AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Aerosol-assisted Fabrication of Stable Perovskite Solar Cells at Ambient Conditions
SHALINEE KAVADIYA, Su Huang, Pratim Biswas, Washington University in St. Louis
Abstract Number: 156 Working Group: Nanoparticles and Materials Synthesis
Abstract Perovskite solar cells have shown to be a promising photovoltaic technology in the market, due to the rapid rise in their efficiency and low processing costs. Despite their high efficiency, the instability of perovskite material is a serious obstacle to their commercialization. Perovskites readily decompose in the presence of moisture. Thus, most of the studies are performed in a controlled humidity environment. Recent studies have focused on improving their stability by encapsulating the cell or incorporating a hydrophobic material into the perovskite layer. However, solar cell fabrication still occurs in very low humidity conditions. Our previous work reported a method to improve the stability at ambient condition by adding tetraethyl orthosilicate (TEOS) into perovskite, which prevents moisture attack on the perovskite by reacting with water and forming a blocking layer of SiO$^2.
In this work, a technique was developed to enhance the stability without any additives using electro-hydro atomization (electrospray) to deposit the perovskite (CH$_3NH$_3PbI$_3) material. The electrospray is an established technique for generating aerosols by liquid atomization using an electric field, which has also been used for thin film fabrication1. Herein, the electrospray was used to deposit perovskite thin films for solar cells. Electrospray provides a uniform film morphology compared to the conventional spin coating technique, resulting in high cell efficiency. Effects of various process parameters such as substrate-to-nozzle distance, flow rate and precursor concentration on the thin film morphology, and the solar cell efficiency were explored. The cells were fabricated and tested under ambient humidity conditions (30-55%). Furthermore, the stability of the devices was tested by exposing them to air for extended periods of time up to 600 hours. The perovskite solar cells had efficiencies as high as 11%. Mechanistic reasons for the enhanced stability will be elucidated.
Reference:
1. Kavadiya et al., Nanoscale, 2016, 8, 1868-1872.