Fig. 4
a Photograph of a green-to-red spectral conversion film with micro-structures on the top surface under green light illumination. Inset is the surface topography of the micro-structures. b Photograph of the semicylindrical roof domes arranged in the greenhouse facility. c The forward spectral irradiance of the spectral conversion film with surface micro-structures (red curve), the fluorescent film without surface micro-structures (green curve), the planar fluorophore-free film (black curve), and the fluorophore-free film with surface micro-structures (blue curve) under the emulated solar irradiance. d DLI inside all four domes. e–h Aboveground fresh weight (e) and dry weight (f), average leaf area (g) and SPAD values (h) of the lettuces at day 20 after transplantation. Republished with permission from [98]