Katalyse in neuem Licht: Mithilfe hochauflösender Fluoreszenzmikroskopie gelang es erstmals, Transportphänomene und deren Rolle in der Katalyse auf Einzelpartikelebene zu kartieren. Der Thiele‐Modul konnte partikelweise in nur einem einzigen Experiment gemessen werden, und er beweist das Vorliegen von Diffusionsbeschränkungen bei der Ti‐MCM‐41‐katalysierten Epoxidierung eines fluoreszierenden Reportermoleküls (siehe Bild; TBHP=tert‐Butylhydroperoxid).

The influence of heat treatment on the evolution of luminescence in silver exchanged zeolites is investigated under controlled atmosphere by using in situ fluorescence microscopy (see figure). The results indicate that the stable yellow Ag3n+ emitter is most efficiently created in a dry zeolite Y host. In zeolite A, the clusters interact with neighboring clusters or with water, decreasing the overall yellow luminescence.

For polymer solar cells (PSCs), the mixture of polymer donors and small‐molecule acceptors (SMAs) is fine‐tuned to realize a favorable kinetically trapped morphology and thus a commercially viable device efficiency. However, the thermodynamic relaxation of the mixed domains within the blend raises concerns related to the long‐term operational stability of the devices, especially in the record‐holding Y‐series SMAs. Here, a new class of dimeric Y6‐based SMAs tethered with differential flexible spacers is reported to regulate their aggregation and relaxation behavior. In their polymer blends with PM6, it is found that they favor an improved structural order relative to that of Y6 counterpart. Most importantly, the tethered SMAs show large glass transition temperatures to suppress the thermodynamic relaxation in mixed domains. For the high‐performing dimeric blend, an unprecedented open circuit voltage of 0.87 V is realized with a conversion efficiency of 17.85%, while those of regular Y6‐base devices only reach 0.84 V and 16.93%, respectively. Most importantly, the dimer‐based device possesses substantially reduced burn‐in efficiency loss, retaining more than 80% of the initial efficiency after operating at the maximum power point under continuous illumination for 700 h. The tethering approach provides a new direction to develop PSCs with high efficiency and excellent operating stability.

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ZSM‐5 bei der Arbeit: Die säurekatalysierte Kondensation von Furfurylalkohol in den Poren des Zeoliths ZSM‐5 wurde unter dem Fluoreszenzmikroskop verfolgt. Von Reaktionsbeginn bis zur Desaktivierung des Katalysators variiert die Reaktivität der unterschiedlichen Kristallsegmente. Mit der vorgestellten Technik kann diese heterogene Aktivität innerhalb einzelner Kristalle beobachtet werden (siehe Bild).