Halide perovskite semiconductors are the most exciting new materials for solar cells, LEDs, optical computing and neural networks, but their widespread commercialization is still limited by their intrinsic instability. This is a result of the mobile ions inherent to the ionic semiconductor. Here we will develop a novel way to make the ions “sing” in response to light, revealing information about processes normally only accessible with electrical measurements. This purely optical method provides additional spectral information, simple spatial and depth mapping as well as contact free analysis which will help accelerate commercialization and thus the energy transition.