A Dynamic Landscape from Femtoseconds to Minutes for Excess Electrons at Ice−Metal Interfaces

Abstract

Stabilization of excess electrons is studied at crystalline ice-metal interfaces by femtosecond time-resolved two-photon photoelectron spectroscopy and ab initio calculations. Following optical excitation into delocalized image potential states, electrons localize at pre-existing defects which are located at the ice-vacuum interface. Remarkably, the stabilization of these trapped electrons is monitored continuously from femtoseconds up to minutes. By first principle calculations we identify defect structures, that support excess electrons in front of crystalline ice surfaces, and suggest that the stabilization proceeds through subsequent conformational substates. The excess electron wave functions are efficiently screened from the underlying bulk and explain the long residence times observed in the experiment. Thereby, we shed light on the collective character of the nuclear rearrangement that determines the energetics over all timescales.

Kinetics of occupancy of defect states in poly(3-hexylthiophene):fullerene solar cells

“…Shallow traps centered at 50 and 105 meV were previously indentified using thermally-stimulated current techniques on polymer (P3HT) diodes [16]. Activation energies within the range [31], or slow localization dynamics of electrons on ice surfaces [32]. Therefore molecular and lattice distortions in presence of a charge carrier would lie behind the observed retardation effects.…”

Cosmic-ray-driven electron-induced reactions of halogenated molecules adsorbed on ice surfaces: Implications for atmospheric ozone depletion and global climate change

“…They also performed first principle calculations, which lead to a conclusion that the observed long-lived trapped electrons is due to electron trapping at preexisting structural defects on the surface of the crystalline ice [67]. The above-mentioned results have provided a strong foundation for the CR-driven DET reaction mechanism of halogenated molecules adsorbed/trapped at ice surfaces in PSCs.…”

“…In 2000s, Researches on electron solvation dynamics and associated dissociative electron transfer reactions of halogenated molecules have continued in water solution [21,[27][28][29][58][59][60][61][62], ice surface [63], ultrathin ice films [16,17,[64][65][66][67] and H 2 O anionic clusters [68][69][70][71][72][73]. Prior to 2008, many experimental and theoretical studies gave very diverse lifetimes and physical natures of e pre states in liquid water [49][50][51][52][53][54][58][59][60][61][62].…”

“…-11 -workers [17,67], who observed long-lived trapped electrons with a lifetime up to minutes at the crystalline ice surface. They also performed first principle calculations, which lead to a conclusion that the observed long-lived trapped electrons is due to electron trapping at preexisting structural defects on the surface of the crystalline ice [67].…”

Solvation dynamics of surface-trapped electrons at NH3 and D2O crystallites adsorbed on metals: from femtosecond to minute timescales

“…30 These electrons are generated by charge injection from a metal substrate, as opposed to irradiation with low-energy electrons 17 or internal excitation as in refs 18,22. Our approach leads to the formation of E À E vac # 0 eV electrons (i.e.…”