Extended Data Fig. 4: Thermal stability test for recycling solution.
Aqueous-based recycling solutions with or without H3PO2 stabilizer were placed at a temperature of 95 °C. The yellow-to-brown colour change indicates iodine formation in solution without H3PO2 stabilizer. The images were taken by moving solutions from the hotplate to a flat table for a clear background. The amount of perovskite powder precipitates varies in different images because the solution temperature may be different as cooling occurs while taking pictures.
