Beyond Light Harvesting: An Excited-State Perspective on Metal–Organic Framework Photocatalysis

Abstract

Photocatalyst design has traditionally relied on light-harvesting descriptors, including absorption strength, band-gap engineering, and charge-separation efficiency, which primarily characterize excited-state generation rather than utilization. Photocatalytic performance is governed by the kinetic fate of the excited state, where productive electron- and energy-transfer pathways compete with radiative and nonradiative decay. Emissive transition-metal complexes in metal–organic frameworks (MOFs) provide tunable platforms for regulating excited-state dynamics. Through confinement, spatial organization, and local environment control, MOFs suppress nonradiative relaxation, promote charge transfer, and stabilize charge-separated states, enabling excited-state pathways often inaccessible in homogeneous systems. Despite progress, quantitative relationships between photophysical properties and catalytic performance remain poorly understood. This Viewpoint proposes an excited-state-centered framework for photocatalysis using emissive MOF systems to establish quantitative structure–photophysics–reactivity relationships.