Wiley | Advanced Materials Follow Coordination Compensation Stabilization of Monodentate‐Ligand Copper‐Iodide Hybrids for Efficient Light‐Emitting Diodes With Record‐High External Quantum Efficiency Above 20% https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.73745?af=R advanced.onlinelibrary.wiley.com