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Spintronic devices will require long spin lifetimes, but the effect of exciton-lattice coupling on spin lifetime in metal-halide perovskites is not well understood. Here, the authors find a 100-fold increase in the lifetime of exciton spins in a 2D perovskite by exciting with excess energy, resulting from strong coupling between excitons and optically excited phonons.

Ultrafast transient microscopy is a key tool to study the photophysical properties of materials in space and time, but current implementations are limited to ≈1-μm fields of view, offering no statistical information for heterogeneous samples. Recently, we demonstrated wide-field transient imaging based on multiplexed off-axis holography. Here, we perform ultrafast microscopy in parallel around a hundred diffraction-limited excitation spots over a ≈60-μm field of view, which not only automatically samples the photophysical heterogeneity of the sample over a large area but can also be used to obtain a 10-fold increase in signal-to-noise ratio by computing an average spot. We apply our microscope to study the carrier diffusion processes in methylammonium lead bromide perovskites. We observe strong diffusion due to the presence of hot carriers during the first picosecond and slower diffusion afterward. We also describe how many-body kinetics can be misleadingly interpreted as strong diffusion at high excitation densities, while at weak excitation, real diffusion is observed. Therefore, the vast increase in sensitivity offered by this technique benefits the study of carrier transport not only by reducing data acquisition times but also by enabling the measurement of the much smaller signals generated at low carrier densities.

Femtosecond dual-comb lasers have revolutionized linear Fourier-domain spectroscopy by offering a rapid motion-free, precise, and accurate measurement mode with easy registration of the combs beat note in the radio frequency domain. Extensions of this technique already found application for nonlinear time-resolved spectroscopy within the energy limit available from sources operating at the full oscillator repetition rate. Here, we present a technique based on time filtering of femtosecond frequency combs by pulse gating in a laser amplifier. This gives the required boost to the pulse energy and provides the flexibility to engineer pairs of arbitrarily delayed wavelength-tunable pulses for pump–probe techniques. Using a dual-channel millijoule amplifier, we demonstrate programmable generation of both extremely short, fs, and extremely long (>ns) interpulse delays. A predetermined arbitrarily chosen interpulse delay can be directly realized in each successive amplifier shot, eliminating the massive waiting time required to alter the delay setting by means of an optomechanical line or an asynchronous scan of 2 free-running oscillators. We confirm the versatility of this delay generation method by measuring χ(2) cross-correlation and χ(3) multicomponent population recovery kinetics.

Understanding the mechanism of non-radiative losses in organic photovoltaics is crucial to improve the performance further. Here, the authors use combined device and spectroscopic data to reveal universal model to maximise exciton splitting and charge separation by adjusting the energy of charge transfer state.

Andrea Romigi,1 Giuseppe Vitrani,1 Temistocle Lo Giudice,1 Diego Centonze,1,2 Valentina Franco3 1IRCCS Istituto Neurologico Mediterraneo Neuromed, Pozzilli (IS), Italy; 2Department of System Medicine, University of Rome Tor Vergata Rome, Italy; 3IRCCS Mondino Foundation, Pavia, Italy Abstract: Narcolepsy is a rare sleep disorder characterized by excessive daytime sleepiness and rapid eye movement sleep dysregulation, manifesting as cataplexy and sleep paralysis, as well as hypnagogic and hypnopompic hallucinations. Disease onset may occur at any age, although adolescents and young adults are mainly affected. Currently, the diagnosis delay ranges from 8 to 10 years and drug therapy may only attenuate symptoms. Pitolisant is a first-in-class new drug currently authorized by the European Medicines Agency to treat narcolepsy with or without cataplexy in adults and with an expanded evaluation for the treatment of neurologic diseases such as Parkinson’s disease and epilepsy. This article reviews the pharmacokinetic and pharmacodynamic profile of pitolisant, highlighting its effectiveness and safety in patients with narcolepsy. We performed a systematic review of the literature using PubMed, Embase, and Google Scholar. We report on the efficacy and safety data of pitolisant in narcoleptic patients regarding cataplexy episodes and subjective and objective daytime sleepiness. The development program of pitolisant was characterized by eight Phase II/III studies. One proof-of-concept study followed by two pivotal studies, three randomized controlled trials, and two open studies were evaluated. Our review confirmed the effectiveness of pitolisant in treating major clinically relevant narcolepsy symptoms, including cataplexy, as compared to placebo. In addition, pitolisant revealed a safe profile when compared with placebo and active comparators. Headache, insomnia, and nausea were the prominent side effects. Further long-term randomized controlled trials comparing the efficacy of pitolisant with active comparators (ie, modafinil and sodium oxybate) may clarify its real place in therapy and its possible use as a first-line agent on the basis of its safety and tolerability. Keywords: pitolisant, narcolepsy, cataplexy, histamine, excessive daytime sleepiness

Andrea Romigi,1,2 Eti A Femia,3 Cinzia Fattore,4 Giuseppe Vitrani,1 Giancarlo Di Gennaro,1 Valentina Franco4 1Istituto Neurologico Mediterraneo, IRCCS Neuromed, Pozzilli (IS), Italy; 2Neurophysiopathology Department, University of Rome Tor Vergata, Rome, Italy; 3Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milano, Italy; 4Clinical Trial Centre & Antiepileptic Drugs, C. Mondino National Neurological Institute, Pavia, Italy Abstract: Zonisamide (ZNS), a second-generation antiepileptic drug, indicated as add-on treatment of focal epilepsy, has been recently approved as monotherapy for the treatment of partial seizures in adults affected by newly diagnosed epilepsy in Europe. Evidence on the efficacy and tolerability of antiepileptic drugs in the elderly is still lacking as these patients are frequently excluded from clinical trials. Here, a comprehensive overview of available data regarding the use of ZNS in the treatment of epilepsy in elderly people is provided. In a pooled analysis conducted in patients aged ≥65 years, no new/unexpected safety findings have emerged. Few data from uncontrolled investigations suggest that ZNS may be effective and well tolerated when administered as monotherapy or adjunctive antiepileptic treatment in the elderly. However, evidence from these observational studies is less than satisfactory, and randomized controlled trials focused on these patients are still needed. Keywords: zonisamide, elderly, epilepsy, safety, efficacy

We unravel the electronic structure of graphene nanoribbons in solution using two-dimensional electronic spectroscopy. We identify different excitons, their vibrational couplings and find that exciton diffusion or relaxation among the exiton sublevels takes place in ~300 fs.

We use 2D electronic spectroscopy with sub-10-fs resolution to probe carrier-carrier scattering in perovskites. We report excitation-density dependent thermalization times below 100-fs. Strong coupling with excitonic states further reveals sub-bandgap states with low oscillator strength.

Using broadband transient absorption in a high efficiency (>11%) photovoltaic blend with a non-fullerene acceptor, we observe instantaneous (sub-30 fs) charge separation, demonstrating close to ideal donor-acceptor level matching and nanomorphology in this blend.

In this work, the timescales and mechanisms associated with the structural dynamics of butadiyne-linked porphyrin dimers are investigated through time resolved narrowband pump/broadband probe transient absorption spectroscopy. Our results confirm previous findings that the broadening is partly due to a distribution of structures with different (dihedral) angular conformations. Comparison of measurements with excitations on the red and blue sides of the Q-band unravel the ground and excited state conformational re-equilibration timescales. Further comparison to a planarized dimer, through the addition of a ligand, provides conclusive evidence for the twisting motion performed by the porphyrin dimer in solution.

The prologue of the Lysis is integral to the issues addressed in the dialogue, as it illustrates an ordinary concern, friendship, which in fact gives rise to extraordinary philosophical analysis and continues as central to the analysis.

Hot water savings from water-efficient lavatory fittings lead to reductions in water heating energy consumption, and ultimately to decreases in carbon emissions. This paper characterizes existing and proposed approaches used to estimate hot water savings and carbon emissions reductions stemming from the U.S. Environmental Protection Agency's WaterSense program. Also described are refinements that improve the accuracy of residential hot water use percentage estimates of lavatory fittings. The authors conclude that (1) hot water percentages for showers and faucets calculated using up-to-date, publicly available national data are consistent with those found by regional studies and household-level models of water use; (2) the accuracy of heating energy savings estimates attributable to WaterSense-labeled lavatory products, as well as associated emissions reductions, can be refined by modifying the existing energy factor/uniform energy factor (EF/UEF)-based estimation approach with available data. The refined approach accounts for more nuanced conditions than the EF/UED-based approach but depends on data not always available; and (3) the approaches described and intermediate outputs can be generalized for other water conservation programs or estimating purposes.