CubaGREEN project aim is the development of the synthesis of ternary semiconductors at the nanoscale and of innovative characterization methods of structure, morphology and size of nanocrystals, in order to derive fundamental information, from the atomic to the nanometer scale.
Within the framework of the project combined X-ray scattering methods will be developed and applied to characterize colloidal nanocrystals I-III-VI2 (I = Cu+, III = Al3+, Ga3+, In3+, e VI = S2-, Se2-, Te2-). These materials are very promising for optoelectronic and photovoltaic applications, as "green" alternative to the conventional Pb-and Cd- based semiconductors. However the origin of their promising properties it is still unclear, as well as their correlation with structural and compositional parameters.
The aims of CubaGREEN are:
i) developing and implementing innovative experimental and computational methods for the structural and microstructural characterization of nanocristalline materials, based on the synergic combination of Small and Wide- Angle X-ray Total.
ii) Applying the developed methodologies for the atomic-to-nanometer scale characterization of colloidal I-III-VI2 (I = Cu+, III = Al3+, Ga3+, In3+, e VI = S2-, Se2-, Te2) semiconductors, characterized by a large compositional and structural variety. These materials represent ideal systems for the development and optimization of the analytical methods described at i) for both their complexity (thus highlighting the full potential of the method) and their relevance as functional materials.
The project will be developed in three steps:
1) syhthesis of colloidal semiconductors at the nanoscale of general formula I-III-VI2 (I = Cu+, III = Al3+, Ga3+, In3+, e VI = S2-, Se2-, Te2), by exploring different crystalline phases and composition and employing hot-injection and heat-up methods, allowing a strict control over nanocrystals size and shape. Conventional characterization techniques will be applied.
2) Design and implementation of Small- (SAXS) and Wide angle (WAXS) X-ray total scattering experiments, on the colloidal suspensions synthesized at 1), to be performed at the Aarhus University Laboratories (SAXS) and Synchrotron sources (WAXS).
3) Development of algorithm and computational models for the combined modeling of SAXS and WAXS data collected.
The results that CubaGREEN will accomplish are:
i) definition of experimental and computational methodologies, based on X-ray scattering methods, for the structural and microstructural characterization of materials at the nanoscale.
ii) Characterization of atomic to nanometer scale properties of ternary I-III-VI2 semiconductors, in particular related to their structural and compositional defectiveness, size and morphology.
iii) Correlation of their structural properties with the peculiar optoelectronics properties of these materials, in order to evaluate the role of structural defects, composition and size modifications on them. This result is of paramount importance in order to drive future synthetic approaches and promote this innovative class of materials as "green" alternatives to Pb- and Cd- based nanomaterials.