Duke University scientists have developed a method to create hybrid thin-film materials, paving the way for a new class of solar cells, LEDs and photodetectors.
According to the researchers, methylammonium lead iodide (MAPbI3), the most commonly used perovskite in the solar industry today, can convert light to energy just as well as today’s best commercially available solar panels. And it can do it using a fraction of the material – a sliver 100 times thinner than a typical silicon-based solar cell.
Created using standard industry production techniques, it still has issues with scalability and durability.
To truly unlock the potential of perovskites, however, new manufacturing methods are needed because the mixture of organic – critical to the hybrid material’s ability to absorb and emit light effectively – and inorganic molecules in a complex crystalline structure can be difficult to make.
Now professor David Mitzi, and associate professor Adrienne Stiff-Roberts, have demonstrated a new manufacturing approach called Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation (RIR-MAPLE).
Adapted from a technology invented in 1999 called MAPLE, the Duke technique involves freezing a solution containing the molecular building blocks for the perovskite, and then blasting the frozen block with a laser in a vacuum chamber.
When a laser vaporizes a small piece of the frozen target about the size of a dimple on a golf ball, the vapor travels upward in a plume that coats the bottom surface of any object hanging overhead, such as a component in a solar cell.
Once enough of the material builds up, the process is stopped and the product is heated to crystallize the molecules and set the thin film in place.
In Stiff-Roberts’s version of the technology, the laser’s frequency is specifically tuned to the molecular bonds of the frozen solvent. This causes the solvent to absorb most of the energy, leaving the delicate organics unscathed as they travel to the product surface.
“The RIR-MAPLE technology is extremely gentle on the organic components of the material, much more so than other laser-based techniques,” said Stiff-Roberts. “That also makes it much more efficient, requiring only a small fraction of the organic materials to reach the same final product.”
Image and content: E. Tomas Barraza/Duke University