Institut des Sciences et Technologies Moléculaires d'Angers

The article establishes a new framework for the multimodal characterization of nanoparticles in the ultrahigh mass range. In this new framework, Taylor dispersion analysis (TDA) is integrated with in‐line optical absorbance spectroscopy and directly coupled to an electrospray ionization (ESI) interface. This configuration enables controlled transfer of analytes to charge detection mass spectrometry (CDMS), providing information about ion charge, mass, and optical properties. This innovative hyphenated setup is described using 60 nm gold nanoparticles, corresponding to a particle mass of ≈1.3 GDa, as a proof of concept. Taylorgrams obtained with analyte temporal diffusion monitoring by UV/vis spectroscopy and by CDMS are discussed in fame with numerical model and point out the associated challenges for size determination.

The precise engineering of surface-bound organic layers remains a central challenge in materials chemistry, particularly for the construction of mixed monolayers with tunable composition. While the electroreduction of diazonium salts produces robust, covalently anchored films, its inherent limitations - poor control over surface coverage and the lack of dynamic molecular exchange - frequently result in uncontrolled multilayer growth, complicating compositional tuning. In this study, we demonstrate that rational molecular design, specifically the incorporation of extended alkyl spacers, overcomes these limitations by enabling controlled co-immobilization of functional and diluent species and by promoting confinement of film growth to the monolayer regime. Using TEMPO as a model redox-active motif, we compare mixed layers derived from diazonium precursors with and without C12 spacers. Electrochemical characterization reveals that the presence of extended linkers enhances molecular organization, suppresses overgrowth, and enables predictable tuning of redox unit surface density simply by adjusting the composition of the functionalization solution. These results establish clear design principles for the controlled assembly of multifunctional organic interfaces and provide new insight into structure-reactivity relationships in diazonium-based surface modification.

Abstract The development of purely organic chiral room temperature phosphorescence (RTP) emitters is attracting more and more attention. However, the key parameters governing the polarized luminescence process remain difficult to predict and rationalize since the phosphorescence emission is rarely obtained in solution, hampering any structure‐relationship studies. To address this challenge, we report here the synthesis and chiroptical properties of a new family of metal‐free phosphorescent emitters based on phthalimide derivatives. Breaking symmetry of the phthalimide units and using intra‐ and intermolecular hydrogen bonding enable the obtention of circularly polarized (CP) RTP in solution with glum of up to 5 × 10−3. Interestingly, our investigations demonstrate the intricate role of hydrogen bonding interactions in modulating triplet state generation through the mixing of singlet and triplet states of different nature, i.e., n‐π* and π–π*, in the excited state, which is a crucial parameter for achieving intense CP‐RTP. These results bring additional molecular design guidelines to reach CP‐RTP in solution and additionally offer new insights into the subtle relationships between excited states of different spin multiplicity to reach higher CP phosphorescence intensity.

The development of purely organic chiral room temperature phosphorescence (RTP) emitters is attracting more and more attention. However, the key parameters governing the polarized luminescence process remain difficult to predict and rationalize since the phosphorescence emission is rarely obtained in solution, hampering any structure‐relationship studies. To address this challenge, we report here the synthesis and chiroptical properties of a new family of metal‐free phosphorescent emitters based on phthalimide derivatives. Breaking symmetry of the phthalimide units and using intra‐ and intermolecular hydrogen bonding enable the obtention of circularly polarized (CP) RTP in solution with glum of up to 5 × 10−3. Interestingly, our investigations demonstrate the intricate role of hydrogen bonding interactions in modulating triplet state generation through the mixing of singlet and triplet states of different nature, i.e., n‐π* and π–π*, in the excited state, which is a crucial parameter for achieving intense CP‐RTP. These results bring additional molecular design guidelines to reach CP‐RTP in solution and additionally offer new insights into the subtle relationships between excited states of different spin multiplicity to reach higher CP phosphorescence intensity.

Herein, a sustainable and eco‐friendly protocol is reported for the aerobic photochemical oxidation of boronic acids or esters, utilizing a dibenzothioxanthene imide as the photocatalyst at a very low catalyst loading (0.01%) in 2‐propanol, employing a 456 nm irradiation source. Additionally, this protocol is successfully applied to a variety of substrates.

We report herein the synthesis and characterization of azabenzannulated benzothioxanthene imides (BTIs) functionalized with various appended aromatic units. This new class of polycyclic aromatic hydrocarbons are prepared via a straightforward and efficient synthetic strategy that involves a visible-light-mediated photocyclization of imines. The later are formed in situ from the condensation of an amine moiety at the bay position of the BTI core with aldehydes, followed by oxidative rearomatization. These green-yellow fluorescent emitters (φf ~ 0.14-0.20) combine dual redox properties with significant triplet state generation — resulting from a combination strong spin-orbit couplings and the energetic proximity between their S1 state and their triplet states — with singlet oxygen sensitization efficiencies φΔ~ 0.39-0.49. Hence, this design principle enables accessible tailored structural modifications through the incorporation of diverse functional groups onto the BTI core with minimal synthetic effort, paving the way to original and versatile functional materials with broad potential in optoelectronics, biophotonics, and photodynamic therapy.

Development of a reproducible technique to grow large area single crystalline perovskite wafers is an open research gap in the field of single crystalline perovskite solar cells. A graphite-based localized heating technique for growing large area methylammonium lead bromide (CH3NH3PbBr3; MAPBr) single crystalline thin film (SCTF) on different buffer layers, such as glass/indium doped tin oxide (ITO), glass/ITO/poly(triaryl amine) (PTAA), and glancing angle deposition (GLAD) coated glass/ITO/TiO2 substrates is reported, and their charge transport properties are discussed. It is observed that the localized heating technique can confine the supersaturation of the precursor mainly to the center of the substrate, leading to a restricted number of nucleations within a specific area on the substrate. Here, such 2-3 seed crystals obtained initially are allowed to grow to a larger size of up to 65 mm2. The X-ray diffraction (XRD) analysis indicated that the large area SCTF is an actual single crystal and not a heterogeneous group of small crystals merged together with a crystallinity index (CI) of 92.60 ± 0.11% which was comparable to that of the bulk single crystal (97.74 ± 0.47%). The atomic force microscopy (AFM) image depicted a smooth SCTF surface (R a = 4.37 ± 0.01 nm), and the wave-like pattern is attributed to the substrate morphology, implying that the topography of the substrate plays a crucial role in obtaining a planar SCTF. The XRD, UV-visible, photoluminescence (PL), Raman, and FTIR spectra analyses revealed that the large area SCTF is phase pure and free of residual impurities. The charge injection characteristics of the SCTFs grown on different buffer layers were investigated using PL emission (PLE) and PL decay analyses. The decrease in the PLE intensity for the SCTFs grown on PTAA and TiO2 substrates implied exciton quenching behavior, indicating the injection of the photogenerated charge carriers into the charge transfer layers (CTLs). The decrease of the fast decay component from τ1 = 4.77 ± 0.18 ns for glass to τ1 = 3.32 ± 0.07 ns for TiO2 and τ1 = 3.15 ± 0.33 ns for PTAA is ascribed to the interfacial recombination of the charges accumulated at the CTL/perovskite interface. These results propose that the localized heating technique can be employed for growing large area single crystalline perovskite wafers for optoelectronic and photovoltaic device applications.