Phosphine‐Manipulated p‐π and π‐π Synergy Enables Efficient Ultralong Organic Room‐Temperature Phosphorescence

Abstract

Organic room temperature phosphorescence (RTP) attracts extensive attentions, but still faces the challenge of achieving both high RTP efficiencies (ηRTP) and long lifetimes (τRTP), due to the intrinsic contradiction between triplet radiation and stabilization. In this work, we developed three carbazole‐triphenylphosphine hybrids named xCzTPP, in which phosphine groups provide nonbonding electrons and steric hindrance to modulate intermolecular p‐π and π‐π interactions. With the rational orientations and spatial positions of functional groups, para‐substituted pCzTPP achieves high ηRTP over 10 % and more than twofold increased τRTP (>600 ms), compared to ortho‐ and meta‐ isomers. Theoretical simulation and photophysical investigation indicate that the strongest intermolecular p‐π and π‐π electronic interplays of pCzTPP harmonize high transition probability of 3pπ state and triplet stability of 3ππ state, reflecting the p‐π and π‐π synergy in RTP process.

Double-Model Decay Strategy Integrating Persistent Photogenic Radicaloids with Dynamic Circularly Polarized Doublet Radiance and Triplet Afterglow

“…These results indicate an appropriate ISC process between the hybrid S n state and triplet T n (Figure 5a and Figures S62−S64), which usually generates improved spin−orbit coupling (SOC) values for efficient ISC and an ultralong afterglow lifetime according to EI-Sayed's rule. 69,70 There is only one triplet T 1 below the S 1 states for T 1 /S 1 geometries, indicating the monotonous ISC channels (ξ soc {S 1 − T 1 } = 2.5 cm −1 , Figure 5a and Figure S64), but many plausible ISC channels in the S 0 /crystal geometries increase to 10. These cases also have typical n−π* and π−π* characters (Figures S62 and S63).…”