Dual-Mode Induction of Tunable Circularly Polarized Luminescence from Chiral Metal-Organic Frameworks

Abstract

<jats:p>The general approach for fabricating solid-state materials showing circularly polarized luminescence (CPL) is still in its challenge. In this work, chiral metal-organic frameworks (MOFs) with full-color and white-color circularly polarized light emission are firstly achieved through a host-guest emitter-loading strategy. Chiral zeolitic imidazolate frameworks (ZIFs, a class of MOFs) are fabricated by a facile and simple mixed-ligand coassembly pathway. Meantime, achiral dyes, quantum dots (QDs), and upconversion nanoparticles (UCNPs) are easily loaded into the chiral ZIFs during the synthetic process. Size-matched dyes can be solely encapsulated into the chiral cages of ZIF, resulting in induced CPL and enhanced luminescence efficiency in solid-state <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mtext>ZIF</mml:mtext><mml:mo>⊃</mml:mo><mml:mtext>dye</mml:mtext></mml:math> composites. Large-sized QDs, after embedding into the gap of the ZIF particles, also exhibited intense CPL activity. Furthermore, through modulating the blending ratio of colored dyes or QDs in chiral ZIFs, white light-emitting ZIFs with circular polarization could be constructed in a solid state. In addition, through loading rare earth element-based upconversion nanoparticles (UCNPs) into chiral ZIFs, upconverted CPL (UC-CPL) could be achieved with a high dissymmetry factor (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:msub><mml:mrow><mml:mi>g</mml:mi></mml:mrow><mml:mrow><mml:mtext>lum</mml:mtext></mml:mrow></mml:msub></mml:math>). Thus, various achiral luminophores were endowed with CPL upon coupling with chiral ZIFs, which significantly deepened and enlarged the research scope of the chiroptical materials in a solid state.</jats:p>

Boosting Circularly Polarized Luminescence of Organic Conjugated Systems via Twisted Intramolecular Charge Transfer

“…In recent years, organic π-conjugated functional materials [1][2][3], especially chiroptical materials featuring with circularly polarized luminescence (CPL), have attracted growing interest for their wide potential applications in threedimensional (3D) optical displays [4], optical storage and processing systems [5], color-image projection [6], liquid crystal lasers [7], biological probes and signatures [8], security tags [9], light-emitting diodes [10][11][12], and, especially, backlighting liquid crystal displays [13]. Concerning CPLactive materials, one of the major targets is to achieve a large luminescence dissymmetry factor (g lum ), which reflects the level of CPL properties.…”

Chiral Reticular Self‐Assembly of Achiral AIEgen into Optically Pure Metal–Organic Frameworks (MOFs) with Dual Mechano‐Switchable Circularly Polarized Luminescence

“…Reticular chemistry offers a rich opportunity to integrate different organic units to produce stable functional materials. If chiral units and luminophores were connected through a chiral reticular self‐assembly, it was expected that the chiral framework would enable a different manner of chirality transfer for CPL materials . In addition, the chiral framework could experience either global or local dynamics under external stimuli to fabricate responsive functional materials .…”

Recent Advances of Circularly Polarized Luminescence in Photon Upconversion Systems

“…Interestingly, UC-CPL can also be achieved by introducing UCNPs-Er into chiral metal-organic frameworks (MOFs) matrixes (Figure 6b). 51 Excited by a 980 nm laser, MOFs/UCNPs composites showed UC-CPL emission wavelength from 390 nm to 700 nm with g lum around 10 ¹2 .…”