News & Posts

Archive 

04-5-2021 Thanks to NBC and NECN for giving me the chance to talk about how solar energy can help combat climate change and also showcase some of GridEdge Solar’s work.

05-27-2020 Had a lot of fun guest editing a special issue for the Journal of Luminescence focused on the Colourful Luminescence of Metal Halide Perovskites – from Fundamentals to Applications. It’s a collection of 26 peer-reviewed papers focused on uncovering the microscopic origins of photoluminescence blinking, ion migration, and also explores new synthetic procedures incorporating highly emissive films into unique composite structures.

05-11-2020 Just publicly released MATLAB code on GitHub for calculating non-radiative loss and external luminescence quantum efficiency in perovskite solar cells through a collaboration with talented grad student Lisa Krückemeier (Forschungszentrum Jülich). Hoping the PV community uses it to help standardize reporting of open circuit voltage losses.

04-23-2020 Our GridEdge team just had what I would consider to be one of our most important papers come out in Joule. We quantify lead leaching in perovskites PVs and place them in the context of lead regulation laws in the US and EU.

04-18-2020 Been exploring different kinetic models for modeling diffusion in emerging semiconductors. The mean squared displacement models are really interesting but only work some of the time! Thoughts captured in a recent paper posted on arXiv.

04-17-2020 New paper on maximizing the external luminescence quantum efficiency of perovskite solar cells is out in Pure and Applied Chemistry. Thanks to IUPAC for motivating me to try and condense my PhD thesis into a few pages.

12-03-2019 Looking forward to using Forbes as a platform to advocate for transitioning our society to solar energy.

10-18-2019 I have been looking forward to visiting the King Abdullah University of Science and Technology (KAUST) for a while, feeling honored to be able to make the trip over as an invited speaker at the 2020 Solar Research Conference.

09-09-2019 Very excited to get to share this work on the interesting recombination pathways in perovskites with the broader scientific community.

07-10-2019 Our work looking at photon recycling in operating perovskite photovoltaics was chosen as an Editor’s Suggestion!

01-24-2019 Working with fellow members of the GridEdge Solar team, we studied how the operating voltage of perovskite solar cells can be enhanced by harnessing photon recycling. The work was just posted on arXiv and submitted as well!

09-24-2018 Honored to be sought out by Nature to discuss my passions and goals to make light-weight, flexible perovskite solar panels to provide energy access to rural populations worldwide. It was also picked up by Scientific American!

07-25-2018 A press release on our surface passivation work from the spring came out in UW Today!

04-30-2018 Our work on surface passivation of perovskite semiconductors with Ian Braly and the Hillhouse lab at UW just came out in Nature Photonics! We fabricated some of the most emissive films to date and demonstrated the lowest thermodynamic loss for these materials!

04-27-2018 Excited to have the opportunity to travel to Paris and share my thesis research, thanks IUPAC-Solvay!

Posts

The Terawatt Challenge in Renewable Energy Generation

The replacement of finite fossil fuels with renewable sources of energy is one of the largest challenges facing the next century of industrialized human activity and is a necessary transition to ensure global welfare. Not only does the transition to carbon free sources of energy have major implications in the impediment of climate change and keeping our planet habitable, but is critical to continue supporting the systems for generating clean water, maintaining clean cooking facilities, making the fertilizers that grow food, powering the hospitals that provide healthcare, reducing air pollution, and powering the schools and equipment that form the basis of our education system. Although of massive importance now, this will become even more critical as the world population increases and the 1.2 billion people worldwide that currently do not have access to electricity will seek the most inexpensive routes to become electrified.1,2

To address this global energy challenge, we need to develop a vast infrastructure of renewable energy production, storage, and distribution. Although there are several promising avenues in shifting our society toward renewable sources, prerequisites in the replacement of existing technologies are scalable to terawatts, carbon-free, highly efficient, and low-cost. These types of technologies paired with continued research and investment, resilient energy policies, and effective grid integration are all critical factors that will play into the eventual success and continued prosperity of humankind.

Photovoltaic modules, which convert sunlight directly into electricity, provide a rather elegant solution to contribute to our growing energy demands as they have proven to exhibit long operational lifetimes due to their low maintenance requirements from no moving parts. Apart from this distinct advantage, the solar resource is a widely under-utilized source of energy. For example, by performing a simple calculation taking into account the power density at the surface of the sun (treated as a black body source), the angular range of the sun upon the earth, the attenuation of the radiation by the atmosphere, one can calculate the average integrated irradiance upon the earth’s surface. This is often defined as airmass 1.5 (AM1.5), which equates to an integrated irradiance of 1000 W/m2. To put this value in perspective, the average power consumed globally is 18.3 TW-year per annum, the total amount of power that hits emerged continents on earth is 23,000 TW-year per annum, whereas the total amount of known coal reserves on planet earth is estimated to be only 830 TWy.3 Using these values, it can be approximated that 13 days worth of energy from the sun is equivalent to the total energy reserves of coal that is currently known to exist.

Our ability to utilize this vast resource has been underwhelming in the last several decades. Currently solar energy contributes only 272 GW,4 a small fraction to global power production and consumption (18.3 TW). The hurdles in achieving TW production from solar lies largely in scalability and reducing the dependency on incentive programs and other project finance structures. For example, the success of photovoltaic installation in Germany and Japan is largely attributed to feed-in tariffs and associated policies,4 although more recently both countries have encountered financial as well as grid constraints which has slowed the continued expansion.

In order to achieve TW scale photovoltaics some of the future directions include 1) improving the performance of modules and 2) reducing the cost and time required to manufacture and install photovoltaics. Currently, silicon dominates ~93% of total PV production, largely due to the rapid drop in module prices over the past few years, and will continue to significantly contribute to energy production in the coming decades. One major drawback for silicon based photovoltaics that will eventually limit its growth and deployment is the high capital expenditure (capex). This term broadly encompasses the upfront cost to build a factory and to fill it with equipment.5 The capex for c-Si has been approximated to be $1/W-year, which equates to ~$1 billion to build a plant capable of producing 1 GW/year. On the other hand, a solution-processed material has potential to reduce capex to $0.06/W-year, which equates to ~$60 million to build a plant that can generate the same 1 GW/year.5 Therefore, capex innovation may be one of the most promising avenues, apart from increasing module efficiency, to achieve TW-scale photovoltaics.

Harnessing more energy from the sun not only requires basic scientific research in developing new materials and solar panels with long operational lifetimes, but an expansion in module production capacity, long-term energy storage, resilient energy policies, as well as an environmentally conscience global population determined to cleanly power the generations to come.

References

  1. International Energy Agency. Energy and Air Pollution, World Energy Outlook 2016 Special Report. (2016).
  2. King, D. Global clean energy in 2017. Science 355, 111, doi:10.1126/science.aam7088 (2017).
  3. Perez, R. a. P., M. A Fundamental Look at Energy Reserves for the Planet. IEA-SHCP-Newsletter 62 (2015).
  4. Haegel, N. M. et al. Terawatt-scale photovoltaics: Trajectories and challenges. Science 356, 141-143, doi:10.1126/science.aal1288 (2017).
  5. Powell, D. M. et al. The capital intensity of photovoltaics manufacturing: barrier to scale and opportunity for innovation. Energy Environ. Sci. 8, 3395-3408, doi:10.1039/c5ee01509j (2015).