Today, 85% of humankind’s energy demand is met by burning fossil fuels which release CO2 into the earth’s atmosphere. Growth in population and in GDP per capita will double global energy demand by 2050. There exists an urgent need for clean, cost-effective, robust solutions to this escalating societal and environmental crisis. Solar energy harvesting by using silicon-based photovoltaic has seen steady progress since work began four decades ago and it is approaching its theoretical limit of efficiency.

Stacking solar cells with decreasing bandgaps to form tandems offers an avenue to overcome the single-junction Shockley-Queisser limit in photovoltaics. The rapid development of perovskite-based solar cells (PSCs) is further enabled through the use of low-cost, solution-based coating methods to deposit high-quality wide-bandgap semiconductors. These properties make PSCs attractive as top cells for tandem applications that use different lower bandgap bottom cells.

The group research efforts bridge broad Chemistry, Physics, and Engineering disciplines, and are primarily focused on materials, assembling, and device innovation for perovskite-based tandem solar cells. Our research directions consist of three main thrusts:

1. Materials innovation

The core of this thrust is materials innovation for enabling new functionalities in devices. We primarily focus on developing new wide-bandgap perovskites absorbers, interface materials, flexible electrodes, self-assembled monolayers, 2D materials, and metal oxides with the potential for more efficient and stable conversion from solar to electricity.

2. Emerging structures and assembling processes

We explore new schemes of manipulating, processing, and assembling materials to create new and unexpected optical and electrical properties. We will develop a set of highly reproducible, inexpensive, and fast processing techniques that are compatible with large scale and high-throughput fabrication in the solar industry.

3. Tandem solar cells

In this thrust, we integrate the learnings from the above thrusts into perovskite-tandem solar cells with reliable, efficient, and inexpensive approaches. To harness solar energy, we innovate difference tandem architectures, new recombination junctions, electrical contacts, TCOs, passivators, and encapsulants in tandem solar cell and aim for a more broadly accessible future energy generation solution.