Circularly polarized luminescent (CPL) materials have attracted many attentions due to their potential applications in 3D imaging, anti-counterfeiting, etc. However, it is still a great challenge to achieve circularly polarized...

Circularly polarized luminescent materials show significant application in display devices, optical instruments, bionic fields, etc. In this work, we design and prepare a chiral luminescent liquid crystalline polymer, namely, poly(4,4',4″-tricholesterylformate-oxytetraphenylethylene-methyl acrylic acid ester) (P1). Polarizing optical microscopy (POM) and X-ray diffraction (XRD) results indicate that this polymer forms a hexagonal columnar phase. Circularly polarized luminescence (CPL) experiment shows that no CPL signal is observed for the polymer in the bulk, but the polymer mixed with a small amount of 4-cyano-4′-pentylbiphenyl (5CB) (P1@5CB) presents a strong CPL signal with a luminescence asymmetry factor (g lum) of +0.18. Further, Förster resonance energy transfer (FRET) is adopted to regulate the CPL using P1 as energy/chiral donors and the achiral long-wavelength Nile red (NR) dyes as acceptors. The resultant compound shows a bathochromically shifted emission by up to 160 nm compared with P1@5CB and also emits an efficient CPL with a g lum of +0.20. This result demonstrates that the controllable regulation of efficient CPL with an efficient glum is realized through nonradiative resonance energy transfer and chiral transfer.

Polyimide (PI), an important engineering polymer with a rigid chemical structure, readily has excellent chemical stability, heat resistance, and electrical insulation but lacks broadband photothermal properties. Herein, we design and synthesize PI copolymers that embrace intrinsic photothermal properties by using two diamine monomers of (Z)‐2,3‐bis(4‐aminophenyl) acrylonitrile (CNDA) and 4,4‐diphenyldiamine (NDA) with strong ultraviolet (UV), and near‐infrared (NIR) absorption capabilities, respectively. Tuning the molar ratio of the two diamines can modulate UV and NIR light absorption and regulate the intrinsic photothermal properties of PIs. After condensation with pyromellitic dianhydride, the resulting PI‐0.5 with a unit molar ratio of CNDA:NDA = 1 shows the best photothermal efficiency. PI‐0.5 is used to construct 3D steam generators with vertically dried channels by a freeze‐drying method. The 3D steam generators show a good water evaporation rate and continuously operate with excellent stability under varying salinity and pH conditions. The synthetic design herein suggests that PI can be molecularly engineered to be intrinsic photothermal materials, expanding the properties and applications of existing PIs.

Circularly polarized luminescence (CPL) has been widely demonstrated that the circular polarization in excited state can be significantly amplified through the triplet-triplet annihilation-based upconversion (TTA-UC) luminescence process in various chiral nano-assemblies. However, constructing such an upconverted circularly polarized luminescence (UC-CPL) system in the aqueous phase remains a challenge. In this work, a kind of amphiphilic chiral cationic gemini surfactant is utilized to construct chiral spherical micelle in the aqueous phase, whose internal chiral cavity can provide a hydrophobic and deoxygenated environment for air-sensitive TTA-UC system. In addition, due to the co-assembly process between the emitters and chiral micelles, achiral emitters of upconversion pairs exhibit induced chiroptical properties. More importantly, the luminescence dissymmetry factor ( g lum ) can be amplified by one order of magnitude through TTA-UC process. This work provides an effective and useful strategy for realizing UC-CPL in aqueous phase.