New pathway to turn sunlight into electricity

An spectroscopy experiment at University of Oregon has opened a window on how sunlight can be converted into electricity.

Using four pulses of laser light on nanoparticle photocells, the work could inspire devices with improved efficiency in solar energy conversion.

Spectroscopy is all about light and molecules and what they do together. It is a really great probe that helps to tell us about the reaction pathway that connects the beginning of a chemical or physical process to its end.

In the process, each single photon or particle of sunlight that is absorbed potentially creates multiple packets of energy called excitons.

These packets can subsequently generate multiple free electrons that generate electricity in a process known as multiple exciton generation (MEG).

In most solar cells, each absorbed photon creates just one potential free electron.

Multiple exciton generation is of interests because it can lead to solar cells that generate more electrical current and make them more efficient.

The University of Oregon work shines new light on the little understood process of MEG in nanomaterials.

"While the potential importance of MEG in solar energy conversion is under debate by scientists, the new spectroscopy experiment - adapted in a collaboration with scientists at Sweden's Lund University - should be useful for studying many other processes in photovoltaic nanomaterials," explained Andrew H Marcus, professor of physical chemistry.

The study appeared online in the journal Nature Communications.