This presentation will be devoted to the design by molecular or soft chemistry approaches of hybrid

organic-inorganic semiconductors based on ZnO or even purely organic (g-C3N4) for applications in LED

lighting [1] or photocatalytic reduction of CO2 [2,3] or N2 [4], respectively. Although the application

areas are very different, the common link of these application areas is to find the experimental

conditions for electron availability via light activation and their selective use for the targeted

application. But beyond this source of electrons, it is the whole system that must be thought and

optimized to aim for the best performances but also to consider questions in terms of use on an

industrial scale and recycling.

Firstly, we will address the elaboration of SiO2@ZnO-PAAH core-shell structures via Sol-Gel coating to

achieve remarkable PLQY up to 64%. [4] (Fig. 1A). We will also demonstrate how this silica shell could

be used to improve their compatibility with the silicone resin to develop a prototype combining a cold

color temperature (CCT = 6660K) and a color rendering index (CRI) of 90 (Fig.1B). This technical

performance is unprecedented compared to current products on the market, as a high CCT is usually

associated with a low CRI.

Secondly, we will discuss the impact of these different parameters on the efficiency of CO2 or N2

reduction by photocatalysis in ionic liquids (IL) media based on imidazolium. We will show how

isopropanol has proven to be an excellent co-solvent but also how the ratio of isopropanol and thus

the ratio of ionic liquid changes the reaction mechanism from a heterogeneous to a homogeneous

photocatalytic system. We will also show that the presence of water but also of co-products such as

acetic acid and thus the pH, for the aqueous system, has a very strong impact on the efficiency of the

system. In conclusion, we will present the different scenarii and mechanisms involved either in a

concentrated IL medium or in an IL medium diluted in water or in isopropanol and the need to employ

a photocatalyst or not.

[1] Y. Zhang, T. Gard, C. Theron, A. Apostoluk, K. Masenelli-Varlot, B. Canut, S. Daniele, B. Masenelli,

Applied Surface Science 2021, 540 (1), 148343

[2] Y. Peng, K. C. Szeto, C. Santini, S. Daniele, ChemPhotoChem 2021, 5, 721-726

[3] Y. Peng, K. C. Szeto, C. Santini, S. Daniele, Chem. Eng. J. Adv. 2022, 12 100379

[4] N. Zhang, K. C. Szeto, M. Tiano, C. Santini, S. Daniele, unpublished results