1. Mid-Infrared light emitters based on black phosphorus and its alloys Changhua Liu 2. Valley excitons and their many-body complexes Jiajie Pei 3. III-Nitride Optoexcitonics: Physics, Epitaxy, and Emerging Device Applications Yuanpeng Wu 4. Excitonic devices in 2D heterostructures Leonid Butov 5. Exciton diffusion in 2D van der Waals semiconductors Alexey Chernikov 6. Control of exciton transport/dynamics in 2D materials using surface acoustic waves Parag Deotare and Kanak Datta 7. 1. Excitons in Transition Metal Dichalcogenides sufei shi