Nanostructured Inorganic and Organic Materials for Next Generation Solar-Based Energy Technology

The next generations of optoelectronic devices for energy production will have to comply with increasingly stringent requirements to promote sustainable development. The main directives concern efficiency, environmental compatibility and easy access on a global scale. In terms of materials, all this translates into the need for abundant, non-toxic, stable compounds with the best optoelectronic properties. An equally intriguing direction concerns the design of composite structures in which it is possible to combine the characteristics of several elements in order to exploit new functionalities. Among the most promising and widespread materials in various fields of optoelectronics we find the nanocrystals of transparent conductive oxides [1]. The advantages in the use of these nanomaterials derive from the successful convergence of optical transparency/absorption and conductivity and from the easy processability in solution for the formation of thin films. However, recent studies have opened new stimulating perspectives on the use of these metal oxides, especially in the field of light-powered devices. The possibility of increasing their charge density through photodoping makes these materials potential candidates for solar conversion technology, but also for energy storage [2,3]. Another family of compounds at the forefront of emerging energy applications are the quantum dots of graphene (GQD). In this case, their attractive optical and electronic properties come with a very low environmental impact and incredible versatility in terms of functionalization [4]. The synthetic control of these organic structures makes it possible to manipulate and enhance their photo-response and adapt them, for example, to the extraction of positive or negative charges on demand. In such a context, the subsequent charge transfer process is a key aspect in the improvement of the performance and possible multi-charge mechanisms can be a significant upgrade in materials design for advanced light-driven technologies as photovoltaics, photo-catalysis or photo-rechargeable batteries. In this study, we spectroscopically analyzed the behavior of Indium Tin Oxide nanoparticles with respect to the possible photo-induced charge accumulation. Furthermore, we present the potential charge transfer properties of these nanomaterials by means of chemical titration with an oxidizing compound (electron-acceptor) [5]. We extended the same characterization to some GQDs designed to be able to delocalize different charges. The aim of this work target the possible implementation and integration of both materials (creating, for example, composite hetero structures) and multiple charge transfer mechanisms (both electrons and holes) for the development of energy conversion and storage systems.<br/> <br/><b>References</b><br/>[1] T. Gatti et al. Adv. Energy Mater. 2021, 11, 2101041<br/>[2] I. Kriegel et al. Physics Reports 2017, 674, 1–52<br/>[3] M. Ghini, et al. Nanoscale Adv. 2021, 3, 6628-6634<br/>[4] L. Qianwen, et al. Mater. Chem. Front. 2020, 4.2, 421-436.<br/>[5] M. Ghini, et al. Nanoscale, 2021,13, 8773-8783