New and emerging photovoltaics technologies such as single-junction perovskites and 4 and 2 terminal tandem structures based on perovskite in combination with perovskite, silicon and CIGS as sub-cells demand more advanced characterization methods for understanding degradation mechanisms occurring therein and subsequently contributing to improvement of their properties. Therefore, here, degradation in perovskites and perovskites on silicon tandem were investigated through the use of advanced optical and electrical characterization methods. Methods of Dark Lock-In Thermography (DLIT), Electroluminescence (EL) and Photoluminescence (PL) were applied beside power output (IV) and external quantum efficiency (EQE) measurements. These optical and electrical measurement methods are applied effectively in quality control and development support and are important characterization tools in industry and research. EL, PL and DLIT imaging are non-destructive measurement techniques. These types of optical measurement provide fast, real-time and high resolution images and will give a two-dimensional distribution of the characteristic features of PV cells and allow the investigation of cracks, defects, shunts and stacking faults in the cells. IV- and EQE-measurements help to get a complete picture of the power conversion efficiency of solar cells. IV-measurements give the current generated by the cell under simulated solar irradiation conditions and EQE-measurements provide a quantification of the generated current at each wavelength.