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Quantum sensors have notably advanced high-sensitivity magnetic field detection. Here, we report quantum sensors constructed from polarized spin-triplet electrons in photoexcited organic chromophores, specifically focusing on pentacene-doped para-terphenyl $(\approx 0.1\%)$. We demonstrate essential quantum sensing properties at room temperature (RT): optically generated electronic polarization and state-dependent fluorescence contrast by leveraging differential pumping and relaxation rates between triplet and ground states. We measure high optically detected magnetic resonance contrast $\approx 16.8\%$of the triplet states at RT, along with long coherence times under spin echo and Carr-Purcell-Meiboom-Gill (CPMG) sequences, $T_2=2.7\mu \mathrm{s}$and $T_2^{\text{DD}}=18.4\mu \mathrm{s}$, respectively, limited only by the triplet lifetimes. The material offers several advantages for quantum sensing, including the ability to grow large (cm scale) crystals at low cost, absence of paramagnetic impurities, and electronic diamagnetism when not optically illuminated. Utilizing pentacene as a representative of a broader class of spin triplet- polarizable organic molecules, this paper highlights the potential for quantum sensing in chemical systems. 

Abstract We incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS (⁺NH₃(CH₂)₂Se⁻), which occupies both the X⁻and A⁺sites in the prototypical ABX₃perovskite. The new organoselenide‐halide perovskites: (SeCYS)PbX₂(X=Cl, Br) expand upon the recently discovered organosulfide‐halide perovskites. Single‐crystal X‐ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide‐halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid‐state⁷⁷Se and²⁰⁷Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX₂largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable band gap decrease. Optical absorbance measurements indeed show band gaps of 2.07 and 1.86 eV for (SeCYS)PbX₂with X=Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the band gap from 1.86 to 2.31 eV–straddling the ideal range for tandem solar cells or visible‐light photocatalysis. The comprehensive description of the average and local structures, and how they can fine‐tune the band gap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid‐state and organo‐main‐group chemistry. 

Lithium transference in a multivalent electrolyte containing bulky, star-shaped anions is compared using three experimental techniques, namely, electrochemical polarization, PFG-NMR and electrophoretic NMR. 

Nanoparticle organic hybrid materials (NOHMs) have been proposed as excellent electrolytes for combined CO₂capture and electrochemical conversion due to their conductive nature and chemical tunability. However, CO₂capture behavior and transport properties of these electrolytes after CO₂capture have not yet been studied. Here, we use a variety of nuclear magnetic resonance (NMR) techniques to explore the carbon speciation and transport properties of branched polyethylenimine (PEI) and PEI-grafted silica nanoparticles (denoted as NOHM-I-PEI) after CO₂capture. Quantitative¹³C NMR spectra collected at variable temperatures reveal that absorbed CO₂exists as carbamates (RHNCOO⁻or RR′NCOO⁻) and carbonate/bicarbonate (CO₃²⁻/HCO₃⁻). The transport properties of PEI and NOHM-I-PEI studied using¹H pulsed-field-gradient NMR, combined with molecular dynamics simulations, demonstrate that coulombic interactions between negatively and positively charged chains dominate in PEI, while the self-diffusion in NOHM-I-PEI is dominated by silica nanoparticles. These results provide strategies for selecting adsorbed forms of carbon for electrochemical reduction. 

We demonstrate that contrary to previous reports, transference number decreases with increasing degree of polymerization in non-aqueous lithium-bearing polyelectrolyte solutions that have been proposed as next-generation battery electrolytes.