Managing emotions in the age of political polarization: A randomized controlled trial comparing mindfulness to cognitive reappraisal.

Emotional appraisals of political stimuli (e.g., videos) have been shown to drive shared neural encoding, which correspond to shared, yet divisive, interpretations of such stimuli. However, mindfulness practice may entrain a form of emotion regulation that de-automatizes social biases, possibly through alteration of such neural mechanisms. The present study combined a naturalistic neuroimaging paradigm and a randomized controlled trial to examine the effects of short-term mindfulness training (MT) (n = 35) vs structurally equivalent Cognitive Reappraisal training (CT) (n = 37) on politically-situated emotions while evaluating the mechanistic role of prefrontal cortical neural synchrony. Participants underwent functional near-infrared spectroscopy (fNIRS) recording while viewing inflammatory partisan news clips and continuously rating their momentary discrete emotions. MT participants were more likely to respond with extreme levels of anger (odds ratio = 0.12, p < .001) and disgust (odds ratio = 0.08, p < .001) relative to CT participants. Neural synchrony-based analyses suggested that participants with extreme emotion reactions exhibited greater prefrontal cortical neural synchrony, but that this pattern was less prominent in participants receiving MT relative to CT (CT > MT; channel 1 ISC = .040, p = .030).

Open for Bismuth: Main Group Metal-to-Ligand Charge Transfer.

The synthesis, characterization, and photophysical properties of 4- and 6-coordinate Bi3+ coordination complexes are reported. Bi(bzq)3 (1) and [Bi(bzq)2]Br (2) (bzq = benzo[h]quinoline) are synthesized by reaction of 9-Li-bzq with BiCl3 and BiBr3, respectively. Absorption spectroscopy, electrochemistry, and DFT studies suggest that 1 has 42% Bi 6s character in its highest-occupied molecular orbital (HOMO) as a result of six σ* interactions with the bzq ligands. Excitation of 1 at 450 nm results in a broad emission feature at 520 nm, which is rationalized as a metal-to-ligand charge transfer (MLCT) and phosphorescent emission resulting from bismuth-mediated intersystem crossing (ISC) to a triplet excited state. This excited state revealed a 35 µs lifetime and was quenched in the presence of oxygen. These results demonstrate that useful optoelectronic properties of Bi3+ can be accessed through hypercoordination with covalent organobismuth interactions that mimic the electronic structure of lead perovskites.

Binding Orientation of a Ruthenium-Based Water Oxidation Catalyst on a CdS QD Surface Revealed by NMR Spectroscopy.

We report on the binding of a Ru-based water oxidation catalyst (WOC) to CdS quantum dots (QDs) revealed by 1H NMR spectroscopy. Spin centers within the WOC exhibit correlated trends in chemical shift and T2 lifetime shortening upon QD binding. These effects are a highly directional function of proton position within the WOC, thus uncovering orientation information relative to the QD surface. The data suggest that the WOC interacts with the QD surface via the Ru terpyridine ligand, an unexpected orientation that has important implications for interfacial charge transfer and subsequent catalysis. This binding motif enables strong enough donor-acceptor electronic coupling for ultrafast photoinduced hole transfer while maintaining electronically distinct functional subunits.

Femtosecond Transient Absorption Spectra and Dynamics of Carrier Relaxation of Tin Perovskites in the Absence and Presence of Additives.

The effects of additives SnF2 (10%) and EDAI2 (1%) on the dynamics of carrier relaxation of formamidinium tin triiodide (FASnI3) perovskite were studied using femtosecond transient absorption spectra (TAS) with excitation at 600 and 870 nm. The TAS were analyzed according to a parallel sequential kinetic model with a global fit through singular-value decomposition. For excitation at 600 nm, two relaxation paths were found: one involved hot and cold carriers in the bulk state undergoing shallow bulk-defect-mediated charge recombination; the other involved trap carriers in the surface state undergoing deep surface-defect-mediated charge recombination. For excitation at 870 nm, only cold carriers were subjected to the bulk-state relaxation channel. Our spectral results indicate significant effects of the additives on retarding charge recombination in both bulk and surface states as well as decreasing the bandgap renormalization energy, the bandwidth of the photobleaching (PB) band, and the Stokes shift between the PB and photoluminescence bands, explaining how the device performance of FASnI3 solar cells became enhanced in the presence of SnF2 and EDAI2.

Relationships between Exciton Dissociation and Slow Recombination within ZnSe/CdS and CdSe/CdS Dot-in-Rod Heterostructures.

Type-II and quasi type-II heterostructure nanocrystals are known to exhibit extended excited-state lifetimes compared to their single material counterparts because of reduced wave function overlap between the electron and hole. However, due to fast and efficient hole trapping and nonuniform morphologies, the photophysics of dot-in-rod heterostructures are more rich and complex than this simple picture. Using transient absorption spectroscopy, we observe that the behavior of electrons in the CdS "rod" or "bulb" regions of nonuniform ZnSe/CdS and CdSe/CdS dot-in-rods is similar regardless of the "dot" material, which supports previous work demonstrating that hole trapping and particle morphology drive electron dynamics. Furthermore, we show that the longest lived state in these dot-in-rods is not generated by the type-II or quasi type-II band alignment between the dot and the rod, but rather by electron-hole dissociation that occurs due to fast hole trapping in the CdS rod and electron localization to the bulb. We propose that specific variations in particle morphology and surface chemistry determine the mechanism and efficiency of charge separation and recombination in these nanostructures, and therefore impact their excited-state dynamics to a greater extent than the heterostructure energy level alignment alone.

Observation of trapped-hole diffusion on the surfaces of CdS nanorods.

In CdS nanocrystals, photoexcited holes rapidly become trapped at the particle surface. The dynamics of these trapped holes have profound consequences for the photophysics and photochemistry of these materials. Using a combination of transient absorption spectroscopy and theoretical modelling, we demonstrate that trapped holes in CdS nanorods are mobile and execute a random walk at room temperature. In CdS nanorods of non-uniform width, we observe the recombination of spatially separated electrons and trapped holes, which exhibits a t-1/2 power-law decay at long times. A one-dimensional diffusion-annihilation model describes the time-dependence of the recombination over four orders of magnitude in time, from one nanosecond to ten microseconds, with a single adjustable parameter. We propose that diffusive trapped-hole motion is a general phenomenon in CdS nanocrystals, but one that is normally obscured in structures in which the wavefunctions of the electron and trapped hole spatially overlap. This phenomenon has important implications for the oxidation photochemistry of CdS nanocrystals.