In the last few years, perovskite solar cells (PSCs) became one of the most advanced technology in photovoltaics (PVs), reaching 25.5% certified power conversion efficiency (PCE) in single-junction cells. [1] This high-performance level, exceeding 80% of the thermodynamic bandgap limit of the perovskite, stems from the maximization of the solar spectrum absorption capability and reduction of the open-circuit voltage deficit through well-adjusted interfacial band level alignment and bulk/interface defects passivation to abate nonradiative recombination processes. [2] The reduction of interfacial energy losses due to energy misalignment is facilitated given the large richness of cationic and anionic substitution possibilities starting from the prototypical CH 3 NH 3 PbI 3 (MAPbI 3 ) composition, affording a very precise control of the optoelectronic characteristics. Through a wide exploration of composition, triple cation/double halide formulation Cs 0.05 (MA 0.17-FA 0.83 ) 0.95 Pb(Br 0.17 I 0.83 ) 3 (CsMAFA) rapidly emerged as one of the most efficient compositions for single-junction PSC [3,4] and also as a top cell in a monolithic perovskite/silicon tandem architecture reaching above 29% certified PCE with a slightly bromide richer composition. [5] However, the performance enhancement has progressed more rapidly than improving the stability, inhibiting the technology transfer to larger scale. Many efforts are now turned toward this objective through device encapsulation, [6,7] hydrophobic interfacial layers, [8] nanoscale 2D/3D structuration, [9] and defects passivation. [10][11][12][13] Topdown approaches that give further insights into the degradation pathways of the perovskite absorber and device stacks under operational conditions are highly desirable to propose rational ways to improve the stability at different scales from bulk and surface of the materials, interfaces, and finally on the entire device. Given the complexity in deciphering all possible contributions involved during the degradation, the first step ex situ investigations provide already relevant trends about material weaknesses. For instance, exposure of the conventional MAPbI 3 composition to a humid atmosphere showed rapid decomposition into PbI 2 and gas releases. [14] Depending on the relative humidity (RH)

In the growing context of sustainable chemistry, one of the challenges of organic chemists is to develop efficient and environmentally friendly methods for the synthesis of high-added-value products. Heterogeneous photocatalytic transformations have brought revolution in this regard, as they take advantage of an unlimited source of energy (solar light) or artificial UV light to onset organic chemical modifications. The abundance of free carbohydrates as chemical platform feedstock offers a great opportunity to obtain a variety of industrial interest compounds from biomass. Due to their chirality and polyfunctionality, the conversion of sugars generally requires multi-step protocols with protection/deprotection steps and hazardous chemical needs. In this context, several selective and eco-friendly methodologies are currently under development. This review presents a state of art of the recent accomplishments concerning the use of photocatalysts for the transformation and valorization of free carbohydrates. It discusses the approaches leading to the selective oxidation of free sugars, their degradation into organic chemicals, or their use for hydrogen production.