Riccardo Comin and Xiwen Gong at the University of Toronto examine a novel LED material that blends quantum dots into a perovskite matrix. Credit: Marit Mitchell
A team of materials engineers at the University of Toronto (Canada) has combined two promising novel solar cell materials in a way that allows them to emit infrared (IR) light more efficiently than other materials, which may enable record power efficiency in IR light-emitting diodes (LEDs; Nat. Lett., doi:10.1038/nature14563). Researchers in the lab of Ted Sargent blended colloidal quantum dots (CQDs) into a perovskite crystalline matrix to combine the benefits of both.
CQDs are a type of highly tunable, strongly luminescent nanoparticle with high radiative efficiency. Perovskite is an easy-to-manufacture semiconductor material with a large, crystalline structure, featuring efficient long-range electrical transport properties. Both materials have been useful in novel photovoltaic materials for solar cells. And both materials chosen by the researchers possess compatible crystalline structures.
Post-doctoral fellow Riccardo Comin and doctoral candidate Xiwen Gong were lead co-authors on the study, along with Zhijun Ning, previously a post doc at Toronto, now a faculty member at ShanghaiTech University (China). The team designed a new two-step strategy to effectively coax the two materials to blend smoothly into a unique crystalline thin-film. The strategy involved growing a nano-scale perovskite crystal scaffold around the inorganically terminated CQDs in solution, forcing the two atomic “ends” of the structures to align.
The new hybrid material is compatible with solution processing techniques that enable inexpensive and practical commercial manufacturing of solar photovoltaic film and devices. The group plans to build and test an LED device next, which they hope will beat existing power efficiency records.