Revealing Ultrafast Energy Dissipation Pathway of Nanocrystalline Sunscreens Oxybenzone and Dioxybenzone

Abstract

Two widely used ultraviolet filters, oxybenzone and dioxybenzone, are applied in a variety of areas, particularly in sunscreen cosmetics. Ultrafast femtosecond transient absorption is utilized to trace the excited states and transient states of the nanocrystalline suspension and solution phase of these two molecules. The analysis reveals the intriguing discovery that the transient species of the oxybenzone nanocrystalline suspension have shorter lifetimes than that in solution. The energy dissipation mechanism of these molecules is simulated by density functional theory calculations, and the potential energy surface calculations and the single-crystal structure can well explain the fast decay dynamics of the nanocrystalline transient states of these two molecules.

Disentangling Multiple Effects on Excited‐State Intramolecular Charge Transfer among Asymmetrical Tripartite PPI‐TPA/PCz Triads

“…Fs-TAs pectroscopy can detect and trace the excited states and transients pecies after excitation of the molecules on as pecific timescale. [42,43] Performing the studies on PPI-TPA/PCz triads in as trongly polar organic solvent such as DMF and an onpolar organic solventd ichloromethane may aid in probing the influence of solventp olarity on the dipole moment of excited states and the rate of charge separation (CS). [44,45] Fs-TAe xperiments were performed to monitort he excited-states evolution of triad 1 in DMF solution under excitation at 330 nm ( Figure 2).…”

“…The fs-TAm easurements were performed with apparatus and methods detailed previously. [42,43] In brief, fs-TAs pectra were obtained by employing the harmonic (330 and 360 nm light) for the pump pulse and white-light continuum (350-800 nm light) for the probe pulse generated from the 800 nm output of af emtosecond regenerative amplified Ti :sapphire laser system For the measurements herein, 40 mL of solution was passed through a2mm-thick cell, excited by 330 and 360 nm pump pulse, and then interrogated by the white light continuum pulse.…”

Precise Ligand Tuning Emission of Mn-Doped CsPbCl3 Nanocrystals by the Amount of Sulfonates

“…Unprecedentedly, a series of sulfonate ligands are introduced to successfully tune the dual-color emission of the Mn:CsPbCl 3 NCs. Furthermore, ultrafast femtosecond transient absorption (fs-TA) spectroscopic studies 57,58 To synthesize the Mn:CsPbCl 3 NCs, a two-precursor supersaturated recrystallization route is used at room temperature (Figure S1). This method is low-cost and simple when compared with the high-temperature hot injection and postsynthesis method.…”

“…Unprecedentedly, a series of sulfonate ligands are introduced to successfully tune the dual-color emission of the Mn:CsPbCl 3 NCs. Furthermore, ultrafast femtosecond transient absorption (fs-TA) spectroscopic studies , have been carried out to reveal the ligand tuning mechanism. Finally, the Mn:CsPbCl 3 NCs treated with sulfonate ligands as photoluminescence (PL) probe are employed to detect the Cu 2+ with good sensitivity and selectivity.…”

Photoprotective Properties of Eumelanin: Computational Insights into the Photophysics of a Catechol:Quinone Heterodimer Model System

“…In oxybenzone, for example, π*←π excitation of the dominant (in the ground (S 0 ) state) enol-conformer populates the strongly absorbing 1 ππ* state, which relaxes-either directly or via an (optically dark) 1 nπ* state-toward its minimum energy keto-configuration (i.e., an intramolecular H atom transfer (HAT) process) and onwards towards the CI with the S 0 state at non-planar geometries (one ring twists relative to the other about the central aliphatic C-C bond). A reverse H atom transfer process on the S 0 PES and vibrational energy transfer to the surrounding solvent results in (efficient, but not complete) reformation of the original enol-conformer with a (solvent-dependent) time constant [32,[68][69][70][71][72].…”