## 3 Results and Discussion
Deconvolution (**b**) of the normalized luminescence spectrum of MPC based on Tb\({}^{3+}\) ions and P1. The squares are raw data from the original spectrum. The red curve is cumulative as the sum of the individual pale-painted peaks obtained by deconvolution using Equation (2). The calculation is performed in OriginPro [34]. It is known that excimers are \"traps\" [35] for exciting light, and FRET is ineffective in such systems. Therefore, in PMMA films containing the homopolymer PVK and Tb\({}^{3+}\), the Tb\({}^{3+}\) luminescence intensity is \(\sim\)5 rel. units [36]. Figure 7c explains in general terms the probable channel of energy dissipation through the excimer emission of VK units, which does not allow for the emission of Tb\({}^{3+}\) ions in the [Tb\({}^{3+}\)/PVK] system. The luminescence spectra of metal\(-\)polymer complexes in PMMA film were deconvolved to consider the contributions of luminescence bands of different luminescent systems: individual VK units, their excimers, and Tb\({}^{3+}\) in MPC. By deconvolving the emission spectra (Figure 6), an asymmetric double sigmoidal _Asym2 Sig_ function [34] was used to determine the full width contribution at half-maximum (FWHM):  
\[y=y_{0}+A\frac{1}{1+e^{-\frac{x-x_{0}-y_{1}/2}{w_{2}}}}\left(1-\frac{1}{1+e^{ -\frac{x-x_{0}-y_{1}/2}{w_{3}}}}\right) \tag{1}\]  
where \(y_{0}\) is the displacement, \(x_{\text{c}}\) is the center of gravity, \(A\) is the amplitude, \(w_{1}\) is the full width of the half maximum, \(w_{2}\) is the dispersion of the low-energy side, and \(w_{3}\) is the dispersion of the high-energy side. The lower bounds were for \(w_{1}>0.0\), \(w_{2}>0.0\), and \(w_{3}>0.0\) when approximated. Each spectrum was processed using the sum of _Asym2 Sig_:  
\[I_{lum}=\sum_{k=0}^{n}Asym2 Sig_{k}+B \tag{2}\]  
Figure 7: The structural scheme for the model of the Tb\({}^{3+}\) complex proposed with poly(VT-co-VT) (**a**,**b**). Probable mechanism of excimer trapping in PVK (**c**). where \(n\) is the number of approximated peaks in the absorption band, and \(B\) is the total background for all _Asym2 Sigg_, standing for the sum of \(y_{0K}\). The obtained values are given in Figure S1 (see Electronic Support Materials' file--ESM). In Figure 6b, we present the deconvolution for the film in which poly(VT-_co_-VK) with 9 mol. % of VK units was used (Figure S1 in ESM). Taking into account the above, it is possible to estimate the contribution, %\(I_{\text{E}^{*}}\), in the photoluminescence spectrum for the MPC in the PMMA matrix (Figure 6) using the cumulative area under the curves of the peaks corresponding to high- and low-energy excirmers [VK\(\cdots\)VK]* with centers of gravity, \(x_{\text{c}}\), at ca. 364, 388, 420, and 460 nm (Figure 6; Figure S1 and Table S1, see in ESM). The photoluminescence peak for VK units had the value of \(x_{\text{c}}\) in the region of 352-357 nm. The results indicate that augmenting the excimer luminescence contribution, calculated as the ratio of the %\(I_{\text{E}^{*}}\) value to the value of the VK unit luminescence contribution, %\(I_{\text{M}}\), intensified with the rise in VK unit content within the copolymer (Figure 8, curves 5 and 6). The value of %\(I_{\text{E}^{*}}\)/%\(I_{\text{M}}\) characterized the electronic excitation energy transfer (EET) rate in photoprocesses in PMMA films containing the MPC based on Tb\({}^{3+}\) and poly(VT-_co_-VK) (Table S1 in ESM). The increase in the latter value arose due to the effective overlap of the VK-VK units in an excited state. The Tb\({}^{3+}\) luminescence contribution, %\(I_{\text{TD(II)}}\), decreased symbatically with the decreasing %\(I_{\text{M}}\) value, which allowed us to conclude that the electronic excitation energy was transferred from the excited structural units of VK to the lanthanide ion (Figure 8, curves 1 and 2).