The effect of SrI2 substitution on perovskite film formation and its photovoltaic properties via two different deposition methods?

Inorganic Chemistry Frontiers Pub Date: 2018-03-29 DOI: 10.1039/C8QI00131F

Abstract

The poisonous metal lead (Pb) is one of the key limiting factors for the large-scale industrial application of perovskite solar cells (PSCs). Here, we replaced some of the lead iodide (PbI2) with strontium iodide (SrI2) in the precursor solution to prepare Pb-less perovskite films and fabricate mesoscopic solar cells via the antisolvent-assisted single step method and the two-step spin-coating method. The effect of Sr substitution on the film formation and photovoltaic properties of perovskites was illuminated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and time-resolved photoluminescence (TRPL) analyses. The results show that, in the antisolvent-assisted single step method, Sr substitution has an impact on the formation of the intermediate phase, resulting in a lower coverage and an increased defect density of perovskite films. When the Sr content rises from 0 to 5 mol%, the device's power conversion efficiency (PCE) decreases from 15.22% to 6.37%. In the two-step spin-coating method, a moderate amount of SrI2 can change the chemical composition of the PbI2 precursor, resulting in less PbI2 and a decreased defect density in perovskite films. When the Sr content is 10 mol% in the PbI2 solution, the solar cell exhibits a considerable PCE of 15.52% under AM 1.5G solar illumination.

Graphical abstract: The effect of SrI2 substitution on perovskite film formation and its photovoltaic properties via two different deposition methods
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