## 3 Results and Discussion
The biosynthesized samples exhibited an increased share and size of the pores in comparison to the reference powder, which were responsible for the increased specific area (80 and 140 m\({}^{2}\)/g for G1 and G2, respectively). The average pore size of G0 was 9.5 nm, while the G1 and G2 powders had pores size 16 nm and 17 nm, respectively. The IR spectrum of the **MA** extract had a band, located at 1065 cm\({}^{-1}\), which could be assigned to the C-O bond from biomolecules [44] (Figure 7). The band at 1634 cm\({}^{-1}\) belongs to an aromatic ring [45], while the one at 1573 cm\({}^{-3}\) corresponds to the N-H bending vibration of amine or amide groups, which could be due to the presence of different phytochemical  
Figure 5: EDX spectrum of the plant-mediated G2 powder and the reference powder (inset); the arrow indicates Au originating from conductive material. Figure 6: Pore size distribution curves of plant-mediated ZnO samples. The band at 2960 cm\({}^{-1}\) corresponds to asymmetric C-H stretching, while the bands at 2924 cm\({}^{-1}\) and 2852 cm\({}^{-1}\) correspond to saturated sp\({}^{3}\) carbon [46]. In the IR spectra of the particles obtained by us, a difference in the intensity of the bands within the range of 400-1700 cm\({}^{-1}\) was observed, as it decreased with the increase in the **MA** extract quantity. All spectra showed broad bands in the region of 466 cm\({}^{-1}\), which is characteristic for the formation of the Zn-O bond. At 948 and 707 cm\({}^{-1}\), peaks could be attributed to CH\({}_{3}\) bending modes, while the band at 1047 cm\({}^{-1}\) corresponds to the carbonate group [47]. The strong peaks at 1402 and 1500 cm\({}^{-1}\) belong to carboxylate stretching modes [48]. The shoulder at 1636 cm\({}^{-1}\) derived from the **MA** extract was also observed in the spectra of the G1 and G2 samples [46], while the one at 1384 cm\({}^{-1}\) corresponds to the C-H group in an aldehyde compound [36]. EPR spectroscopy is an effective technique to identify unpaired electrons so that the surface paramagnetic defects, radicals, cations or clusters are easily detected through EPR signals. The spectrum of the G1 sample consisted of two signals, S1 and S2 (Figure 8). The S1 signal was recorded at g = 1.9534, which is attributed to ionized oxygen vacancy defects (V\({}_{0}\)\({}^{+}\)) [49]. The second signal was detected at a g-value of 1.997 (S2). According to literature data, the signal with a g-factor close to the free electron 2.0023 in ZnO refers to singly ionized oxygen vacancies (V\({}_{0}\)\({}^{+}\)) defects [50,51]. Other researchers detected a similar peak with g = 2.003, attributed to Zn vacancy [52] or nonaxial negatively charged Zn vacancy complexes [53]. In the spectrum of the G2 sample, the S1 signal disappeared, while a new resonance signal was detected at 322 mT with g = 2.04 (S3). [PERSON] et al. [51] observed a similar signal in N-implanted ZnO at 324 mT  
Figure 8: EPR spectra of plant-mediated ZnO powders. Figure 7: Infrared spectra of plant-mediated ZnO samples. (g = 2.0025), which was attributed to V\({}_{0}\)-V\({}_{\mathrm{Zn}}\) clusters. Other researchers recorded a signal at g = 2.03, associated with negatively charged zinc vacancy-interstitial zinc (V\({}^{-}\)Zn\({}_{\mathrm{n}}\)\({}^{\mathrm{i}}\)) complexes [53]. In order to investigate the type of atomic-scale defects in the samples, the PL spectra were measured at room temperature using a 325 nm excitation source. Figure 9 illustrates these results and as one can see, the spectra were very similar, with some intensity variations. More specifically, each spectrum exhibited a low-intensity UV near band-edge (NBE) emission at 375 nm and several intensive bands in the visible region. It is well known that the intensity ratio of the NBE to the defect-related visible emission could be taken as an indication of the crystalline quality of the sample [54]. As can be seen, the relatively strong intensity of the visible emission suggests a high degree of defect concentration in the samples.