## 3 Results and Discussion  
Figure 2 shows the UV-Vis-NIR transmission and diffuse reflectance spectra of the solar cells used as the tile units. In contrast to Si cells that do not transmit light all over the entire domain (300-1000 nm), DSSCs are partially transparent, similar with those reported in the literature [29]. In the case of the DSSC, the absorption of light radiation being modelled by the photoactive component of the solar cell, namely the dye, the UVA, and the visible and short wave NIR (750-1000 nm) ranges were analysed. Thus, the yellow tile absorbs in the range 370-457 nm, at the same time reducing the intensity of the blue radiation needed by chlorophyll a. The green tile is characterized by two broad absorptions at approximately 375-467 nm and 544-775 nm, and it also partially reduces the light intensity required for chlorophyll a and b. However, unlike the Si solar cell, DSSCs allow more light to pass through, avoiding the efficiency losses seen in opaque systems. Transmitting 5% of red and blue light, the green DSSC can provide the light intensity required for low-light-demanding crop plants. Furthermore, the diffuse reflectance spectra have highlighted a similar evolution, the dye also modelling the reflectivity of the tile. Before assembling into the tile and outdoor testing, all 14 DSSCs were characterized under a simulated solar radiation of AM1.5G and stored under dark conditions, open circuit, and at 22 \({}^{\circ}\)C. The J-V characteristics of the solar cells used in the construction of the tiles are presented in Figure 3 and are characterized by an efficiency of nearly 2.3% for the yellow DSSC, 1.89% for the green DSSC, and 11% for the commercial silicon solar cell. The climate of Timisoara, Romania is temperate continental with a monthly mean global solar irradiation in June of about 5.898 kWh/m\({}^{2}\)/day [30]. Figure 4 shows the solar irradiation under study for one day on the DSSCs' surface. It was observed that solar irradiance increased from 721 W/m\({}^{2}\) at 10:00 a.m. to 1000 W/m\({}^{2}\) at 1:00 p.m. After 2:45 p.m., the solar irradiation decreased smoothly until 4:15 p.m. at a value of 794 W/m\({}^{2}\). From 4:30 p.m., solar irradiance decreased drastically until 6:00 p.m. at a value of 40 W/m\({}^{2}\). Figure 2: UV-Vis- Short Wave NIR (**a**) transmission and (**b**) diffuse reflectance spectra of the solar cells used as the tile units. Special attention was given to the maximum air temperature of 44.9 \(\pm\) 0.9 \({}^{\circ}\)C recorded during the measurements between 2:00-3:00 p.m. Figure 5 illustrates the evolution of the temperature transmitted through each tile. In the case of the Si tile, the transmitted temperature varies between 69.2 and 70.9 \({}^{\circ}\)C. The rise of 20 \({}^{\circ}\)C compared to the air temperature is caused by the increase in absorbance, especially of the infrared radiation. Thus, the heat accumulation in the Si tile is responsible for the increased cell surface temperature [31]. Due to the high and broad wavelength reflectivity, a more moderate heat transmitted by the yellow tile was measured, with the maximum temperature varying by only approximately 12 \({}^{\circ}\)C above the air temperature. Surprisingly, but also expectedly, the maximum temperature transmitted by the green tile was below the air temperature, namely 41.85 \(\pm\) 1.05 \({}^{\circ}\)C. The average temperatures between 2:00 and 3:00 p.m. show a decrease in temperature of approximately 3 \({}^{\circ}\)C compared to the ambient temperature. Thus, as can be observed, the DSSC based on green dye acts as a filter, preventing heating through absorption of the near-infrared light in the range of 700-775 nm (Figure 2) and converting it into electrical energy along with significant reflectance after the wavelength of 775 nm. In terms of diminishing the cost of crop production by reducing the energy consumption from conventional sources, the evolution of \(P_{max}\) for all three tiles were monitored during a hot summer day (Figure 6).