Two-Photon Excited Fluorescence of Tetraphenylethylene-Based Metal–Organic Frameworks under Pressure with Different Ligand Arm Lengths

Abstract Metal–organic frameworks (MOFs) with excellent two-photon excited fluorescence (TPEF) properties have shown great potential in multiple fields. While numerous pressure-responsive TPEF MOFs have been reported, the precise modulation of their optical performance via structural design remains a critical challenge. In this study, the impact of ligand coordination arm length on the TPEF properties of tetraphenylethylene-based MOFs (TPE-MOFs) was systematically explored. By designing two TPE-MOFs with varying coordination arm lengths, it was demonstrated that LIFM-DJZ-1, based on L1 with long coordination arms, exhibited superior PLQY and TPA action cross sections compared to LIFM-DJZ-2 with shortened L2. Notably, pressure stimulation further enhanced the TPEF performance of LIFM-DJZ-1, highlighting the potential of structural modulation in designing high-performance piezofluorochromic materials. This study not only offers fresh insights into the structure-property relationship in TPE-MOFs but also establishes a crucial foundation and practical guideline for advancing the development of high-performance TPE-MOF materials.