## 1 Introduction  
Sustainable agriculture has an important role to play in the continuous provision of food to the population. Consequently, for farmers, the problem of increasing the productivity of agricultural crops is always in the forefront of their minds. Everyone knows that for good harvest production, it is necessary to provide the most favorable conditions: lighting, watering, nutrition, and temperature mode. The intensification of agriculture implies a transition to the year-round cultivation of plants, which is effectively realized in modern greenhouses. The design features of greenhouses allow for optimized growth conditions and increased crop yields while reducing costs [1; 2; 3]. The protective environment of greenhouse allows the growth of thermophilic plant species ubiquitously, as well as the planting of seeds and harvest of crops several times a year. The most important feature of greenhouses is their maximum transmittance of sunlight to the plants. However, even this property is not always sufficient to achieve the best result, due to sunlight deficit in temperate regions. Currently, artificial lighting is used to solve the problem of the lack of sunlight, but this leads to an increase in energy consumption [4; 5; 6]. Photoconversion coatings of greenhouse glass are an example of smart and efficient production technologies, which reduce costs and increase yields. Normally, agricultural photoconversion covers transform the light, which is least absorbed by plants, into photosynthetically active radiation (PAR). It is assumed that the potential economic effect of using photoconversion coatings can be achieved by reducing the cost of electricity, and of the purchase and maintenance of equipment for artificial lighting, as well as increasing the productivity of crops. Light quantity and quality affect photosynthesis efficiency, plant growth and metabolism [7; 8; 9], and farmers should ensure that plants have optimal lighting. PAR is a light with wavelengths 400-700 nm. This waveband at sunny weather can contain approximately 25% of the sunlight photons, which leaves a lot of potential for the application of photoconversion technologies in the greenhouse. In the 19 th century, the research of [PERSON] and [PERSON] demonstrated that red and blue photons are most able to maximize the productivity of plant photosynthesis, and this was later confirmed by [PERSON] [10]. Despite all the advantages of red illumination for photosynthesis, blue, green, yellow, and far-red lights additionally intensify the photosynthesis, optimize plant biochemistry, and improve crop quality [11; 12; 13; 14; 15; 16; 17; 18]. A wide range of devices are being developed that are made with luminescent materials (metal complexes, semiconductors, nanoparticles, fluorescent proteins, organic dyes), including some for agriculture [19; 20; 21; 22]. The main limitations for the agricultural application of photoconversion devices is the inability to manufacture ideal covers, which have a light transmittance and harvesting performance in given parts of the solar spectrum, high quantum yield and good stability when exposed to rain, high intensity light and extreme temperatures.. Unfortunately, almost all photoconversion coatings produced so far have critical problems. The organic fluorophores incorporated in coatings rapidly photobleach, with a decrease in the quantum yield of photoconversion. The relatively stable rare-earth elements-based fluorophores have a low yield of luminescence [23; 24; 25; 26; 27]. The illumination of nanoparticles with plasmon or exciton emissions (cadmium selenide, zinc sulfide, etc.) [28] leads to the generation of reactive oxygen species, which cause damage to phosphors. Moreover, this type of particles is hardly integrated in polymers. An important goal of modern research is the creation of photoconversion coatings, which will include durable phosphors with optimal photoabsorbing and emitting properties [29; 22].