Light detection and emission are crucial for displays, medical and security scanners. Given the societal relevance, there is an emerging need for novel opto-electronic materials with higher conversion effi- ciency and lower production cost. Metal halide perovskites are promising high-performance semicon- ductors due to their strong absorption and emission in a broad spectral range and their ease of manu- facturing. So far, integration in opto-electronic devices was hampered by inherent stability issues such as the degradation from the optically active “black” phase into an inactive phase. Based on our recent proof-of-concept, we will explore a fundamentally new paradigm to stabilize the black phase under ambient conditions. This innovative concept exploits strain engineering, with thin films fixed to sub- strates and/or patterned at the nano- to micrometer scale. PERsist builds on the synergy between leading experts in high-end micro/spectroscopy & modelling of nanomaterials.