A novel approach to large bandgap semiconductor materials design is demonstrated. Based on a thermodynamical growth control concept, a low temperature aqueous thin film growth technique is presented to produce, at large scale and low cost, novel metal oxide-based nano- to micro-structures. Three-dimensional arrays consisting of building blocks of controlled morphologies, sizes and orientations, engineered from molecular to nano-, meso- or microscopic scales are generated onto various substrates. Semiconductor technology and in particular, photovoltaics and photocatalysis, shall be beneficiary of such designed arrays. Promising improvements in terms of overall efficiency and manufacturing costs as well as better fundamental understandings of their electronic structure are foreseen with the use of such purpose-built materials. To cite this article: L. Vayssieres, C. R. Chimie 9 (2006) .