Heterostructured semiconducting quantum dots (QDs) have stable physical properties that make them interesting candidates for nu-merous applications in optical sensing, pho-tocatalysis and solar photovoltaics. When exposed to light, the delocalization of their photoelectrons into the outer shell improves their catalytic capabilities, as well as the con-version of optical energy into electrical cur-rent. This presentation will focus on colloidal core/shell QDs with tunable shell and core thicknesses. Their morphology, bandgap structures, photoluminescence, photo-electrical and photo-chemical properties are investigated by advanced characterizations based on transmission electron microscopy, x-ray photoelectron spectroscopy and time-resolved photoluminescence measurements, for solar energy conversion in photoelectro-chemical (PEC) and photovoltaic (PV) cells. Using specific ion-beam treatments to control the concentration of structural defects gener-ated inside the different regions of the QDs, it is shown that the presence of non-radiative centers in their outer part promotes the gener-ation of photocurrent, through enhanced cur-rent linkages exacerbating the release of pho-toelectrons. This feature is attributed to the occurrence of a spacially-assisted charge car-rier separation, resulting from the delocaliza-tion of the photo-electrons over the whole conduction band of the core-shell system. In addition to provide physical insight regarding the charge carrier exchanges, bandgap align-ment and electron dynamics (Figure 1), the exciton dissociation based on wavefunction engineering and the implementation of post-growth processes aiming to enhance charge transfers are found to increase the solar ener-gy conversion, which makes such an ap-proach relevant for the development of new nanomaterials with superior performance.
References
G. S. Selopal, H. Zhao, X. Tong, D. Benetti, F. Navarro Pardo, D. Barba, F. Vidal, Z., M. Wang, F. Rosei, Advanced Functional Materials, 1701768 (2017).
C. Wang, D. Barba, G. S. Selopal, H. Zhao, J. Liu, H. Zhang, F. Rosei, Ad-vanced Functional Materials, 1904501 (2019).
H. Zhang, L. V. Besteiro, J. Liu, C. Wang, G. S. Selopal, Z. Chen, D. Barba, Z. M. Wang, H. Zhao, G. P. Lopinski, S. Sun, F. Rosei, Nano Energy 79, 105416 (2021).

Dr. D. Barba is senior researcher at INRS since 2014 and coordinator of the UNESCO MATECSS chair dedicated to advance materials for energy conversion and storage. He held his PhD in physics from the Univerity of Sherbrooke (Canada) in 2003. His recent research activities are focusing on nanostruc-tured semiconductors for applications in pho-tonics, optoelectronics and photovoltaics. Dr. Barba also remains strongly involved in the area of ion implantation for advanced materi-al synthesis, matter modification and analysis, optical spectroscopies, as well as space tech-nologies