To understand exactly how perovskites behave under pressure, the scientists placed the crystals in a vice between two diamonds. As the diamonds were squeezed closer together, the perovskite samples changed color. These lab results indicate that perovskites can absorb high or low energy light waves, depending on the precise amount of pressure that is applied.
By tracking the positions of atoms upon compression using X-ray diffraction, we can explain exactly how the materials’ structure responds to pressure. Overall, this work shows that pressure is a tuning knob for improving the properties of perovskite absorbers in a predictable way.