Figure 2 (IMAGE) Kobe University Caption Top: Single-particle photoluminescence imaging of the halide exchange reaction using the flow reactor. The light emitted changed from red to green while the crystals maintained their morphology and light-emitting efficiencies. Below: Illustration of structural changes to the perovskite nanocrystal caused by the halide exchange reaction. The dark state is caused by insufficient electric charge for light generation, which resulted from the disruption of the crystal's inner structure (defects). Credit Tachikawa Takashi Usage Restrictions Please credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.