Technology Commercialization and Partnerships | BSA 08-26: Nanopillar Electrodes for Efficient Organic Solar Cells

Print Friendly

Categories: advanced materials, energy

BSA 08-26: Nanopillar Electrodes for Efficient Organic Solar Cells

BNL Reference Number: BSA 08-26

Patent Status: Application Number 20110248315 was published on October 13, 2011

Summary

Nanopillared electrodes on top and bottom reduce the distance carriers (open and closed circles) must travel from an interface to an electrode.

New photovoltaic cells increase sunlight-to-electricity conversion efficiency by using an electrode structure that reduces the distance charge carriers must travel. Designed primarily for organic bulk heterojunction (BHJ) solar cells that contain two types of semiconductors in a disordered mixture, the electrodes can easily replace lower-efficiency planar electrodes at the same cost.

Description

An optoelectronic device contains two major components: a photoactive layer with a heterojunction; and electrode(s) with an electrically conductive base and electrically conductive pillars extending into the photoactive layer. These BHJ photovoltaic cells are formed by sandwiching two semiconducting materials, one p-type and one n-type, between two electrodes. Charge carriers are produced at the junction between semiconductor types and diffuse toward an electrode where they can be harnessed to produce electricity. The inventive nanopillared electrodes reduce the distance charge carriers must travel to encounter an electrode, thus increasing efficiency, particularly for devices using materials with low carrier mobility.

Benefits

These new electrode nanopillars reduce charge carrier transit time, allowing for thicker light-absorbing layers without increasing the recombination of electron-hole pairs, making the photovoltaic cell much more efficient than alternative organic cells. They are inexpensive to produce, using bottom-up techniques and organic semiconductors. The same electrode architecture can be applied to other devices with low carrier mobility.

Applications and Industries

While specifically described with reference to BHJ photovoltaic cells, the new nanopillar electrode principle can be applied to other types of solar cells that employ active materials with low carrier mobility.