Highly Efficient and Stable Binary‐Doped Narrowband Blue OLEDs Enabled by a Single‐Component Host Matrix with a Spatial Bipolarity Configuration

Highly efficient and stable narrowband blue organic light-emitting diodes (OLEDs) are vital for high-definition displays, yet the achievement of such devices via a concise binary-doped fabrication architecture remains challenging. Herein, an effective and robust single-component host matrix with a spatial bipolarity configuration is developed for high-performance OLEDs. Two elaborately designed molecules are constructed on a non-conjugated silyl linker connecting boron-oxygen and carbazole-derived groups. The boron-oxygen electron-accepting and carbazole-based electron-donating moieties exhibit synergistic and complementary group functions, achieving wide bandgaps of excited energy states, along with thermally activated delayed fluorescence and bipolar carrier transport features. Following the incorporation of a blue multiresonant guest emitter, the doped emissive film showcases enhanced horizontal orientation and photoluminescent efficiency. The binary-doped narrowband blue OLEDs achieve the record maximum external quantum efficiency of 42.3% with low roll-off (efficiency of 38.3% at 1,000 cd m^-2), and the improved operational stability with a half-lifetime of 3076 h at an initial luminance of 100 cd m^-2. This study reveals that the utilization of a spatial bipolarity host matrix is a promising approach to realize narrowband blue OLEDs with concise architecture and high performance.