In the present work a first approach survey on the structure, materials and characteristics of PSCs is provided. Consequently, especial attention is paid here to the issue of performance stabilization, which currently centers the most of attention among researchers in the field. Moreover, regarding the mechanisms behind the device operation, a discussion on the anomalous phenomenon of hysteresis in the current density-voltage (J V) curve is presented, as well as its relation with other behaviors such as the low frequency capacitance [14] and the slow electrical material response under light irradiation [15]. Note that the manuscript is also intended to guide the readers throughout a selection of recent high impact original papers and review articles, as well as provide them with handy experimental data.
 

II.      STRUCTURE OF PSCs

 
The PSCs structure basically consists in a light harvesting perovskite sandwiched between electrons and holes selective contacts. Several materials has been reported [16], however probably the most successful and extensively studied arrangement is that showed in Figure 2 where on top of the fluorine-doped tin oxide (FTO)/glass substrate the TiO2 layer is grown, then the CH3NH3PbI3 perovskite and later the spiro-OMeTAD. The metallic electrodes are often made of gold in order to achieve better connections with the load (RLoad), despite other non-precious metals has been also explored [17]. Thus, in this regular structure the light crosses the substrate throughout the glass and the transparent conducting oxide (TCO), then first through the electron-transport material (ETM) to be absorbed at the perovskite, the hole-transport material (HTM) being afterward in the light path.
In some devices, variations in the regular structure have been considered as the ETM (or HTM) free PSCs and the HTM free PSCs. Particularly pointed by Meng et al. [18], another important configuration is the inverted, where in the same light path direction the sequence of layers is glass/TCO/HTM/perovskite/ETM/counter-electrode [19]. In the review by Zhou et al. [20] the characteristics of all of these architectures are systematically analyzed.