Fabrication and Characterization of Protective Hole Transport Layer for Efficient and Durable Perovskite Solar Cell /

Abstract

Pakistan being an energy deficient country requires to trend toward renewable energy technologies. Solar energy is considered as most proficient form of renewable energy in Pakistan. Perovskite Solar cells were introduced in 2009, since then the efficiencies have surged from single digits to certified 27.3%. Perovskites, being an efficient technology seems to be the key to our energy requirements. Efficient charge transporting mediums add to the efficiency of the Perovskite Solar Cells. In conventional structures, hole transporting layer not only transports holes, it blocks electrons and also protects perovskite from external degradation factors. Hole transporting materials also contribute to increased stability and improved surface coverage of perovskite solar cells. Selection criterion for efficient hole transporting materials include high hole mobility and thermal stability, compatible ionization potential, external degradation factors resistance and low cost. In this work, a bilayer comprising of NiO and MWCNTs has been fabricated as an HTL. NiO HTL was deposited through spin coating and MWCNT thin film was deposited over it through Ultrasonic spray coating on the absorber layer for all the cells. Difference between sintered NiO film and non-sintered NiO film has been studied as well. All the layers were individually characterized and tested using XRD for phase identification, SEM/EDS for surface morphology, UV-Vis spectroscopy to study the optical properties, Hall Effect to check the electrical properties and Contact angle measurement for wettability studies of the samples prepared.