Liquid Sunlight Alliance Research at NREL (Text Version)

This is a video about NREL's research for the Liquid Sunlight Alliance (LiSA). 

Video opens with an aerial shot of the NREL campus. 

Located in the foothills of Golden, Colorado, the National Renewable Energy Laboratory focuses on finding creative answers to today's energy challenges. From breakthroughs in fundamental science to new, clean technologies and integrated energy systems that power our lives, NREL researchers are transforming the way the nation and the world use energy.

Shot of Bill Tumas, community alliance coordinator for LiSA, speaking.

"We're really excited at NREL to be key partners in the Liquid Sunlight Alliance, LiSA. We believe LiSA will fundamentally transform the field of artificial photosynthesis to harness solar power to directly produce fuels and chemicals."

"We also think LiSA will have broad impacts across the chemical and material sciences field as well as other energy science areas. NREL will bring distinct and diverse capabilities and expertise to LiSA that can help capture the potential benefits of directly coupling solar energy with chemical transformations."

Shots of photovoltaic (PV) cell, shot of researcher holding a PV cell, a laboratory, a researcher in a laboratory.

"For example, we bring capabilities in the materials science of photo absorbers that include both new materials as well as tandem concepts. We also bring approaches to create and understand micro environments for chemical transformations. And we bring decades of expertise in solar photochemistry, photoelectric chemistry, the design of solar energy conversion systems, and characterization at the materials, device, and system level."

Slide showing Phase I components: photocatalysts, molecular catalysts, heterogeneous catalysts, membranes and polyelectrolytes, molecular additives, redox shuttles, gas diffusion layers, electrolytes, and bipolar membranes.

The project includes three phases. Phase 1, which will focus on components making up a solar fuels generating system, from the light capture and charge separating semiconductors to the catalysts and species controlling spin. Phase 2, which assembles these individual components into micro environments, where emergent phenomena occur as a result of their assembly. 

Slide showing Phase 2 environment assemblies: H+, OH-, H₂0 management; photocatalyst; separation and transport; molecular photocatalyst, modifier, or shuttle; and catalytic reaction center. 

Phase 2 will use codesign principles to evaluate the micro environment assembles to understand these emergent phenomena and lay the groundwork for designing the sequential catalytic processes needed to generate liquid solar fuels.

Slide showing Phase 3 systems of environment assemblies: molecular photocatalyst, modifier, or shuttle; catalytic reaction center; CO₂; C_XH_YO_Z; separation and transport; H+, OH-, H20 management; photocatalyst, and sunlight. 

Phase 3, which studies codesign and characterization of complex systems of micro environment assemblies that perform sequential catalytic steps necessary for generating solar fuels, all in a monolithically integrated reaction environment.

Shot of Sage Bauers, researcher, speaking.

"In LiSA, we are synthesizing complex alloys catalytically active photo absorbers, where the number of compositions to evaluate is too vast to reasonably tackle by conventional approaches. NREL has a long history of discovering and developing new photo absorber and charge transport layers for thin film photovoltaics. This has led us to build several state of the art high throughput thin film deposition systems based on combinatorial sputtering and pulsed laser deposition."

Shots showing researcher's hands holding a material sample and adjusting lab equipment, inside the equipment, a researcher looking inside the equipment, and of Sage Bauer speaking again. 

"These tools enable us to rapidly survey growth parameters from large regions of chemical space from across the periodic table. Growth is followed by high throughput measurement of the suite of properties required for solar fuels materials, including light absorption, catalytic activity, operational stability, and charge carrier transport. This approach will allow us to efficiently isolate and optimize the most promising photocatalytic materials for detailed follow-on study by LiSA."

Shot of Adele Tamboli, co-principal investigator, speaking. 

"NREL has world class semiconductor epitaxy capabilities, including metalorganic chemical vapor deposition, which is used to grow the world's highest efficient multijunction solar cells. We can use these techniques to grow complex device architectures, such as three terminal tandems, to drive multi-step CO₂ reduction reactions to liquid fuels in a process known as cascade photocatalysis." 

Shots of solar cells, researcher with lab equipment, a glowing glass tube encircled by thick copper wire, and two researchers talking and working in a lab.

We can also use molecular beam epitaxy to grow high quality photo absorber materials in heterostructures. This is a more flexible technique for demonstrating novel materials. Using these tools, we can bridge the gap between materials discovery and demonstrating the next generation of high performance photo absorbers for solar fields.

Shot of Nate Neale, co-principal investigator, speaking.

"NREL will use model semiconductor nanoparticles to understand the rare events that lead to photo corrosion, in collaboration with scientists at SLAC, LBNL, and Caltech. This is NREL's plasma-enhanced chemical vapor deposition, or PECVD system, that can grow a range of intrinsic and doped semiconductor nanoparticles that are difficult to synthesize using colloidal approaches, such as silicon, germanium, and three-fives, such a gallium indium phosphide."

Shots of researchers in a lab, an activated laser, PECVD lab equipment, and 3D image of a material's molecular structure.

"This PECVD instrument uses gas and organometallic precursors similar to what you'll find in the semiconductor growth industry, just as a research scale. our PECVD system has an intricate series of pneumatic valves, mass flow control devices, and temperature and pressure controllers that can deliver essentially any volatile molecular precursor to the reaction chamber."

Shot of Nate Neale, co-principal investigator, speaking.

"We plan to modify the surface chemistry of these PECVD-grown nanoparticles and leverage their high surface to volume ratios to allow us to understand the first steps in photo corrosion, using synchrotron-based time result x-ray experiments at SLAC and LBNL."

Shot of Wilson Smith, co-principal investigator, speaking. 

"The activity and selectivity of electrochemical reactions are significantly influenced by their location reaction environment, including the composition of the electrode and electrolyte."

Shots of lab equipment.

"Using operando spectroscopy and microscopy, we will probe the micro environment of catalysts during electrolysis for a variety of chemical reactions, including water splitting and CO₂ reduction."

Shot of Wilson Smith, co-principal investigator, speaking.

"Through LiSA, we will partner with computational and experimental groups to determine the optimal local conditions to drive efficient and selective electrocatalysis."

Shot of Emily Warren—team lead for systems and integration, and co-principal investigator—speaking. 

"NREL has two separate clean room facilities with a total of 3,750 ft² of Class 100 and Class 1000 lab space dedicated to semiconductor processing and metrology. Our fabrication tools include chemical hoods, mask aligners, nanoimprint lithography, physical vapor deposition, and reactive ion etching."

Shots of lab equipment and researcher working in a lab. 

"Our metrology tools include laser confocal microscopy, optimal microscopy, and ellipsometry. We also have a dedicated silicon clean room with 156 millimeter tool set for full size solar cell processing."

Aerial shot of NREL's campus buildings. 

Together, all of these capabilities at NREL will help the Liquid Sunlight Alliance establish a scientific foundation for next generation solar fuels.