Nan Li, Yunsheng Wang, Siyuan Chen, Jin Li, Zhen Li
Electrical treeing, manifesting as Lichtenberg figures (LFs) is a major cause of dielectric failure in power, communication, and aerospace systems. Visualization of LF evolution has been hindered by passive imaging limits. Here, we introduce phosphorescence imaging of Lichtenberg figures (PI-LF), which maps both structural damage and localized oxygen depletion via high-contrast luminescent signals. Guided by a mechanistic understanding of oxygen metabolism in photoactivated phosphorescent systems, indole-core dopants with tunable chromaticity reveal dual oxygen pathways: energy transfer to singlet oxygen and electron transfer to superoxide radicals. Polymer systems doped with these luminophores resolve fine structural progression of electrical trees, enabling bioimaging-style analysis that uncovers a previously hidden spherical-layered growth mode. PI-LF bridges molecular photophysics and high-voltage engineering, establishing a paradigm for luminescence-based visualization of dielectric breakdown.