Fig. 2: Phenomena, mechanism, and verification of the LODT.
a Schematic illustration of the experimental procedure for the LODT method. Steps (i)–(iv) visually demonstrate the oxidation of spiro in solution (i) after adding different ATFSI to a spiro/THF solution (ii), followed by light exposure (iii), and final oxidation phenomenon observed through solution color change (iv). b Proposed mechanism for the spiro oxidation assisted by ATFSI. Protons are from the ammonium cations, which accelerate the oxidation reaction under light illumination, then forming oxidized spiro+ in THF solution. c Time-resolved UV-Vis-NIR absorption monitoring of the spiro oxidation process with different ATFSIs under white-light LED illumination. The plot shows the percentage increase rate (ΔA) of absorbance (A) relative to the initial absorbance (At=0) at the peak of 1521 nm. d Electron spin resonance (ESR) spectra of solid spiro samples doped with various ATFSI salts, confirming the formation of radicals. e, f Decay-associated spectra (DAS) for a pristine spiro film and NH4TFSI doped spiro film. The DAS were obtained from transient absorption spectra (TAS) by global fitting with a tri-exponential function.
