Rational Design of Multicolor‐Emitting Chiral Carbonized Polymer Dots for Full‐Color and White Circularly Polarized Luminescence

Abstract

Light‐emitting chiral carbonized polymer dots (Ch‐CPDs) are attracting great interest because of their extraordinary photonic properties, but modulating their band‐gap emission, especially at long wavelength, and maintaining their chiral structure to achieve multicolor, high‐emission Ch‐CPDs remains challenging. Reported here for the first time is the synthesis of red‐ and multicolor‐emitting Ch‐CPDs using the common precursors L‐/D‐tryptophan and o‐phenylenediamine, and a solvothermal approach at one temperature. The quantum yield of the Ch‐CPDs was between 31 % and 54 %. Supramolecular self‐assembly provided multicolor‐emitting Ch‐CPDs showing novel circularly polarized luminescence, with the highest dissymmetric factor (glum) of 1×10−2. Importantly, circularly polarized white‐emitting CPDs were fabricated for the first time by tuning the mixing ratio of the three colored Ch‐CPDs in a gel. This strategy affords exciting opportunities for designing functional chiroptical materials.

Narrow‐bandwidth emissive carbon dots: A rising star in the fluorescent material family

“…Recently, Lu et al prepared multicolor emissive CDs through a solvothermal treatment of tryptophan and o-phenylenediamine. 130 By simply changing the reaction solvent while keeping the other reaction conditions unchanged, blue-, yellow-, and redemitting CDs were obtained, with maximum PLQY of 53.6%, 31.6%, and 46.4%, respectively. Interestingly, the re-emitting CDs showed an extremely narrow FWHM of about 23 nm, while broad FWHMs were observed in the other two CDs (Figure 8C).…”

“…In that process, formamide not only served as reaction media but also promoted the formation of CDs. Recently, Lu et al prepared multi‐color emissive CDs through a solvothermal treatment of tryptophan and o ‐phenylenediamine 130 . By simply changing the reaction solvent while keeping the other reaction conditions unchanged, blue‐, yellow‐, and red‐emitting CDs were obtained, with maximum PLQY of 53.6%, 31.6%, and 46.4%, respectively.…”

“…(C) Fluorescence spectra of the CDs prepared from tryptophan and o ‐phenylenediamine. Reproduced with permission: Copyright 2021, Wiley 130 . CD, carbon dot…”

“…Reproduced with permission: Copyright 2021, Wiley. 130 CD, carbon dot heating of glutathione in formamide, Lin and coworkers prepared near-infrared emissive CDs with a narrow emission band of 30 nm. 120 In that process, formamide not only served as reaction media but also promoted the formation of CDs.…”

Chiral carbon dots: synthesis, optical properties, and emerging applications

“…As the field of chiral carbon dots gained more traction, more systematic studies on the origin and mechanism of chirality surfaced 56 – 58 . Recent years have brought potential applications of chiral carbon dots into the spotlight, such as multi-color-emission 59 , chiral catalysis 60 , and bio-applications such as DNA rearrangement 61 . This was complemented by interesting optical phenomena of these materials, such as two-photon absorption 62 and circularly polarized light emission 63 , 64 .…”