**Author details**

devices, the degradation process should be clearly understood where there are few reports about the effects of O2 on perovskite films. According to the study about the degradation mechanism of the perovskite under water [109], it is shown that the hydrolysis reaction of

*Photo‐stability:* The mesoporous TiO2 layer in the device is preferred in order to easily transport photo‐generated electrons. On the other hand, TiO2 is inherently sensitive to ultraviolet light, which may cause degradation in PSCs. The instability of encapsulated and nonencapsulated perovskite devices was investigated through considering the device efficiency by Snaith et al. [110], and it is showed that the degradation of the first‐type device occurs faster than that of the second type. Nevertheless, the first device has given a more stable condition in the lack of UV light. In order to overcome this photo‐instability due to the TiO2 layer, the respective authors suggest some methods such as pacifying the trap states, replacing the TiO2 layer with other materials, and avoiding UV light from the TiO2 layer. For example, stability at over 1000 hours at 40°C is accomplished when mesoporous Al2O3 is used instead of TiO2 layer in the PSC device. Nonetheless, the PCE was decreased to around by half of its first value after the first

*Thermal stability:* Thermal stability is an issue regarding both perovskite material and in HTM layer. The intrinsic thermal instability of a perovskite material was reported in the literature [111], and it is showed that even though the film was maintained in an inert condition, the degradation of perovskite is seen at 85°C. It means that the SCs may not be used properly in

Perovskite has been the most initiative and promising material in terms of energy harvesting among organic, inorganic, and organic‐inorganic SCs [8]. In case the difficulties, which are mainly about stability, are overcome, the humanity would face to a new and affordable solar energy harvester for future use. Therefore, the novelties in PSC technology attract a large amount of attention in our recent world due to its significance on its effectiveness on electricity

The main prospects for the future cover the strategies in terms of reducing the band gap, enhancing the light absorption capacity, and improving the conversion efficiency. In addition, exposing the charge transport properties and improving interfacial engineering methods in device fabrication are important. Especially, the chemistry work on chemical composition has great value. Hence, the lion's share for future work should be explaining the photo‐physical

Unfortunately, the present information obtained on "how PSCs operate?" is rather insufficient at least for now. Because the complete working principle is not well explained [18, 19]. Therefore, deriving novel clues on (1) light absorption, (2) charge separation, (3) charge transport, and (4) charge collection are needed during research since these four key issues are

general SC parameters to identify the principal working of solar conversion process.

200 hours. A continuing reduction is also observed in both Voc and FF values.

cases where the SC temperature exceeds this temperature level.

mechanism of solid‐state SCs with respect to different chemicals.

production from free and abundant sunlight.

**6. Summary**

294 Nanostructured Solar Cells

CH3NH3PbI3 arises under humid condition.

Serafettin Demic1\*, Ahmet Nuri Ozcivan2 , Mustafa Can3 , Cebrail Ozbek1,2 and Merve Karakaya4

\*Address all correspondence to: serafettin.demic@gmail.com

1 Department of Materials Science and Engineering, Izmir Katip Celebi University, Izmir, Turkey

2 Department of Electrical and Electronics Engineering, Izmir Katip Celebi University, Izmir, Turkey

3 Department of Engineering Sciences, Izmir Katip Celebi University, Izmir, Turkey

4 Depertment of Materials Science and Engineering, Izmir Institute of Technology, Izmir, Turkey
