Recent Progress on Circularly Polarized Luminescence of Chiral Organic Small Molecules

Molecular Design, Circularly Polarized Luminescence, and Helical Self‐Assembly of Chiral Aggregation‐Induced Emission Molecules

“…CPL activity is generally evaluated by the emission dissymmetry factor ( g em ), which is defined as g em =2( I L − I R )/( I L + I R ), where I L and I R are the emission intensities of the left‐ and right‐handed circularly polarized light, respectively. Up to now, most of the reported CPL materials based on the conventional luminophors have been investigated in dilute solutions, and show absolute g em values in the range 10 −5 –10 −2 . Their CPL performance, however, usually becomes worse in the condensed phase owing to the ACQ effect.…”

“…[53][54][55][56] CPL activity is generally evaluated by the emission dissymmetry factor (g em ), which is defined as g em = 2(I L ÀI R )/(I L + I R ), where I L and I R are the emission intensities of the left-and right-handed circularly polarized light, respectively.U pt on ow, most of the reported CPL materials based on the conventional luminophors have been investigated in dilute solutions, and show absolute g em values in the range 10 À5 -10 À2 . [54][55][56][57] Their CPL performance, however,u sually becomes worse in the condensed phase owing to the ACQ effect.C onsidering that CPL materials are inevitably employed in the film or solid state for practical use, development of new chiral fluorophors with both high g em values and emission efficiency in the solid state is thus highly demanded. The unique luminescence properties of the AIEgens make them ideal candidates to constructe fficient CPL-active materials.…”

Thermally activated delayed fluorescence material-sensitized helicene enantiomer-based OLEDs: a new strategy for improving the efficiency of circularly polarized electroluminescence

“…Especially, CP-OLEDs based on chiral fluorescent emitters could not only successfully achieve the CPEL [17][18][19], but also have the advantages of long device lifetime, good stability and low efficiency roll-off. Moreover, chiral fluorescent molecules with CPL activities are also cheap and easily available [20][21][22][23]. However, the devices based on fluorescent emitters generally suffer low efficiencies for only 25% exciton utilization of the fluorophores (Fig.…”

Chiral Diketopyrrolopyrrole-Helicene Polymer With Efficient Red Circularly Polarized Luminescence

“…Circularly polarized (CP) light has received renewed attention owing to its superior potential over unpolarized one in a diverse range of domains such as (chir)optoelectronics (stereoscopic displays, organic light-emitting diodes (OLEDs), optical information processing, etc.) as well as in bio-imaging and chiral sensing (Riehl and Richardson, 1986;Berova et al, 2000Berova et al, , 2012Carr et al, 2012;Maeda and Bando, 2013;de Bettencourt-Dias, 2014;Kumar et al, 2015a;Di Bari, 2015, 2018;Zinna et al, , 2017Brandt et al, 2016;Longhi et al, 2016;Li et al, 2017;Han et al, 2018;Tanaka et al, 2018). Until recently, luminescent chiral lanthanides complexes have been the most studied molecular CPL emitters since this family of compounds can display relatively high level of circularly polarized emission, characterized by a luminescence dissymmetry factor g lum = 2(I L -I R )/(I L +I R ), of more than 1 (Carr et al, 2012;Zinna and Di Bari, 2018).…”

“…However, lanthanide complexes often possess low luminescent quantum yield (φ) and stability issues, which may difficultly render their integration in optoelectronic devices such as CP-OLEDs, chiral photovoltaics and transistors for example. To circumvent these aspects, the development of chiral emitting small organic molecules (SOM) has gained increasing interest, also benefiting from their tunable photophysical and chiroptical properties from the blue to the near-infrared spectral region (Li et al, 2017;Han et al, 2018). One particularly appealing synthetic strategy to design efficient CPL emitters has consisted in developing chirally perturbed π-extended achiral chromophores, mostly based on C 2 -symmetric chiral moieties (chiral binaphthyl or 1,2-diamino-cyclohexane derivatives) linked to bodipy or perylene organic dyes (Tsumatori et al, 2010;Langhals et al, 2011;Kumar et al, 2013Kumar et al, , 2014Kumar et al, , 2015bSánchez-Carnerero et al, 2014;Sheng et al, 2016).…”