Molecular Glass from Solution Self-Assembly

Glass is a vital material across diverse fields including photovoltaics, construction, medicine, telecommunications, and display technologies. Beyond conventional inorganic, metallic, and polymeric glasses, recent developments have introduced new families, such as supramolecular glasses (SGs), which exhibit greater structural diversity, molecular tunability, and functional versatility. Formed through noncovalent interactions, SGs allow for the incorporation of a wide range of molecular components and architectures.

However, SG fabrication remains largely dependent on melt-quenching, a method that demands high temperatures, costly equipment, and complex procedures. Additionally, thermal decomposition of many components prior to melting limits the design space for new SGs. These constraints highlight the need for alternative low-temperature synthesis methods. To address this challenge, our group recently introduced a sustainable and bottom-up approach based on metal–histidine complexes, termed evaporation-induced self-assembly (EISA). This solution-based technique enables the efficient production of various SGs, including single- and multicomponent organic glasses and organic–inorganic hybrids.

In the EISA process, molecular precursors are first dissolved in a solvent to form a uniform solution. Controlled solvent evaporation─under ambient pressure and moderate temperatures─increases viscosity, impeding the orderly organization of monomers. Simultaneously, polymerization progresses, leading to vitrification and glass formation. This low-energy, equipment-free process eliminates the need for thermal treatment or postprocessing and allows for solution-based recycling, aligning with principles of green chemistry and sustainable materials development.

Compared with inorganic and metallic glasses, solution-processed SGs offer several key advantages, including low density, high transparency, recyclability, and superior processability. Their properties can be tailored through the incorporation of functional moieties, such as dye molecules or metal ions, enabling tunable photoluminescence. The rigid SG matrix effectively restricts molecular vibrations, resulting in ultralong room-temperature phosphorescence (RTP), while the addition of chiral components can generate circularly polarized luminescence (CPL).

SGs fabricated via EISA exhibit multifunctionality, making them suitable for a wide range of applications. Their intrinsic ability to self-assemble into varied morphologies is ideal for the fabrication of advanced optical elements. The high viscosity of precursor solutions during evaporation facilitates their use as transparent adhesives. Additionally, their prolonged RTP performance also makes them attractive for anticounterfeiting and information security technologies.

The continued development of solution-assembled SGs will depend on several critical advances: scalable manufacturing methods, the integration of sustainable bio-based components, enhanced mechanical durability and flexibility, and the expansion of functional building block libraries. These innovations are expected to broaden the utility and performance of SGs across a wide range of fields. With ongoing progress, solution-processed SGs are poised to drive the next generation of functional glasses in energy, electronics, displays, and beyond.