High quality perovskite films fabricated from Lewis acid–base adduct through molecular exchange

Abstract

High quality CH3NH3PbI3 perovskite films without residual PbI2 are fabricated from the Lewis adduct of PbI2·xDMF through molecular exchange. The photovoltaic performances of the perovskite solar cells are thus improved significantly.

The Impact of a Dynamic Two‐Step Solution Process on Film Formation of Cs0.15(MA0.7FA0.3)0.85PbI3 Perovskite and Solar Cell Performance

“…Among those applications, Fu et al compared the PbI 2 (DMF) and PbI 2 (dimethyl sulfoxide (DMSO)) complex precursors and found that perovskite film from PbI 2 (DMSO) shows reduced defects with higher quality . Cao et al claimed that when PbI 2 precipitates from DMF solution, the “Lewis acid–base adducts” of PbI 2 ‐ x DMF complex allows for the expansion of the lattice of PbI 2 , for MAI diffusion during the second immersion step . Yang et al also employed the PbI 2 ‐DMSO complex to promote a pre‐expanded phase, retarding the rapid reaction between PbI 2 and organic iodide in order to achieve a complete conversion to formamidinium lead iodide (FAPbI 3 ) .…”

Enhanced performance of perovskite solar cells by strengthening a self-embedded solvent annealing effect in perovskite precursor films

“…The clean of FTO substrates, deposition of TiO 2 blocking layers, and TiO 2 mesoporous layers have been described in details in our previous report. 24 Perovskite lms were fabricated through a modied two-step method. 24 A layer of PbI 2 precursor lm was rstly spin-coated from PbI 2 /DMF (1.4 M) solution at 5500 rpm for 30 s, and then dipped into a solution of CH 3 NH 3 I (MAI)/2propanol with concentration 30 mg mL À1 for 60 s to prepare perovskite precursor lm.…”

“…24 Perovskite lms were fabricated through a modied two-step method. 24 A layer of PbI 2 precursor lm was rstly spin-coated from PbI 2 /DMF (1.4 M) solution at 5500 rpm for 30 s, and then dipped into a solution of CH 3 NH 3 I (MAI)/2propanol with concentration 30 mg mL À1 for 60 s to prepare perovskite precursor lm. Here, we employ two different annealing approach on perovskite precursor lm: traditional annealing approach without protective layer and sealed-style annealing approach with a protective layer onto perovskite precursor lm.…”

“…[21][22][23] In our previous work, we fabricated smooth perovskite lms from Lewis adducts through molecular exchange through a modied twostep method. 24 The smooth perovskite lms were ascribed to the solvent modulated the formation of perovskite lm during molecular exchange and annealing process. 25 It is solvent included perovskite precursor lm, which is the product obtained aer molecule exchange between solvent and MAI.…”

Solvent and Spinning Speed Effects on CH3NH3PbI3 Films Deposited by Spin Coating

“…Since 2009, a great interest has been paid to organometallic lead halide perovskite (CH 3 NH 3 Pb X 3 , where X =Br and Cl) films that have proved to have a high performance in photovoltaic conversion with power conversion efficiency exceeding 22% and light‐emitting diodes and laser applications . Among these inorganic–organic hybrid perovskite family, methylammonium lead triiodide (CH 3 NH 3 PbI 3 ) was first used for solar cell applications . Perovskite materials combine the properties of inorganic and organic materials, resulting in excellent qualities such as direct bandgap, high absorption coefficient, low exciton binding energy, and large carrier diffusion lengths of 100 nm, which can reach 1000 nm by introducing chlorine .…”