Engineering the sign of circularly polarized emission in achiral polymer – chiral small molecule blends as a function of blend ratio

Abstract

Circularly polarized organic light-emitting diodes (CP-OLEDs) that demonstrate both state-of-the-art efficiency and strongly circularly polarized (CP) electroluminescence have proved a considerable technical challenge. Furthermore, multiple factors – from film thickness...

Advances in circularly polarized luminescence materials based on helical polymers

“…They have a g EL of À0.65 and 0.3, respectively. 81,82 These results indicate that F8BT with chiral helical structure has great application potential in CP-OLED. [78][79][80]82 In 2020, Zou et al found that after the irradiation of left-handed or right-handed CPL light, the CPL signal can be measured from achiral luminescent polymer F6BT.…”

“…They have a g EL of −0.65 and 0.3, respectively. 81,82 These results indicate that F8BT with chiral helical structure has great application potential in CP-OLED. 78–80,82…”

Enhancing hole carrier injection via low electrochemical doping on circularly polarized polymer light-emitting diodes

“…10,13 Fuchter, Campbell and coworkers have demonstrated that annealed thin films of blends consisting of a conventional (achiral) electroluminescent polymer and a chiral small molecule additive, 1aza [6]helicene (hereafter, aza [6]H), can exhibit a considerable chiroptical response due to the induction of a chiral phase within the polymer. 9,[14][15][16][17][18] One of the challenges in developing highperformance CP-PLEDs is to identify chiral small molecule additives that (i) have appropriate energy levels to facilitate efficient charge injection and transport and (ii) induce the chiral phase.…”

“…21,22 Such devices still exhibit high V L (410 V) and poor luminance, with |g EL | that is sensitive to the position of the recombination zone. 9,[16][17][18]21,22 Considering the benefits of the EDA in non-CP PLEDs, we questioned whether a combination of three components (i.e., an achiral polymer, a chiral small-molecule additive and the EDA) may present an alternate approach to improve the performance of CP-PLEDs. The key challenge is to maximize the ternary synergetic effect for improved device efficiencies while maintaining the chiral polymer phase that gives rise to high |g EL |.…”

“…21,22 Such devices still exhibit high V L (>10 V) and poor luminance, with | g EL | that is sensitive to the position of the recombination zone. 9,16–18,21,22…”