Power-to-X: STREAMing Hydrogen from 3-Band Solar Cells boosted with Photonic Management

Introduction

X-STREAM will sprout a new era of sustainable power sources based on photovoltaic (PV) systems which are not bounded by fundamental limits that hamper the efficiency of conventional solar cells, and endowed with energy storage via a synergetic coupling with electrochemistry (EC).

Project Overview

This will be achieved via an unprecedented energy package integrating two disruptive advances:

1. Light Management
   Light management via quantum structuring amplified by photonic trapping, to create 3-band PV – a new trend that will be launched, realized with wide-bandgap nanostructured solar cells capable of pronouncedly converting photon energies below their bandgap, thus exploiting the broad solar spectral range. This will allow, for the first time, to increase the efficiency of single-junction PV towards a 50% theoretical maximum, which is close to the limiting efficiency of triple-junction cells but here is attained with a single-junction.

2. Smart Combination of Technologies
   Smart combination between PV cells and EC flow cells, in compact PV-EC devices that deliver the energy in hydrogen (H2) fuel synthesized from water splitting, enabling close to 30% solar-to-H2 efficiency with high operation stability, by capitalizing on:
   a) high voltage per junction of the 3-band PV technology, which is favourable to drive the EC reactions;
   b) thermal coupling between PV and EC in single devices, which naturally provides heat management of both systems.

Targeted Fuel

The targeted fuel is a highly convenient energy vector in view of the present European urgency for a resilient, competitive, and environment-friendly H2 economy.

Industrial Deployment

All the project developments will be attractive for industrial deployment, since mostly Earth-abundant materials and scalable processes are applied, so that the PV-EC prototypes can be easily customized and scaled for different uses.

Expertise

The expertise of the PI team and his network of collaborators in nanotechnology, multi-band PV, photonics for light trapping, and solar fuels via PV-EC, places him in the best position to realize X-STREAM goals.