Continuous Tuning of Intersystem Crossing Times in Rose Bengal Water/Methanol Solutions.

We use femtosecond transient broadband absorption spectroscopy (TAS) to characterize Rose Bengal in water/methanol solutions and reveal a continuous tunability of intersystem crossing (ISC) times by changing the mole fraction of the solvents. We find that the transients of excited state absorptions (ESAs) in Rose Bengal at ∼430 nm can be attributed to transitions from the singlet state S, with decay times of 74 ps via ISC in pure water and up to 405 ps in pure methanol. TA measurements at near-infrared wavelengths, on the other hand, reveal the rise of an ESA at ∼1080 nm from the triplet state T with time constants of 68 and 491 ps in pure water and methanol, respectively, strongly supporting the associated UV-vis TAS data.

Fluorescence lifetime imaging unravels the pathway of glioma cell death upon hypericin-induced photodynamic therapy.

Malignant primary brain tumors are a group of highly aggressive and often infiltrating tumors that lack adequate therapeutic treatments to achieve long time survival. Complete tumor removal is one precondition to reach this goal. A promising approach to optimize resection margins and eliminate remaining infiltrative so-called guerilla cells is photodynamic therapy (PDT) using organic photosensitizers that can pass the disrupted blood-brain-barrier and selectively accumulate in tumor tissue.

A Saddle-Shaped Expanded Porphyrinoid Fitting C.

We present the synthesis of a new type of an expanded porphyrinoid macrocycle with a saddle-shaped morphology and its complexation of C guest molecules. The new macrocycle contains four carbazole and four triazole moieties and can be readily synthesized via a copper-catalyzed click reaction. It shows specific photo-physical properties including fluorescence with a high quantum yield of 60 %.

Zwitterionic Carbazole Ligands Enhance the Stability and Performance of Perovskite Nanocrystals in Light-Emitting Diodes.

We introduce a new carbazole-based zwitterionic ligand (DCzGPC) synthesized via Yamaguchi esterification which enhances the efficiency of lead halide perovskite (LHP) nanocrystals (NCs) in light-emitting diodes (LED). A facile ligand exchange of the native ligand shell, monitored by nuclear magnetic resonance (NMR), ultraviolet-visible (UV-vis), and photoluminescence (PL) spectroscopy, enables more stable and efficient LHP NCs. The improved stability is demonstrated in solution and solid-state LEDs, where the NCs exhibit prolonged luminescence lifetimes and improved luminance, respectively.

Preparation, photoluminescence and excited state properties of the homoleptic cluster cation [(WI)(CHCN)].

Solvated tungsten iodide cluster compounds are presented with the homoleptic cluster cation [(WI)(CHCN)] and the heteroleptic [(WI)I(CHCN)], synthesized from WI in acetonitrile. Crystal structures were solved and refined on deep red single-crystals of [(WI)(CHCN)](I)(BF)·HO, [(WI)I(CHCN)](I)(BF), and on a yellow single-crystal of [WI(CHCN)](BF)·2(CHCN) on the basis of X-ray diffraction data. The structure of the homoleptic [(WI)(CHCN)] cluster is based on the octahedral [WI] tungsten iodide cluster core, coordinated by six apical acetonitrile ligands.