Managing Secondary Phase Lead Iodide in Hybrid Perovskites via Surface Reconstruction for High‐Performance Perovskite Solar Cells with Robust Environmental Stability

Abstract

Rationally managing the secondary‐phase excess lead iodide (PbI2) in hybrid perovskite is of significance for pursuing high performance perovskite solar cells (PSCs), while the challenge remains on its conversion to a homogeneous layer that is robust stable against environmental stimuli. We herein demonstrate an effective strategy of surface reconstruction that converts the excess PbI2 into a gradient lead sulfate‐silica bi‐layer, which substantially stabilizes the perovskite film and reduces interfacial charge transfer barrier in the PSCs device. The perovskite films with such bi‐layer could bear harsh conditions such as soaking in water, light illumination at 70 % relative humidity, and the damp‐thermal (85 °C and 30 % humidity) environment. The resulted PSCs deliver a champion efficiency up to 24.09 %, as well as remarkable environmental stability, e.g., retaining 78 % of their initial efficiency after 5500 h of shelf storage, and 82 % after 1000 h of operational stability testing.

Rethinking the Role of Excess/Residual Lead Iodide in Perovskite Solar Cells

“…[4] Recently, Wang et al converted excess PbI 2 into a gradient PbSO 4 -SiO 2 bilayer. [117] This surface reconstruction strategy reduced the interfacial charge transfer barrier in the perovskite solar cell devices and improved the stability of the films.…”

Mutually Tuned Dual Additive Engineering Synergistically Enhances the Photovoltaic Performance of Tin-Based Perovskite Solar Cells

“…They can be fitted according to the equation J sc ∝ I α . 73 The α values for Controland GABr&MAOCN-PSCs are 0.987 and 0.996, respectively. They are close to 1, confirming that the bimolecular recombination in Control-and GABr&MAOCN-PSCs is negligible.…”

“…They are close to 1, confirming that the bimolecular recombination in Control-and GABr&MAOCN-PSCs is negligible. 73,74 Valuation of the electrical impedance spectrum (EIS) provides insights into series resistance (R s ) and charge recombination resistance (R rec ) in T-PSCs. Figure 4(e,f) presents the Nyquist plots and dark J−V curves of Controland GABr&MAOCN-PSCs, respectively.…”

Managing Excess Lead Iodide with Ordered Distribution and Reduced Photoactivity via Chelating Ligands for Stable Inverted Perovskite Solar Cells

“…14,17−20 Posttreatment of perovskite films aims to chemically react with the residual PbI 2 , which can effectively improve the device efficiency and stability. 21 You et al proposed to stabilize the perovskite by converting excess PbI 2 into inactive (PbI 2 ) 2 RbCl, thereby improving the stability of FAPbI 3 PSCs. 22 To completely eliminate detrimental effects of excess PbI 2 residues, a chemical polishing strategy was developed to remove it from the resulting perovskite surface.…”

“…Many strategies have been implemented to eliminate the detrimental effect of excess PbI 2 residues in PSCs. ,− Post-treatment of perovskite films aims to chemically react with the residual PbI 2 , which can effectively improve the device efficiency and stability . You et al proposed to stabilize the perovskite by converting excess PbI 2 into inactive (PbI 2 ) 2 RbCl, thereby improving the stability of FAPbI 3 PSCs .…”