(604a) Highly Stable Perovskite Solar Cells Fabricated Using Aerosol-Based Technique
The key features of the electrospray-based deposition are: 1) precisely controlled reaction between the two precursors, by gradually supplying MAI nanoparticles onto the PbI2 layer and 2) intermediate phase formation during the electrospray of MAI nanoparticles. Both of these characteristics lead to the formation of ultra-smooth and moisture-resistant perovskite film. Smoothness of the film is examined by atomic force microscopy (root mean square roughness is 31 nm for electrosprayed perovskite film and 58.9 nm for spin coated film over a large area of 50 Î¼m Ã 50 Î¼m) and moisture-resistance is examined by contact angle measurement (66.09° for electrospray film and 33.01° for spin coated sample). The intermediate phase formation is characterized by X-ray diffraction (XRD) and change in the XRD pattern is observed during annealing. 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. Material stability is also investigated by monitoring the amount of PbI2 generating from the perovskite degradation and is correlated to the device stability. Electrospray also provides precise control over the material required to form the perovskite layer, reducing material loss. Therefore, electrospray technique is promising for the large-scale fabrication of stable and efficient perovskite solar cells under ambient condition. Details of the electrospray-assisted system and highly stably perovskite formation using this technique will be presented.
Kavadiya, S. et al., Advanced Energy Materials, 10.1002/aenm.201700210