Photoconversion device with enhanced photon absorption

Abstract

An infrared photoconversion device comprising a collector with at least an active layer made of a single sheet of doped single-layer, bilayer, or multilayer graphene patterned as nanodisks or nanoribbons. The single sheet of doped graphene presents high absorbance and thus, the efficiency of devices such as photovoltaic cells, photodetectors, and light emission devices can be improved by using graphene as the central absorbing or emitting element. These devices become tunable because their peak absorption or emission wavelength is changed via electrostatic doping of the graphene.

Description

TECHNICAL FIELD[0001]The present invention relates to photoconversion devices such as photovoltaic cells, photodetectors and light sources.BACKGROUND OF INVENTION[0002]Light absorption plays a central role in optical detectors and photovoltaics. Inspired by nature, two different routes have been investigated to achieve perfect absorption. A first one consists in relying on diffusion in disordered lossy surfaces (e.g., black silver and carbon). Engineered materials have been synthesized following this solution to produce extraordinary broadband light absorption (e.g., dense arrays of carbon nanotubes). A second approach consists in using ordered periodic structures, as found in some nocturnal insects, where they produce the moth eye effect. This alternative has been pioneered by experimental and theoretical work showing total light absorption (TLA) in the visible using metallic gratings. In this context, the Salisbury screen (U.S. Pat. No. 2,599,944 B1), consisting of a thin absorbin...

AI Technical Summary

Benefits of technology

[0003]The present invention relates to photoconversion devices such as photovoltaic cells, photodetectors and light sources. In particular, the invention provides devices in which higher light absorption, or more efficient light emission can take place thanks to a single or multi-layer sheet of patterned and doped graphene. In addition, the devices of the invention also provide optimum thermal emission occurring at specific wavelengths that are selected by means of applied electric fields. And finally, it provides devices that utilize the infrared part of the solar spectrum to optimize conversion into electrical signals for improved solar cells.

Problems solved by technology

However, due to the specific material properties, none of these technologies have enabled conversion from absorbed light into electrical signals, or have been very inefficient as such.

Additionally, these devices did not exhibit in-situ tunability of the absorption spectrum, neither emission frequencies in the infrared or THz range.

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