Highly Efficient Blue Crystalline OLEDs Enabled by a Chrysene‐Core Hot Exciton Sensitizer

Combining crystalline materials with emissive materials featuring high exciton utilization efficiency represents an important strategy for developing high‐photon‐output organic light‐emitting diodes (OLEDs). In this work, a novel hot exciton material, PCC, is reported. A non‐doped, amorphous deep‐blue OLED based on PCC exhibits an electroluminescent (EL) emission peak at 436 nm and achieves a maximum external quantum efficiency (EQE) of 13.77%. This is one of the highest performance levels reported for emitters based on the “hot exciton” mechanism. PCC is further embedded as nanoaggregates (NA) into a crystalline host matrix (CHM), serving as a sensitizer for blue dopant (D), enabling efficient exciton utilization. This approach enabled the fabrication of a high‐performance blue crystalline OLED (C‐OLED) with an EQE approaching 10%. Benefiting from the high mobility of CHM, the device exhibited a rapid increase in luminance and current density. Compared with previously reported high‐performance amorphous OLEDs (A‐OLEDs, CIE y ≤ 0.20), the C‐OLED delivered enhanced photon output along with a significantly lower ratio of Joule heat loss due to series resistance. These findings provide new insights into device architecture design for high‐efficiency blue OLEDs.