Light-emitting quantum dot films, quantum dot lighting devices, and quantum dot-based backlight units are provided. Related compositions, components, and methods are also described. Improved quantum dot encapsulation and matrix materials are provided. Quantum dot films with protective barriers are described. High-efficiency, high brightness, and high-color purity quantum dot-based lighting devices are also included, as well as methods for improving efficiency and optical characteristics in quantum dot-based lighting devices.