The precision of array of laser applications and manipulation on smaller scales are limited by the so-called 200 nm wall, and breakthroughs rely on the discovery of new materials with transparency and phase matchability in the ultraviolet and deep ultraviolet region. Herein, we discover an unprecedented alignment of the asymmetric non-π-conjugated species [PO3F] in NaNH4PO3F·H2O, which allows the best uniform P–F bond orientation that generates a remarkable enhancement of the (010) in-plane anisotropy that yields the largest birefringence (obv.: 0.053) to date in the phosphate and fluorophosphate families. The substance produces second harmonic generation lasers through direct frequency doubling with incident Yb:KGW femtosecond lasers on an as-synthesized (010) wafer with a size of 14 × 10 × 2.1 mm3. According to the calculated refractive index dispersion curve, the shortest second-harmonic generation (SHG) wavelength is estimated to be 194 nm, the shortest among phosphates and monofluorophosphate. These insights may help to design other high-performance non-π-conjugated deep-UV nonlinear optical materials.

Chloride ion–pumping rhodopsin (ClR) in some marine bacteria utilizes light energy to actively transport Cl− into cells. How the ClR initiates the transport is elusive. Here, we show the dynamics of ion transport observed with time-resolved serial femtosecond (fs) crystallography using the Linac Coherent Light Source. X-ray pulses captured structural changes in ClR upon flash illumination with a 550 nm fs-pumping laser. High-resolution structures for five time points (dark to 100 ps after flashing) reveal complex and coordinated dynamics comprising retinal isomerization, water molecule rearrangement, and conformational changes of various residues. Combining data from time-resolved spectroscopy experiments and molecular dynamics simulations, this study reveals that the chloride ion close to the Schiff base undergoes a dissociation–diffusion process upon light-triggered retinal isomerization.

No abstract

Electron-doped Sr2IrO4 is the best candidate for unconventional superconductivity, but direct evidence of superconductivity has not been experimentally confirmed. Therefore, it is urgent to explore the complex and rich physical properties caused by doping. The planar Hall effect (PHE) is a sensitive technique for the characterization of intrinsic magnetic properties in magnetic thin films and is applied widely in spintronic devices. In this work, the PHE for La-doped Sr2IrO4 films as a function of the magnetic field direction and temperature exhibited unique properties caused by electron doping. The amplitude of PHE is proportional to the strength of the applied magnetic field. Remarkably, as the temperature increased, a sign reversal of angle-dependent PHE occurred at 90 K, which indicated the change of magnetic anisotropy. Subsequent variable-temperature traditional Hall measurements and time-resolved optical studies eliminated different types of carrier interactions. The anisotropic magnetoresistance measurements indicated that the sign reversal can be attributed to the changes of a spin structure after electron doping, and the reversal temperature is related to the strength of ferromagnetism. These results provide a platform to study the magnetic interactions and suggest the possibility of realizing thermal controllable magnetic sensor devices in electron-doped Sr2IrO4 films.

The research on perylene diimide (PDI) aggregates effectively promotes their applications in organic photovoltaic solar cells and fluorescent sensors. In this paper, a PDI fabricated with three peripheral PDI units (N, N’-bis(6-undecyl) perylene-3,4,9,10-bis(dicarboximide)) is investigated. The trimer shows different absorption and fluorescence properties due to hydrophobicity when dissolved in the mixed solvent of tetrahydrofuran (THF) and water. Through comprehensive analysis of the fluorescence lifetime and transient absorption spectroscopic results, we concluded that the trimer underwent different excited state kinetic pathways with different concentrations of water in THF. When dissolved in pure THF solvent, both the intramolecular charge-transfer and excimer states are formed. When the water concentration increases from 0 to 50% (v/v), the formation time of the excimer state and its structural relaxation time are prolonged, illustrating the arising of the intermolecular excimer state. It is interesting to determine that the probability of the intramolecular charge-transfer pathway will first decrease and then increase as the speed of intermolecular excimer formation slows down. The two inflection points appear when the water concentration is above 10% and 40%. The results not only highlight the importance of hydrophobicity on the aggregate properties of PDI multimers but also guide the further design of PDI-based organic photovoltaic solar cells.