From Kasha to Anti-Kasha: Nanomaterials Unlock Applications

Abstract

Precise controls over light emissions are essential for modern photonic technologies. However, conventional organic luminophores are fundamentally constrained by Kasha’s rule, which restricts emissions to the lowest excited states. Anti-Kasha emissions, where radiative decay occurs directly from higher excited states, break this limitation and opens various spectral possibilities. Recent advances demonstrate that organic nanomaterials provide powerful platforms to stabilize and exploit higher excited-state emissions through structural confinements, symmetry breakings, and vibrational suppressions. These principles enable practical applications across diverse fields, including sensors, optoelectronics, bioimaging, cellular tracking, and photocatalysis. By understanding how molecular-level strategies translate to nanoscale architectures, scientists can utilize higher excited-state emissions for next-generation photonic technologies.