Colloquium: Esther Alarcón Lladó - Managing light and matter at the nanoscale towards high efficiency solar energy conversion
NanoScience Colloquium 15 by Prof. Esther Alarcon Llado (https://amolf.nl/people/esther-alarcon-llado) hosted by Magnus Borgström.
The pre-discussions with the local PhD students will be at 14.00 - 14.30
Managing light and matter at the nanoscale towards high efficiency solar energy conversion
Nanostructured metals and semiconductors are promising building blocks for next generation solar energy conversion, including solar cells and solar fuel devices, as they offer a plethora of unique light-matter interactions and can be potentially made with low-cost fabrication methods. From the optical perspective, nanostructure (NS) ensembles constitute a new class of metamaterial, where the optical properties (light absorption, transmission and scattering) of the ensemble are ruled by the NS geometry and collective arrangement. From these properties, a new variety of solar cell designs emerge, that are not possible in the bulk form.
In my group, we particularly focus on waveguiding phenomena that can lead to new high efficiency solar cell designs while minimizing material usage and/or enabling new additional functionalities. As an example, we have used the waveguiding characteristics in thin semiconductor nanowires to design new optically smart tandem solar cells with just a fraction of raw material, or even to create a new type of colorful solar cells with minimal current losses. As another example, we have recently demonstrated the highest absorption in 1 µm Si slabs by using rationally designed nanopatterns that maximize broadband coupling to waveguide modes.
Despite the great potential for such nanostructured architectures for PV, the still ongoing challenge for nanoscale solar energy devices is how to cost-effectively fabricate large area NS arrays on a substrate. In our group we also develop new methods for the nanoscale control over electrochemical deposition as an emerging low-cost tool for nanomaterial fabrication. We have shown the successful nanostructure growth of various materials, from InAs to various metals, and from a single nano-structure to large area arrays.
 Tavakoli, N. et al. Over 65% Sunlight Absorption in a 1 μm Si Slab with Hyperuniform Texture. ACS Photon. 9, 1206–1217 (2022).
 Tavakoli et al., Coloured and semi-transparent nanowire-based solar cells for building-integrated photovoltaics, arXiv:2107.09465 (2021)
 Tavakoli, N. & Alarcon-Llado, E. Combining 1D and 2D waveguiding in an ultrathin GaAs NW/Si tandem solar cell. Opt. Express 27, A909 (2019)
 Valenti, M. et al. Grain size control of crystalline III–V semiconductors at ambient conditions using electrochemically mediated growth. J. Mater. Chem. A 8, 2752–2759 (2020).
 Aarts, M., Reiser, A., Spolenak, R. & Alarcon-Llado, E. Confined pulsed diffuse layer charging for nanoscale electrodeposition with an STM. Nanoscale Adv. 4, 1182–1190 (2022)..
 Aarts, M. & Alarcon-Llado, E. Directed nanoscale metal deposition by the local perturbation of charge screening at the solid–liquid interface. Nanoscale 11, 18619–18627 (2019)
 Frederiksen, R. et al. Visual Understanding of Light Absorption and Waveguiding in Standing Nanowires with 3D Fluorescence Confocal Microscopy. ACS Photon. 4, 2235 (2017).
After earning her PhD from the University of Barcelona in 2009, Dr. Esther Alarcon-Llado has been a postdoctoral fellow in Singapore (a*STAR Institute IMRE), Berkeley (LBNL) and Lausanne (EPFL), working in the groups of Prof. S. Tripathy, Prof. J. Ager and Prof. A. Fontcuberta i Morral, respectively. In 2016, she started the 3D Photovoltaics group at AMOLF bringing her three passions together in a laboratory that embraces optics, nanotechnology and electrochemical scanning probe microscopy. Dr. Alarcon Llado is thrilled by the power of their synergistic combination to understand and visualise nanoscale physical and chemical processes that have great impact on material science and renewable energy generation.