Learning how to control the movement of electrons on the molecular and
nanometer scales could help scientists devise small-scale circuits for
many applications, including more efficient ways of storing and using
solar energy. Marshall Newton, a theoretical chemist at Brookhaven Lab
has been researching theoretical techniques used to understand the
factors affecting electron movement.
"Electron transfer plays a vital role in numerous biological
processes, including nerve cell communication and converting energy
from food into useful forms," says Newton. "It’s the initial step in
photosynthesis, as well, where charges are first separated and the
energy is stored for later use – which is one of the concepts behind
energy production using solar cells."
Newton will describe how combining electronic quantum mechanical
theory with computational techniques has led to a unified, compact way
to understand the nature of charge transfer in complex molecular
"In essence," he explains, "the research has led to understanding
electronic transport in terms of quantitative answers to a few basic
mechanistic questions: namely, how far, how efficiently, and by which
route (or molecular ‘pathway’) a charge moves from a ‘donor’ to an
‘acceptor’ in the molecular assembly." The answers come from detailed
molecular quantum calculations of the energy gaps separating the
relevant electronic states, and the strength of coupling between
adjacent molecular units along the "pathways."
"This new approach may yield ways to predict and control electronic
transport behavior by ‘tuning’ the molecular components, resulting in
capabilities that can be used to design new solar-based energy
schemes," Newton said.
This research was presented at The March 2008 American Physical Society Meeting in New Orleans, La., March 10 -14.
Source: DOE/Brookhaven National Laboratory. March 2008.