Understanding the role of Tris(2-aminoethyl)amine in stabilizing mixed-cation perovskites under humid and thermal stress conditions

Abstract

Mixed organic–inorganic lead halide perovskites have emerged as promising optoelectronic materials for photovoltaic applications in the span of a few years. Mixed cation FA_1−xCs_x perovskites have been widely explored as a resolution to the phase instability issue in FAPbI₃ and CsPbI₃ perovskites. In this study, the impact of Tris(2-aminoethyl)amine (TAEA) on FA_0.83Cs_0.17Pb(I_0.90Br_0.10)₃ absorber layer stability under humid and thermal stress conditions has been investigated. Interestingly, the incorporation of TAEA in the perovskite precursor has resulted in enhanced structural and optoelectronic properties. Moreover, TAEA addition has led to greatly enhanced thermal and ambient stability. TAEA containing FA_0.83Cs_0.17Pb(I_0.90Br_0.10)₃ films retained their black phase even after 180 days of exposure to a highly humid environment with RH ∼ 60–70% and more than 7 days on exposure to continuous thermal stress at 85 °C along with high humidity and illumination. Therefore, the perovskite films fabricated with the optimized concentration of TAEA in FA_0.83Cs_0.17Pb(I_0.90Br_0.10)₃ perovskite have great potential for application in high performance devices with excellent thermal and ambient stability.