## 3 Results and Discussion  
The photoluminescence of the polymeric materials was found similar to that of the bio-molecules in solution [15] under UV irradiation (Figure 1). Figure 2a shows the emission spectra of the R-PE/PVA dominated by the R-PE characteristic emission (Figure S2 in Supplementary Materials) with two components centered around 577 nm and 663 nm [15; 30], which are independent of the excitation wavelength (Figures S3 and S4 in Supplementary Materials). The presence of two distinct dye-related components in the emission spectra points out the formation of dye aggregates [15; 31] and the increase in the relative intensity of the low-energy component (663 nm), suggests the presence of \(J\)-dimers [15; 32]. Both in R-PE/PVA and R-PE/alginate, the high-wavelength peak is red-shifted from 650 nm before incorporation (Figure 3a) to 665 and 663 nm after incorporation into PVA and sodium alginate (Figures S3 and S4 in Supplementary Materials), respectively, suggesting the formation of protein agglomerates in the solid-state. The emission spectra of C-PC in H\({}_{2}\)O (Figure 3a and Figure S5 in Supplementary Materials) for excitation wavelengths between 360 and 590 nm are formed by a component between 600 and 750 nm, with a peak at 674 nm, and a band with smaller relative intensity within 400 and 550 nm (Figure S5 in Supplementary Materials) [5; 31]. After incorporation into PVA, the emission remains dominated by C-PC characteristic emission as given by the peak around 665 nm (Figure 2a) [31], revealing an increase in the relative intensity of the component at shorter wavelengths (Figure S6 in Supplementary Materials). The FX in solution and incorporated in thin films of PVA reveal emission when excited in the UV range (Figure 1c). The emission spectrum of the FX in ethanol shows an emission band between 650 and 750 nm, with a peak at 675 nm, and a component with lower relative intensity between 500 and 650 nm (Figure 3a and Figure S7 in Supplementary Materials). The spectra are identical for excitation wavelengths between 350 and 600 nm (Figure S7 in Supplementary Materials). After incorporation into PVA, the emission spectra show a main band peaking around 675 nm (Figure 2a and Figure S8 in Supplementary Materials) and an increase in the relative intensity of the component at shorter wavelengths (Figure S9 in Supplementary Materials). Figure 1: Photographs of (**a**), from left to right, R-PE/PVA and R-PE/alginate, (**b**) C-PC/PVA, and (**c**) FX/PVA under white light (**top**) and UV irradiation at 365 nm (**bottom**). Scale bars: 10\({}^{-2}\) m.  
intensity of the band at shorter wavelengths (Figure S8 in Supplementary Materials). The excitation spectra revealed the same components both for FX in ethanol and incorporated into PVA, as presented in Figure 2b, Figures S7 and S8 in Supplementary Materials. These results show that the tested molecules preserve their emission and excitation features after incorporation into solid matrices and that the emission and excitation spectral regions are compatible with c-Si PV cells absorption and the available solar photons on earth, respectively (Figure 2). We notice that FX is mainly excited in the UV spectral region ensuring a larger Stokes shift suggesting that self-absorption could be minimized. The ability to down-shift the UV radiation arises from the intrinsic absorption of the bio-molecules in solution, as illustrated in Figure 3b. These absorption features are kept after incorporation into the host. In particular, the excitation spectra of R-PE after incorporation into PVA or sodium alginate also resemble that of the biomolecules (Figure 3b, Figures S3 and S4 in Supplementary Materials), being dominated by the excited states of the R-PE in the visible spectral range, revealing the presence of components in the UV/blue (320-440 nm) spectral region attributed to the chromophores' singlet states [15].