Post-synthetic gridization enhances spin-flip dynamics, horizontal alignment, and ozone resistance in solution-processable TADF macrocycles

Abstract

Nanoemitters play a pivotal role in advancing OLED technologies toward flexible, efficient, and sustainable display platforms. However, current quantum dots and perovskite LEDs suffer from structural instability and environmental sensitivity, limiting their scalability. Here, we introduce a post-synthetic gridization strategy to construct robust, solution-processable organic nanodots. The resulting A-shaped nanogrid (AG) framework provides a rigid and sterically protected donor scaffold that suppresses aggregation-caused quenching, promotes horizontal dipole orientation and ozone resistance, and minimizes reorganization energy. Based on this design, the thermally activated delayed fluorescence (TADF) emitter AG-PXZ-TRZ exhibits a 3.1-fold enhancement in the radiative decay rate and a 5.5-fold acceleration of reverse intersystem crossing relative to the parent emitter PXZ-TRZ, together with an improved horizontal molecular orientation of 83%. Solution-processed OLEDs based on AG-PXZ-TRZ achieve an external quantum efficiency of 28.9%, markedly surpassing the performance of both PXZ-TRZ and the arylmethylated analogue DPFPXZ-TRZ. This work establishes molecular gridization as an effective pathway toward stable and high-performance organic nanoemitters for next-generation optoelectronic displays.