So the purpose of this work is
Before annealing, cf. Fig. 4, the 50/25 sample shows both crystalline ZnO and a crystalline intermediate species (Zn3(OH)4(NO3)2). The presence of this impurity could explain the broad Eg shift (0.14 eV). In the case of the 50/10, it is less clear, as only ZnO is observed, however the peaks are of lower intensity, probably meaning that a lower crystallized ZnO has been deposited, and niche also might explain the Eg (0.06 eV) observed.