Space-Isolated Chromophore for Organic Blue Phosphorescence with High Efficiency and a Deep-Blue Lasing Characteristic

High-efficiency blue phosphorescence and deep-blue laser
emissions
play a crucial role in organic optoelectronic applications. However,
designing metal-free organic blue luminescence with high energy levels
of excited states and suppression of nonradiative transitions remains
a formidable challenge. Herein, we demonstrate a synthetic strategy
for achieving a deep-blue laser and efficient phosphorescence based
on confining chromophores in the tetrahedral structure of sp3 hybridization.
The data analysis reveals that the construction of the quaternary
carbon center contributes to spatially separated donors and acceptors
and considerable steric constraints, prompting an effective intersystem
crossing (ISC) process and suppressing nonradiative transitions. The
negligible interaction between chromophores simultaneously produces
a deep-blue fluorescent laser and blue phosphorescence with an efficiency
up to 82.3%. This work opens the door to multifunctional blue-emitting
materials with high efficiency, providing a high-potential candidate
for electrically pumped organic lasers and energy efficient light-emitting
diodes.