Enhancing Optoelectronic Properties in Phthalocyanine-Based SURMOFs: Synthesis of ABAB Linkers by Avoiding Statistical Condensation with Tailored Building Blocks

Abstract

Phthalocyanine (PC)-based metal–organic frameworks (MOFs) hold substantial promise for applications in energy storage, sensing, and catalysis due to their robust stability and enhanced electron transfer capabilities. However, synthesizing phthalocyanine linkers with precise geometries presents a significant challenge, which limits their prevalence in the field. Traditional methods typically employ readily synthesized tetratopic PC linkers for realizing PC-based MOFs. In response, the study presents an innovative approach using ditopic ABAB-phthalocyanine MOF linkers. The A and B building blocks in PC synthesis are deliberately designed to circumvent issues of statistical condensation. These PC linkers are then utilized in the fabrication of zinc-based surface-anchored MOF (SURMOF) thin films. The structural and electronic properties of these SURMOFs are explored through a series of detailed experimental and computational methods, including X-ray diffraction, scanning electron microscopy (SEM), and density functional theory (DFT) calculations. UV–Vis spectroscopy reveals significant improvements in electronic absorption, thereby enhancing the material's performance in light harvesting and energy conversion. Furthermore, a photodetector built with this novel linker demonstrates high efficacy in the long-wavelength region (780 nm), highlighting its potential for cutting-edge sensing technologies.