Marcus inverted region of charge transfer from low-dimensional semiconductor materials

Abstract

A key process underlying the application of low-dimensional, quantum-confined semiconductors in energy conversion is charge transfer from these materials, which, however, has not been fully understood yet. Extensive studies of charge transfer from colloidal quantum dots reported rates increasing monotonically with driving forces, never displaying an inverted region predicted by the Marcus theory. The inverted region is likely bypassed by an Auger-like process whereby the excessive driving force is used to excite another Coulomb-coupled charge. Herein, instead of measuring charge transfer from excitonic states (coupled electron-hole pairs), we build a unique model system using zero-dimensional quantum dots or two-dimensional nanoplatelets and surface-adsorbed molecules that allows for measuring charge transfer from transiently-populated, single-charge states. The Marcus inverted region is clearly revealed in these systems. Thus, charge transfer from excitonic and single-charge states follows the Auger-assisted and conventional Marcus charge transfer models, respectively. This knowledge should enable rational design of energetics for efficient charge extraction from low-dimensional semiconductor materials as well as suppression of the associated energy-wasting charge recombination.

Visible and infrared solar radiation upconversion for water splitting via a surface plasmon-passivated strategy

“…The TA results (Fig. S4c and d, ESI†) reveal the charge transfer process, which is kinetically consistent with the Marcus inverted region 41 (for detailed analyses see the ESI†). Furthermore, this mechanism was investigated over a longer time scale using electron paramagnetic resonance (EPR).…”

Electronic Mechanism of In Situ Inversion of Rectification Polarity in Supramolecular Engineered Monolayer

“…Indeed, it made it possible to achieve in situ inversion of polarity in molecular rectification. (iii) Our work adds to the repertoire of a handful of examples of Marcus inverted charge transport in molecular junctions, reported by Nijhuis, , and other solid-state devices. − (iv) The response of MO energy levels to an external electric field, as shown in this work, may provide insights into various research areas at the interface with electrochemistry, including electrosynthesis, electrocatalysis, electrodetection, and electrochemical spectroscopy …”

Optimized photoelectric conversion properties of PbS x Se1−x -QD/MoS2-NT 0D–1D mixed-dimensional van der Waals heterostructures

“…Unlike Auger-assisted mechanism, in which the excessive charge transfer driving force can be used to excite another Coulomb-coupled charge, the Marcus inverted region exhibits the energy-wasting carrier recombination process. As displayed in the inset of figure 3(c), there are two steps in Marcus inverted region, i.e., charge transfer process (step I) and charge recombination process (step II) [47,48]. Clearly, the charge recombination process is followed immediately after the charge transfer in the case of large driving force (i.e., inverted region), resulting in a decreasing charge transfer rate with driving force.…”