Researchers from Russia's Kazan Federal University have reported on a new method for the fabrication of polypropylene/metal halide perovskites composite in one single step by co-extrusion of the perovskite precursors with polypropylene. Perovskite quantum dots are formed in-situ, and are uniformly distributed in the polymer matrix.
The team said that the material demonstrated high quantum yield and unprecedented stability at ambient conditions. The team further demonstrated that an extruded strand can be used directly as a filament for 3D printing technology. The developed method is simple, has literally no waste, and is unlimitedly scalable. It offers a way to efficiently solve the problem of stability of perovskites, simultaneously involving them into additive manufacturing technologies.
Project lead, Lead Research Associate of the Laboratory of Prospective Carbon Nanomaterials Ayrat Dimiev, explains, "On the one hand, our research is fundamental, on the other hand, it has applied value. Perovskites are a class of compounds that are very fashionable in the modern scientific world, as they have unique photoluminescent properties, but they have one drawback—they are not stable under normal conditions. The humidity of the air mercilessly destroys them, which leads to the loss of luminescent properties. To prevent this, various works are being carried out to stabilize them. One of the proposed methods is the encapsulation of perovskites in a protective material—glass or polymer—i.e. their isolation from external conditions. However, no significant progress has yet been made along this path."
"Synthesis of perovskites occurs directly in the extruder, where the polymer is loaded to draw the thread. Previously, the process of obtaining such composites included a number of labor-intensive stages: starting with the rather complex synthesis of perovskites themselves with their isolation and purification, and ending with the subsequent multistage and labor-intensive introduction of perovskites into a polymer. The last stage included the dissolution of the polymer in an organic solvent and its subsequent distillation. In our method, the composite is synthesized in one step and 'in one glass' in full accordance with the principles of green chemistry and sustainable development. The resulting composite has high heat and moisture resistance, can be directly used for 3D printing by FDM at a temperature of 200-220 degrees under ambient conditions. The developed method is simple, has virtually no waste, and is scalable indefinitely," continues Dimiev. "Phosphors used today in LEDs contain expensive rare earth metals such as yttrium and cerium, but we offer another material that is cheaper and more efficient. Perovskites are also relevant for photovoltaics; in laboratory samples, the highest photoelectric conversion coefficient today is achieved using perovskites."
