Scientists Turn Perovskite Materials into Light Sources for Quantum Communication
Researchers Shuyue Feng, left, and Zijian Gan, both Ph.D. students in the Moran Lab in the Department of Chemistry, have demonstrated a new way to encode information in light using a class of materials known as two-dimensional perovskites.
March 20, 2026 I By Dave DeFusco
Scientists have long imagined a future in which information could be sent using the smallest possible packets of light—individual photons—making communication far more secure than today’s internet. Now researchers in the Moran Lab in the Department of Chemistry at UNC-Chapel Hill have demonstrated a new way to encode information in light using a class of materials known as two-dimensional perovskites.
The work, “Nonlinear Optical Quantum Communication with a Two-dimensional Perovskite Light Source,” published in the Journal of Chemical Physics, shows how these materials can act as tiny light sources whose internal physics naturally shapes the signals needed for quantum communication.
Quantum communication relies on the idea that information can be stored in delicate properties of photons, such as the direction in which their electric field oscillates, called polarization. Because any attempt to intercept these photons introduce detectable errors in transmitted photons, the technique can allow two people to exchange secret encryption keys with built-in protection against eavesdropping.
In the study, the researchers used a special layered material called a two-dimensional organic–inorganic hybrid perovskite. Perovskites are crystals that have become famous in recent years for their potential in solar cells and light-emitting devices. The version used in this research forms extremely thin layers that trap energy in ways that strongly affect how light is emitted.
“These materials were not originally designed for quantum communication,” said Zijian Gan, one of the lead authors of the study and a Ph.D. student in chemistry. “People study them for many things such as solar cells and LEDs but when we looked closely at how the electrons behave after being excited by a laser, we realized their spin dynamics could naturally control the polarization of the light they emit.”
When a laser pulse hits the material, it excites pairs of charged particles called excitons. These excitons have a property called spin, which can be thought of as a tiny arrow pointing in a certain direction. As the spins relax and interact with one another inside the crystal, they change how the emitted light is polarized.
By carefully measuring those changes over incredibly short times—millionths of a billionth of a second—the team found they could control the polarization of the photons coming from the material.
“We track how the emitted light changes from an elliptical polarization to a linear polarization as the spins relax,” said Gan. “That difference gives us two clearly distinguishable photon states, which is exactly what we need to encode digital information.”
To observe these changes, the researchers used an advanced optical technique called four-wave mixing. In this method, several ultrafast laser pulses interact with the material, producing a new light signal that carries detailed information about what is happening inside the crystal.
Shuyue Feng, another lead author and a Ph.D. chemistry student, said the experiments revealed a surprising advantage. Features known as biexcitons—states formed when two excitons interact—amplified the optical signal and made the polarization differences stronger.
“That stronger contrast means we need fewer photons to transmit information,” said Feng. “In some cases, only around 10 photons are needed to send a single binary bit, which is much more efficient than other conditions we tested.”
To demonstrate the concept, the researchers implemented a quantum encryption scheme similar to the well-known BB84 quantum key distribution protocol. Instead of using conventional optical components to control photon polarization, their system relied on the natural electronic behavior of the perovskite material itself.
The team encoded a short message using the polarization states of photons emitted by the crystal. The message—an eight-character ASCII phrase totaling 56 bits—was successfully transmitted using the material’s light signals.
“This shows that the material’s internal physics can actually perform part of the job that normally requires complicated optical equipment,” said Andrew Moran, senior author of the study and a Carolina professor of chemistry. “The idea that a material can generate photons whose polarization already carries the encoded information is very exciting.”
Traditional quantum communication systems typically manipulate the polarization of light after it is produced, using devices such as wave plates and modulators. In the new approach, the polarization emerges directly from the interactions between electrons inside the crystal. That difference could eventually simplify quantum communication hardware.
“Instead of adding more components to control the light, we can let the material’s own spin dynamics define the signal,” said Moran. “This could lead to compact, efficient photon sources for quantum networks.”
Although the experiment was designed as a proof of concept, the researchers say the approach could be adapted to other materials with similar spin behavior. Their lab is already exploring semiconductor structures and quantum dots as possible platforms.
“Right now, we’re demonstrating the physics,” said Gan. “But the results show that materials like these could play a real role in future quantum communication systems.”