During my μ-PCD measurements on both a single crystal and polycrystalline sample of FAPbI3 using a 355 nm YAG laser, I observed an unexpected phenomenon. As I increased the power excitation from 0.1mW to 2mW, I noticed that the lifetime decay became slower instead of faster. Specifically, the lifetime decay increased for the polycrystalline sample, whereas it decreased for the single crystal sample. This contrasts with the anticipated behavior of decreasing lifetime decay for both samples. I am curious to understand the underlying reasons behind this discrepancy.