Solar panels and light-emitting diodes, for example, could become more environmentally friendly and durable as a result of research into the synthesis of new materials (LEDs). Using colloidal synthesis, researchers from Iowa State University and Ames National Laboratory were able to create alkaline earth chalcogenides. They can regulate the size of the nanocrystals in the material using this technique. They were also able to look at how pure the materials were and how they looked, as well as the chemistry of the nanocrystals’ surfaces.
Scientists are becoming more and more interested in the semiconductor class known as alkaline earth chalcogenides. They can be used for a wide range of things, including thermal sensors, LEDs, and bioimaging. Also, these things can be used to make optical materials, such as perovskites, which turn light into energy.
These new materials are interesting because, in the words of Javier Vela, an Ames Lab scientist and the John D. Corbett Professor of Chemistry at Iowa State University, “they are composed of earth-abundant and biocompatible elements, which makes them favorable alternatives compared to the more widely used toxic or expensive semiconductors.”
According to Vela, more widely used semiconductors contain lead or cadmium, both of which are harmful to the environment and human health. In addition, solid-state reactions are the most widely used method by scientists to create these materials. These reactions frequently take place at extremely high temperatures (above 900 °C or 1652 °F), he explained, and they can take days to weeks to complete.
Vela contrasted this by saying that “solution-phase (colloidal) chemistry can be performed using much lower temperatures and shorter reaction times (below 300 °C or 572 °F).” Because of this, the colloidal method Vela’s team used to make the materials takes less time and energy.
The colloidal synthesis technique, according to Vela’s team, gave them control over the nanocrystals’ size. Because it affects some materials’ optical properties, nanocrystal size is significant. According to Vela, scientists can alter the particle size to affect how well a material absorbs light. So, he said, “we might be able to make materials that are better for certain applications just by changing the size of the nanocrystals.”
Vela claims that the group’s initial objective was to create semiconducting alkaline-earth chalcogenide perovskites because of their potential application in solar technology. However, they required a deeper understanding of the basic chemistry of alkaline earth chalcogenides in order to achieve this goal. They decided to concentrate instead on these binary materials.
According to Vela, their study meets a need to advance scientists’ knowledge of earth-abundant, non-toxic photovoltaic, luminescent, and thermoelectric materials. “We hope that our developments with this project will eventually help in the synthesis of more complex nanomaterials, such as the alkaline-earth chalcogenide perovskites,” he said.
