Mainchain conformation ordering self-assembly tailored room temperature phosphorescence emission

Abstract

Developing organic room-temperature phosphorescence (RTP) materials with a wide range of tunable-emission is significant in expanding the applications of RTP materials. Herein, we rationally designed amphiphilic alternating copolymers poly(1,2-bis(4-alkoxyphenyl)ethane-1,2-dione-alt-(ethylene glycol)_x) (P(Bz-alt-EG_x)) that combined the advantage of alternating benzil and EG_x skeleton, and tunable mainchain conformation. Through a mainchain conformation ordering assembly (COA) process, P (Bz-alt-EG_x) self-assembled into well-defined platelets, and such assemblies emitted blue RTP at ca. 425 nm due to the ordered folded-chain conformation and confined microenvironment. In contrast, traditional self-assembly (TA) of P(Bz-alt-EG_x) obtained less ordered aggregates, such as asymmetric worms, vesicles, and rod-like micelles. The resultant less ordered aggregates exhibited yellow-green RTP at ca. 550 nm. The wide-tuning RTP emission in solution (between blue and yellow-green, over 125 nm) is realized using the P(Bz-alt-EG_x) alternating copolymers under the treatment of different self-assembly conditions. This study uncovers a new strategy to tailor the RTP emission through different self-assembly pathways and holds great promise for the fabrication of advanced optical materials.