Chiral metal-organic frameworks (MOF) composite materials hold great potential for circularly polarized luminescence (CPL) applications, but achieving circularly polarized afterglow remains significant challenging. Herein we present a gel transformation fabrication method to synthesize carbon nanodots (CND) incorporated chiral MOF composite films with circularly polarized afterglow. A chiral amino acid based MOF gel was prepared, combined with pre-synthesized afterglow CND and coated onto an activated quartz substrate. Annealing and drying yielded the CND incorporated chiral MOF composite film (denoted as chirMOF-CND film). Due to the strong chiral transfer and synergistic interaction with gapless connection between the components of chiral MOF film and the afterglow luminophores of CND, the chiral composite film achieves high-performance circularly polarized afterglow. Additionally, the afterglow duration can be modulated by varying the CND concentration. This gel transformation strategy utilizes the unique attributes of chiral MOF and the persistent luminescence of CND for fabricating chiral composite monoliths with seamless integration, advancing next-generation optical devices and sensors applications.

Development of metal-organic framework (MOF) films is of great importance to expand their applications. Herein, we report a facile and universal method of liquid-phase epitaxial (LPE) layer by layer (LBL) brushing approach for fabricating MOF films on various substrates in a high-throughput fashion. This MOF films preparation method offers a great prospective to cost-effectively construct films with short preparation time and little reagent consumption. Moreover, this LBL brushing approach has been implemented successfully to assemble various MOF films, including HKUST-1, zeolitic imidazolate framework-8 (ZIF-8), Cu(bdc), and Cu₂(L)₂P (L = bdc, ndc, and cam; P = dabco and bipy). Afterwards, the classic MOF HKUST-1 and ZIF-8 films were grown on sensor chip electrode and porous fiber support for good volatile organic compounds (VOCs) selective sensing and water purification applications. This study demonstrates that this LBL brushing preparation method can be employed to synthesize various MOF films with a variety of characteristics to realize their sensing and separation applications.

Chiral metal–organic frameworks (chirMOFs) have been widely considered on enantioselective adsorption/separation, asymmetric catalysis, biological and nonlinear optical applications. However, chirMOFs are facing a great challenge in development of chiroptical thin films with circularly polarized luminescence (CPL) property. Here, we first report CPL thin films by encapsulating achiral lanthanide complexes Ln(acac)₃ (Ln = Eu_aTb_bGd_c) into the pores of surface-coordinated chirMOF thin films (SURchirMOF) [Zn₂(cam)₂dabco]_n with layer by layer (lbl) encapsulation strategy. Due to the unique combination of chiral porous MOF and adjustable luminescent complexes in the host–guest thin films, the obtained Ln(acac)₃@SURchirMOF possess strong and tunable CPL property with high dissymmetry factors. The compared CPL and fluorescent lifetime results show that the advantage of this preparation strategy can effectively achieve energy transfer from Ln(acac)₃ to SURchirMOF, resulting in an excellent CPL performance. This study not only provides a novel strategy to develop new types of chiral thin films but also offers an efficient approach for tunable chiroptical applications.