The aim of this project is to go beyond standard material characterization by studying the electronic properties of devices during operation. Leveraging the unique platform developed by our group at INSP, which combines Raman, infrared, and visible spectroscopy with multi-source X-ray photoemission (XPS) across a broad energy range (from meV to 5 keV), and offering precise control of temperature and bias, we will explore the energy landscape of nanocrystal-based LEDs. These devices have a vertical geometry typically incompatible with the low escape depth of standard photoelectron spectroscopy. However, the hard X-ray capability of our setup, combined with the redesigned device architecture incorporating 2D materials, will allow us to probe the active layer under operando conditions.