by ammonia in the high-pH region to form ZnO nanowires with a high structural and optical quality. The removal of HMTA molecules for the chemical bath deposition of ZnO nanowires in the high-pH region represents a significant step forward towards the development of a chemical synthesis fully compatible with green chemistry.

Source: Nanomaterials

DOI: 10.3390/nano15201574

Authors: Adrien Baillard, Estelle Appert, Fabrice Wilhelm, Eirini Sarigiannidou, Vincent Consonni

Institutions: Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Laboratoire des Matériaux et du Génie Physique, Université Grenoble Alpes, European Synchrotron Radiation Facility

Language: English

Topic: ZnO doping and properties

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,896

Funder: Agence Nationale de la Recherche