In addition to achieving higher efficiencies, it is essential to improve the stability of perovskite solar cells (PSCs) for their commercialization. A majority of the synthesis and evaluation studies are performed under controlled environments and use additives or encapsulation methods to enhance their stability. We demonstrate a simple, scalable and novel aerosol-based technique, electro-hydro atomization, to fabricate highly stable PSCs under ambient conditions (room temperature, humidity and atmosphere), without use of any additives or encapsulation. A two-step deposition method is used to form the perovskite layer, where PbI2 is spin coated and CH3NH3I (MAI) is electro-sprayed on the PbI2 layer. The key feature is controlling the reaction between the two precursors precisely, by gradually supplying MAI nanoparticles onto the PbI2 layer. The controlled reactivity leads to the formation of ultra-smooth and moisture-resistant perovskite film. The cells fabricated using the electrospray are more efficient (up to 12%) and highly stable (up to 5.5 months) under ambient condition than the cells prepared using a conventional spin coating method. Additionally, the electrospray-deposited film exhibits self-healing behavior when exposed to moisture. Another interesting phenomenon is the change in the crystal structure of the perovskite during annealing of the film, which is assumed to promote the smoothness. The electrospray technique can be scaled-up for larger-scale fabrication and precisely controls the material required for deposition, thus reducing the loss that occurs in the solution-based techniques. Details of the electrospray-assisted formation of highly stable perovskite films and their crystal chemistry will be presented.

Aerosol routes to fabricate highly stable perovskite solar cells under ambient conditions

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.