Chalcogenide is extruded in a diamond anvil at 1000-6000 times the atmospheric pressure to produce a solar panel material that is stable at room temperature.
Chalcogenide is a solar panel material with high conversion efficiency, and is cheaper and easier to produce, and has received much research attention in recent years.
A major obstacle to using this material for solar panels is that of its four atomic layouts (researchers call them “phases”), three have high conversion efficiencies, but are unstable at room temperature and tend to turn into a fourth, unusable phase that cannot convert solar energy into electricity.
A collaborative study by the U.S. Department of Energy’s SLAC National Accelerator Laboratory and Stanford University broke through this barrier: After the material was treated with a diamond anvil and squeezed at high temperatures, the material’s atomic layout was fixed in an efficient state and maintained, even when returned to room temperature and relatively humid air.
This is the first study to use pressure to control the stability of this material, and it does offer a lot of possibilities for applications,” said Yu Lin, a researcher at the Institute for Materials and Energy Studies (SIMES) at Stanford University. Now that we have found a high-quality way to treat this material, there is hope that it can be scaled up for commercial production and that other phases of chalcogenide can be treated in the same way.”
The material used to conduct the experiments in this study is halide chalcogenide, a compound of iodine, lead and cesium. One of the phases of this material, called “yellow,” is completely unconvertible to solar energy, according to the study. Previous studies have found that if high pressure is applied to it, it can be turned into the three atomic layouts needed for efficient solar cells. But the three layouts are still unstable, especially when exposed to moist air, and tend to change back to an ineffective atomic layout.
In this study, chalcogenide was squeezed inside a diamond anvil at 1,000 to 6,000 times the atmospheric pressure and heated to about 450 degrees Celsius. The researchers found that after this treatment, even if the pressure and temperature were restored to their natural state, the conversion rate remained highly efficient in relatively humid air for 10-30 days.
Lin Yu said that the pressure applied in their experiments was only about one-tenth of the pressure commonly used in the synthetic diamond industry. The research group will next apply the results from the experimental environment to industrial equipment to find ways to scale up the processing of this material.
The study was published Jan. 19 in the journal Nature Communications.
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