10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Aerosol-assisted Synthesis of a Stable Perovskite Absorber Layer for Application in Photovoltaics
SHALINEE KAVADIYA, Joseph Strzalka, Robin Wheelus, Pratim Biswas, Washington University in St. Louis
Abstract Number: 395 Working Group: Materials Synthesis
Abstract Recent advances have enabled aerosol generation techniques to synthesize and deposit materials for various applications. These techniques are simple, scalable, and operate at atmospheric pressure. Moreover, they can be operated continuously and allow precise control of material properties (size, morphology, crystal structure, composition), which are the challenges for some of the solution-based techniques. Perovskite (CH3NH3PbI3) solar cells have received huge attention from the solar photovoltaic community in past few years because of their high efficiency and low-cost fabrication. However, their poor stability in ambient condition (mainly humidity) hinders their outdoor application. The presentation will discuss an aerosol-based technique, electrohydrodynamic atomization (i.e., electrospray), for fabrication of highly stable perovskite layer of perovskite solar cells under ambient humidity (30-50% relative humidity).
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 at room temperature. Both the precursors then react and form perovskite (CH3NH3PbI3). The key feature of this methodology is lowering the reaction rate between the two precursors by gradually supplying MAI in solid nanoparticle phase onto the PbI2 layer. The slow reaction leads to the formation of smooth and moisture-resistant perovskite film compared to the film fabricated by conventional solution-based techniques such as spin coating. The stability of the devices under the ambient condition is tested for 5.5 months. The cells fabricated using the electrospray retain 75% of the initial efficiency on average. The presentation will further discuss change in the structural properties of perovskite under heat treatment, and highly humid environment (≥ 80% relative humidity) investigated using in situ Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) at Synchrotron Facility, Advanced Photon Source at Argonne National Laboratory.
Reference: 1. Kavadiya et al., “Electrospray-assisted fabrication of efficient and highly stable perovskite solar cells at ambient conditions” Advanced Energy Materials, 1700210, 2017.