Persistent phosphors are a special type of luminescent materials that have the distinctive ability to continue emitting light long after excitation has ceased. While they are commonly used indoors for safety signage and glow-in-the-dark gadgets, we cannot yet rely on their light output for outdoor applications. This is because the changing environmental conditions (illumination and temperature) have a strong impact on both the charging during the day and the release of photons during the night. Being able to understand and model the underlying mechanisms would give us the ability to improve existing phosphors and develop new ones that are tailored to perform well under all weather conditions, making outdoor applications tangible. Incorporating such a material into road markings would eliminate the need for streetlights in many locations (e.g. bike paths, park roads), counteracting the ever-growing problem of light pollution and the related yet avoidable energy consumption. The proposed project approaches this innovational goal from multiple fronts, with an iterative feedback-loop: we evaluate phosphors in terms of their thermal and optical behavior and then feed the results into the model to find new promising compositions. This will help us to increase the overall storage capacity and ensure a more uniform light output from dusk to dawn, which will be tested during an extended field test.