Researchers pioneer new window architecture making solar energy collection more efficient

Window panes that use engineered quantum dots to split and absorb different parts of the solar spectrum can be used to help reduce solar electricity costs, researchers at Los Alamos National Laboratory announced on Tuesday.

Researchers pioneered a double-pane window architecture that incorporates two varieties of designer quantum dots. The quantum dots have been found to generate electricity more efficiently and provide shading.

“Because of the strong performance we can achieve with low-cost, solution-processable materials, these quantum-dot-based double-pane windows and even more complex luminescent solar concentrators offer a new way to bring down the cost of solar electricity,” Victor Klimov, a lead researcher at Los Alamos National Laboratory, said. “The approach complements existing photovoltaic technology by adding high-efficiency sunlight collectors to existing solar panels or integrating them as semi-transparent windows into a building’s architecture.”

Researchers identify “solar-spectrum splitting” as a core element of the breakthrough. It allows for the separation of higher- and lower-energy solar photons. Higher-energy photons are capable of generating a higher photovoltage, which drives total power output.

“To achieve this, the Los Alamos team incorporates into quantum dots ions of manganese that serve as highly emissive impurities,” a Los Alamos National Laboratory release stated. “Light absorbed by the quantum dots activates these impurities. Following activation, the manganese ions emit light at energies below the quantum-dot absorption onset. This trick allows for almost complete elimination of losses due to self-absorption by the quantum dots.”

A layer of highly emissive manganese-doped quantum dots are placed on the fronts of glass panes, and copper indium selenide quantum dots are placed on the backs of glass panes. While the manganese-doped quantum dots absorb blue and ultraviolet solar light, the copper indium selenide quantum dots absorb the rest of the spectrum.

After absorption, the light is re-emitted to edges of the panes for collection by solar cells.