Researchers from Rice University and Los Alamos National Laboratory have observed electronic properties of perovskites at the quantum scale, and made discoveries likely to impact the development of perovskite solar cells.
The team has developed a scale to determine the binding energy of excitons, and thus the bandgap structures, in perovskite wells. This scale, according to Rice University, could assist scientists in developing new semiconductor materials.
“Understanding the nature of excitons and generating a general scaling law for exciton binding energy is the first fundamental step required for the design of any optoelectronic device, such as solar cells, lasers or detectors,” said the team.
Materials in the study were synthesized in a lab at Northwestern University, and brought to Rice University’s lab where they were exposed simultaneously to ultra-low temperatures, high magnetic fields and polarized light – achieved using the lab’s unique spectroscopy tool Rice Advanced Magnet with Broadband Optics (RAMBO). Combined with a computer model, the experimentation allowed the researchers to create a scale predicting exciton binding energies in 2D or 3D perovskites at any thickness.
“This work represents a fundamental and nonintuitive result where we determine a universal scaling behavior for exciton binding energies in Ruddlesden-Popper 2D hybrid perovskites,” the researchers said. “This is a fundamental measurement that has remained elusive for several decades, but its knowledge is critical before the design of any optoelectronic devices based on this class of materials and may have implication in the future for design of, for example, zero-threshold laser diodes and multifunctional hetero-material for optoelectronics.”