## 3 Results and Discussion
Broadened signals of triazole ring protons were observed in the region of 7.50-8.15 ppm (c, d), while strongly broadened signals of carbazole ring protons resonated in the region of 7.50-8.15 ppm (g). Figure 3: TGA (a) and DSC (b) curves of poly(VT-_co_-VK) copolymers (for example P3). Figure 2: FT-IR spectra of P1–P3 poly(VT-_co_-VK) copolymers. Figure 5 shows the absorption and luminescence spectra of P1-P3 poly(VT-\(\alpha\)-VK) copolymers, depending on the content of VK units in DMF. The content of VK units in the copolymer was in good agreement with the absorption of these units in the region of 320-360 nm (Figure 5a). In the luminescence spectra in solution, individual VK monomer units appeared at about 350 nm. It is known [33] that the luminescence spectrum of polyvinylcarbazole (PVK) is mainly represented by excimer luminescence, the short-wavelength band (365-370 nm) that belongs to excimers formed due to the interaction of partially overlapping VK groups, and the long-wavelength (400-420 nm) band belongs to excimers formed by the interaction of completely overlapping VK groups. The band with a maximum at 350 nm, corresponding to the luminescence of individual VK units, practically disappeared for the homopolymer. In the case of normalization of the emission spectra at 360 nm in the luminescence region of high-energy excimers, it is clearly seen (Figure 5b) that already in solution, with an increase in the local concentration of VK units due to an increase in their molar content in the polymer chain, the contribution of monomer units decreased and the contribution of luminescence increased low-energy excimers in the region of 400-420 nm. Figure 6a shows the photoluminescence spectra of the obtained MPCs based on Tb\({}^{3+}\) ions and synthesized 1-vinyl-1,2,4-triazole code copolymers with a variable content of \(N\)-vinylcarbazole units with hole conductivity (9, 16, and 37 mol.%) in the matrix PMMA. In  
Figure 4: 1H NMR spectra of P1–P3 poly(VT-\(\alpha\)-VK) copolymers. Figure 5: Absorption (**a**) and normalized emission (**b**) spectra of poly(VT-\(\alpha\)-VK) copolymers in DMF by varying the VK content: 9 mol. % (P1), 16 mol. % (P2), and 37 mol. % (P3). Emission spectra are normalized at 360 nm. fluorescent mode (the emission measurement time window starts from zero), for all poly(VT-_co_-VK) compositions, two luminescence regions were observed: a short-wavelength one with a wideband from 340 to 450 nm and a long-wavelength one consisting of three distinct bands with a maxima at 489, 544, and 587 nm. An analysis of the photoluminescence spectra strongly suggests that the emission bands present in the long-wavelength region could be associated with the corresponding \({}^{5}\)D\({}_{4-}\)\({}^{7}\)F\({}_{6}\), \({}^{5}\)D\({}_{4-}\)\({}^{7}\)F\({}_{5}\), \(n\)\({}^{5}\)D\({}_{4-}\)\({}^{7}\)F\({}_{4}\) transitions of the electrons of the Tb\({}^{3+}\) ion (in the notation of the Russell\(-\)Saunders terms) [14; 15]. At the same time, photoluminescence of the vinylcarbazole component was observed in the short-wavelength region [33]. For individual Tb\({}^{3+}\) ions dispersed in a PMMA matrix at the appropriate concentration, their luminescence signal was not observed under similar measurement conditions, thus it can be said that the polymeric ligand poly(VT-_co_-VK) sensitized the luminescence of the lanthanide ion, playing the role of a molecular antenna. Moreover, in this case, the energy of electronic excitation was transferred from the units of the VK that absorbed exciting light to Tb\({}^{3+}\) ions by a induction-resonance dipole\(-\)dipole mechanism--the Forster resonant energy transfer (FRET)--up to 6 nm [14]. Figure 7a,b shows the possible model explaining the metal\(-\)polymeric complex formation locally. Figure 6: Normalized photoluminescence spectra (**a**) of MPC based on Tb\({}^{3+}\) ions and poly(VT-_co_-VK) copolymers with 9 (P1), 16 (P2), and 37 mol. % (P3) of VK units in a photoinert PMMA matrix. Excitation 300 nm. Emission spectra are normalized at ca. 365 nm.