Common ground and divergence: OLED emitters as photocatalysts.

Many photocatalysts were initially developed or used as emitters for organic light emitting diodes (OLEDs). This feature article summarizes the different generations of OLED emitters and connects the photophysical processes with those relevant for photocatalysis. The focus is on the general properties OLED emitters and photocatalysts are designed for and how photocatalysis has benefitted from OLED research. Sometimes optimization of an OLED emitter leads to a better photocatalyst while some properties are optimized into opposite directions. To discover new classes of photocatalysts in the future it is important to consider what good OLED emitters and good photocatalyst have in common and where they diverge. Within recent years, fully organic thermally activated delayed fluorescence (TADF) emitters had the most significant impact in both fields and thus are discussed with specific focus.