Florida State University chemists have solved a manufacturing bottleneck that has kept a promising class of radiation-detection materials stuck in the lab: films made from zero-dimensional organic metal halide hybrids (OMHHs) now survive prolonged exposure to water and polar solvents after a single UV-light curing step.

The findings, published in Advanced Functional Materials (DOI: 10.1002/adfm.78188), come from the lab of Biwu Ma, FSU professor of chemistry and biochemistry, who pioneered OMHH research nearly a decade ago. He worked with Joseph Schlenoff, Robert O. Lawton Professor of Chemistry and Biochemistry, and Subramanian Ramakrishnan, 3M Distinguished Professor of Chemical and Biochemical Engineering, on the stabilization technique.

The problem was fundamental. OMHHs combine organic and inorganic components whose optical, electrical and magnetic properties can be tuned through molecular design, making them candidates for LEDs, solar cells, direct X-ray detectors and scintillators — materials that convert X-rays or other high-energy radiation into visible light. But some OMHHs dissolve or degrade in water and common polar solvents, which blocks solution processing into stable, durable device structures.

The FSU team's fix works at the molecular-design level. They synthesized 0D OMHHs — materials in which individual metal-halide units are isolated from one another — and built reactive groups directly into the organic components. After solution-processing the material into a film, a blast of UV light connects those components into a covalent network, locking the isolated metal-halide units in place.

"Using a technique called crosslinking, we're shaping OMHHs before locking them into a more durable form," Ma said. "A familiar example is rubber in car tires. Crosslinking transforms rubber into a much more robust and durable material capable of withstanding demanding conditions. Our chemistry is different, but the fundamental idea is similar: Connecting individual molecular components into a network can dramatically improve the physical robustness and stability of a material."

The test results are stark. Uncrosslinked films dissolved quickly in water and other solvents. Crosslinked films remained intact after prolonged exposure. The material keeps its useful optoelectronic properties while gaining processability before curing and robustness afterward — a combination device manufacturers need.

Ma framed the work as a shift in priorities for his group. "A material may perform well as a small laboratory sample, but real-world applications require reproducible manufacturing, long-term stability, integration with other components, and competitive cost and performance," he said. "Our research is increasingly focused not only on discovering materials with better properties, but also on how those materials can be processed, stabilized, manufactured and integrated into practical devices. The crosslinking strategy is an important step in that direction because it addresses processability and stability at the molecular-design level."

Two graduate students carried the experimental load. Tunde Shonde, a former doctoral student in Ma's group now a scientist at BASF, ran the initial experiments that established crosslinking 0D OMHHs was feasible. Sahel Moslemi, a third-year doctoral student and the study's first author, developed the materials further and led most of the experimental work and characterization.

The collaboration extends toward additive manufacturing. Ramakrishnan and his team at the FAMU-FSU College of Engineering are exploring whether OMHHs could be processed with 3D-printing techniques, combining molecularly engineered materials with additive manufacturing to build functional devices — including radiation detectors with customized structures and technologies that could eventually be manufactured in space.

Schlenoff's lab, which specializes in polymer and surface chemistry, analyzed how crosslinking changed the properties of thin OMHH films, including how their surfaces interact with water. That analysis helped the team understand what drives the films' durability.

"Developing new materials can change what technologies are possible," Ma said. "The crosslinkable materials we created provide an interesting foundation for future developments. We envision applying our research to create printable formulations of OMHHs that can be deposited into customized patterns and 3D structures and then crosslinked to stabilize those structures. This could allow us to manufacture radiation detectors and other technologies with customized or complex structures for specific applications."

For now, the UV-cured films remain a research result rather than a product. But the demonstration that a solution-processable, solvent-sensitive detector material can be locked into a durable form in one curing step moves OMHHs closer to the reproducible, cost-competitive manufacturing that medical imaging, radiation therapy and space applications demand.