Lewis Acid–Base Interaction-Induced Porous PbI₂ Film for Efficient Planar Perovskite Solar Cells

Abstract

The quality of perovskite film is an important factor influencing the photovoltaic properties of solar cells, which is greatly affected by deposition methods. Here, Lewis acid−base interaction-induced porous PbI 2 film is obtained by 4-tert-butylpyridine (TBP) vapor treatment method. X-ray diffraction, Raman spectroscopy, and Fourier transform infrared characteristics indicate that a new complex including both TBP and PbI 2 molecules was formed by Lewis acid−base reaction. A continuous, uniform, and PbI 2 -free perovskite film with large grains was obtained from the porous PbI 2 reacted completely with CH 3 NH 3 I. As a result, a promising power conversion efficiency of ∼18% is achieved in planarheterojunction perovskite solar cells. Furthermore, via controlling the vapor treatment time, the porosity and thickness of PbI 2 film can be readily adjusted, and the unexpected mesoporous perovskite film was first fabricated. Our work demonstrates the preparation of porous PbI 2 films by Lewis base vapor treatment for highly efficient planar perovskite solar cells.

Short‐Term Stability of Perovskite Solar Cells Affected by In Situ Interface Modification

“…In previous reports, similar peaks at 2 θ = 7.5° in the XRD patterns originated from the PbI 2 ·2tBP complex, which was especially characterized in recent results . The appearance order of these two peaks at 2 θ = 7.5° and 12.1° is very interesting.…”

Phosphine Oxide Derivative as a Passivating Agent to Enhance the Performance of Perovskite Solar Cells

“…However, the peak intensity was reduced by the deposition of THPPO. As PbI 2 is a well-known Lewis acid, the reduction of the PbI 2 peak intensity of the THPPO-treated films can be explained by the formation of the PbI 2 ·THPPO adduct (Figure c). , …”

“…As PbI 2 is a well-known Lewis acid, the reduction of the PbI 2 peak intensity of the THPPO-treated films can be explained by the formation of the PbI 2 •THPPO adduct (Figure 2c). 57,58 The surface morphology of the perovskite films treated with various concentrations of THPPO was observed by scanning electron microscopy (SEM) images (Figure 3a). The pristine film showed sparsely distributed bright grains, which can be attributed to the residual PbI 2 .…”

Rapid hybrid perovskite film crystallization from solution

“…DMSO, NMP, HMPA) with higher boiling points and improved interaction with PbI 2 , as indicated by their higher D N s, has been used to improve the grain coarsening process during solvent annealing after spin-coating of PbI 2 . 133,134,[143][144][145][146][147][148][149][150][151] On the other hand, acetonitrile (D N (MeCN) = 14.1 kcal mol À1 ) as an example of a weakly Lewis basic solvent has also been used as an additive in PbI 2 /DMF to improve grain morphology and roughness of the final perovskite film. 151,152 In other instances, the PbI 2 ÁxSol complexes formed before thermal annealing have been treated directly with the desired organic halide and shown to improve the final performance of PSCs.…”