Researchers have developed light-emitting diodes (LEDs) using van der Waals heterostructures with precise bandstructure engineering. By stacking atomic layers of graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDCs), they created quantum well (QW) structures that exhibit high quantum efficiency and tunable emission. The LEDs demonstrate extrinsic quantum efficiency of nearly 10% and can emit light across a wide range of frequencies by selecting different TMDCs. The heterostructures are flexible and semi-transparent, enabling applications in flexible electronics. The technology allows for the creation of various devices, including LEDs, lasers, and indirect excitonic devices, by combining different 2D materials. The study shows that the quantum efficiency can be significantly improved by using multiple QWs, achieving up to 8.4% efficiency. The devices also exhibit strong electroluminescence and are robust, with performance remaining stable over time. The research highlights the potential of van der Waals heterostructures for advanced optoelectronic applications, with quantum efficiencies comparable to modern organic light-emitting diodes (OLEDs). The work is supported by various funding bodies and demonstrates the feasibility of scalable production through advances in CVD growth techniques.Researchers have developed light-emitting diodes (LEDs) using van der Waals heterostructures with precise bandstructure engineering. By stacking atomic layers of graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDCs), they created quantum well (QW) structures that exhibit high quantum efficiency and tunable emission. The LEDs demonstrate extrinsic quantum efficiency of nearly 10% and can emit light across a wide range of frequencies by selecting different TMDCs. The heterostructures are flexible and semi-transparent, enabling applications in flexible electronics. The technology allows for the creation of various devices, including LEDs, lasers, and indirect excitonic devices, by combining different 2D materials. The study shows that the quantum efficiency can be significantly improved by using multiple QWs, achieving up to 8.4% efficiency. The devices also exhibit strong electroluminescence and are robust, with performance remaining stable over time. The research highlights the potential of van der Waals heterostructures for advanced optoelectronic applications, with quantum efficiencies comparable to modern organic light-emitting diodes (OLEDs). The work is supported by various funding bodies and demonstrates the feasibility of scalable production through advances in CVD growth techniques.