Modeling the interaction between light, electricity and mechanics for a new generation of renewable-energy devices (MechanoPV)

Current solar cell technologies use semiconductors (prominently silicon), to convert light energy into electricity through the photovoltaic effect (PV). This effect faces thermodynamic constraints that can only be alleviated through complex and expensive material architectures, reaching efficiencies below 40%. Other energy materials, such as wide-bandgap ferroelectrics, can provide an alternative path to photovoltaic devices free from thermodynamic limitations, through the so-called bulk photovoltaic effect (BPV), but is fundamentally restricted to non-centrosymmetric materials,
which suffer from very low light absorption properties, achieving also low efficiencies.

In a breakthrough research result, Alexe and co-workers showed in 2018 that the polarization generated by strain gradients according to flexoelectricity can also be used to separate photogenerated charge pairs, and hence activate the BPV. Importantly, because this effect is not constrained to noncentrosymmetric materials, it enables the use of a much wider class of materials with high solar absorption. This new effect, termed flexo-photovoltaic (flexo-PV) effect, could lead to a new generation of efficient and cheap flexo-PV solar cells. However, the field lacks a theoretical and computational framework for light-electricity-mechanics couplings in materials to understand and predict in a unified manner the previous effects enabling solar power generation.

The main goal of the project is develop a quantitative computational tool based on sound physics for the engineering analysis of light-electricity-mechanics coupling in dielectrics, ferroelectrics and semiconductors, applicable to general geometries, boundary conditions, material layouts and finite deformations. This quantitative tool will allow us to understand and rationally design and optimize PV devices, which unleash the potential of mechanics in enhancing photovoltaic efficiency and enabling PV in new classes of materials (cheaper, more durable, etc).

Project PID2023-152533OB-I00, funded by MICIU/AEI/10.13039/501100011033 and FEDER, UE