Review on Spectrally Regulating Agricultural Greenhouse Films

Abstract

Climate change and increasing heat stress in greenhouses are driving the demand for improved regulation of the greenhouse light and thermal environments. Spectral‐regulating agricultural greenhouse films can regulate the transmission, reflection, and conversion of solar radiation while enhancing mid‐infrared thermal emission, thereby contributing to the regulation of the internal greenhouse temperature. This review summarizes the fundamental working mechanisms of these films, with emphasis on photoconversion, wavelength‐selective light transmission, and greenhouse energy balance. According to their material characteristics, spectral‐regulating greenhouse films are categorized into fluorescent‐dye‐based, rare‐earth‐complex‐based, and quantum‐dot‐based systems, with particular attention to their light‐conversion behavior, optical properties, stability, and agricultural applicability. From the perspective of structural design, layered structures, micro‐/nanophotonic structures, and multifunctional composite or system‐level structures are discussed in relation to the coordinated regulation of photosynthetically active radiation, near‐infrared radiation, and thermal emission. Practical considerations, including long‐term durability, large‐area fabrication, cost, crop performance, and adaptability to different climatic conditions, are further examined. Finally, future research directions are discussed toward the development of high‐performance, practically applicable, and sustainable spectral‐regulating greenhouse films for protected agriculture.