Uncovering Aging Chemistry of Perovskite Precursor Solutions and Anti‐aging Mechanism of Additives

Abstract

The aging of precursor solutions is the major stumbling block for the commercialization of perovskite solar cells (PSCs). Herein, for the first time we used the state-of-the-art in situ liquid time-of-flight secondary ion mass spectrometry to molecularly explore the perovskite precursor solution chemistry. We identified that the methylammonium and formamidinium cations and the I À anion are the motivators of the aging chemistry. Further, we introduced two kinds of Lewis bases, triethyl phosphate (TP) and ethyl ethanesulfonate (EE), as new additives in the solution and unraveled that both of them can protect the reactive cations from aging through weak interactions. Significantly, TP is superior to EE in enhancing long-term solution stability as it can well-maintain the internal interaction structures within the solution phase. The PSC derived from a fresh TPdoped solution delivered a high power conversion efficiency of 23.06 %, 92.23 % of which remained in that from a 21-day-old solution.

Modulation of Colloidal Assembly Behavior Enables Printable Low‐Dimensional Perovskite Photovoltaics

“…To further verify this speculation, we firstly applied our advanced in situ liquid ToF‐SIMS [33–36] (Figure 3a) to visualize the large spacer cations involved colloidal composition (see Supporting Information Note 2). The mass spectrum and representative 2D ion mapping of the MA and FA precursor solutions are shown in Figure 3b and Supporting Information Figures S9–S11.…”

Modulation of Colloidal Assembly Behavior Enables Printable Low‐Dimensional Perovskite Photovoltaics

“…To further verify this speculation, we firstly applied our advanced in situ liquid ToF-SIMS [33][34][35][36] (Figure 3a) to visualize the large spacer cations involved colloidal composition (see Supporting Information Note 2). The mass spectrum and representative 2D ion mapping of the MA and FA precursor solutions are shown in Figure 3b and Supporting Information Figures S9-S11.…”

Advances to Stabilize Photoactive Phase of FAPbI3 Perovskite†

“…[ 31 ] The aging effect will influence the forms of perovskite colloid in precursor solution, and the impurities contained in the solution can participate in the film formation process thereby affecting the stability and efficiency of PSCs. [ 35 ] Therefore, the instability of the perovskite precursor solution is the prior problem that needs to be well‐addressed and solved.…”