Project

Discipline

nanoscale photonics; molecular beam epitaxy; nanowires; nanowire-based solar cells; next generation solar cells; III-V semiconductors

Lead
Application des nanofils semiconducteurs pour des célules solaires de prochaine génération
Lay summary
Le développement de la technologie photovoltaïque des dernières décennies laisse voir ce domaine comme une vraie alternative aux sources fossiles de combustible. La technologie dominante au jour d’aujourd’hui est le silicium, même si le rendement est limité autour du 25%, ce qui est loin de la limite théorique pour des dispositifs à une seule jonction. Il a été proposé que des matériaux en forme de nanofils pourraient permettre d’augmenter le rendement, grâce à ses propriétés d’interaction avec la lumière. Dans ce projet on aimerait répondre à certaines questions afin d’avancer dans l’utilisation de nanofils semiconducteurs pour l’application dans des cellules solaires de prochaine géneration. Ces questions concernent : 1) la fabrication des réseaux de cellules solaires uniques à nanofils et identiques entre elles, 2) démonstration des avantages des nanofils pour ce genre de dispositif.

Direct link to Lay Summary

Last update: 12.06.2017

Active participation

Number	Title	Start	Funding scheme

In the last decades research on solar energy conversion has created an industrial technology that allows one to confront the ending of fossil fuels. Silicon solar cells dominate the market but still their efficiency is limited to values around 25 %, far from the theoretical limit for single material solar cells. Scientists have proposed alternative materials and/or concepts that can reach higher efficiencies, known as next generation solar cell concepts. In this proposal we aim at answering fundamental questions that will enable the exploiting semiconductor nanowires for an advanced solar cell technology.Semiconductor nanowires are filamentary crystals with a tailored diameter in the range from few to few hundred nanometers. Their shape and dimensions result in photonic properties that are of great advantage in solar cells. Although important progresses have been made, their potential has not yet been completely uncovered. In this proposal we intend to address two of the main issues that directly affect the energy conversion in nanowire based solar cells: surface recombination of photo-generated carriers and the positioning of nanowires in an optimized array structure. These two aspects hinder so far a high efficiency in nanowire-based solar cells. In particular, we will address the following questions:•Is it possible to obtain arrays of identical nanowire pn junctions, positioned deterministically on a substrate by a bottom-up approach?•Do the photonic properties of the nanowires translate into a higher open circuit voltage than for the equivalent planar devices? •Is it realistic to achieve an efficiency above the so-called Shockley-Queisser limit?We will provide an answer of whether nanowire arrays obtained in a bottom-up fashion can catch up with the expectations they have created and surpass the theoretical limit originally derived for single-bandgap solar cells by Shockley and Queisser (Shockley Queisser limit).