Investigation of moisture stability and PL characteristics of terpineol-passivated organic–inorganic hybrid perovskite

Abstract

This work presents a novel method for preparing perovskite films using a simple processing technique. Perovskite paste was prepared by dispersing an equimolar mix of PbI 2 and methyl ammonium iodide powders into terpineol with stirring. From these precursors, perovskite films were fabricated using doctor blading and drying for 24 h at room temperature. The prepared films were then placed into relative humidity (RH) levels of 30, 50, and 70 % to test the moisture stability. The crystal structure, phases, and morphology were investigated with XRD and SEM/EDX. These samples exhibited good stability against long time exposure to moisture for 70 days. The XRD results showed that samples stored at RH 70 % contained only a small amount of hydrate compound after 70 days storage, while in the sample stored at RH 50 %, the formation of PbI 2 was observed. The sample at RH 30 % manifested almost no change when stored for the same storage period. We attribute the enhanced moisture stability, compared with the spin-coated samples, to a passivated surface of the perovskite film by terpineol which exhibits a hydrophobic moiety. Time-resolved photoluminescence measurements show that the passivation of surface defect states by the formation of either PbI 2 or hydrated compound leads to prolonged charge carrier recombination times.Graphical Abstract

The effect of storage cycle on improvement in the photovoltaic parameters of planar triple cation perovskite solar cells

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