Moisture-triggered fast crystallization enables efficient and stable perovskite solar cells

Abstract

Understanding the function of moisture on perovskite is challenging since the random environmental moisture strongly disturbs the perovskite structure. Here, we develop various N2-protected characterization techniques to comprehensively study the effect of moisture on the efficient cesium, methylammonium, and formamidinium triple-cation perovskite (Cs0.05FA0.75MA0.20)Pb(I0.96Br0.04)3. In contrast to the secondary measurements, the established air-exposure-free techniques allow us directly monitor the influence of moisture during perovskite crystallization. We find a controllable moisture treatment for the intermediate perovskite can promote the mass transportation of organic salts, and help them enter the buried bottom of the films. This process accelerates the quasi-solid-solid reaction between organic salts and PbI2, enables a spatially homogeneous intermediate phase, and translates to high-quality perovskites with much-suppressed defects. Consequently, we obtain a champion device efficiency of approaching 24% with negligible hysteresis. The devices exhibit an average T80-lifetime of 852 h (maximum 1210 h) working at the maximum power point.

Direct In Situ Conversion of Lead Iodide to a Highly Oriented and Crystallized Perovskite Thin Film via Sequential Deposition for 23.48% Efficient and Stable Photovoltaic Devices

“…As shown in Figure g,i and Figure S7, SEM results show that the use of SnO 2 or our specially selected PTAA as the substrate has little effect on the perovskite morphology, and both of them can reflect the effect of FAFa treatment on the perovskite. At the same time, other studies have also shown that the method of using PTAA to study the properties of the perovskite buried interface is reliable. , …”

“…At the same time, other studies have also shown that the method of using PTAA to study the properties of the perovskite buried interface is reliable. 41,53 XPS was performed to analyze the bonding state of O, Pb, and I in the top and bottom sides of the perovskite films in Figure 3c,d and Figure S8. Compared with the pristine perovskite−ETL interface (hereafter denoted as FAFa-0bottom), the binding energy of O 1s of the perovskite-ETL interface treated with 2 mg/mL FAFa (FAFa-2-bottom) is decreased by 0.15 eV, and the binding energy of Pb 4f is increased by 0.15 eV, as shown in Figure 3c,d.…”

Water Additives Improve the Efficiency of Violet Perovskite Light-Emitting Diodes

“…The impact of H2O on perovskite solar cells has been widely studied. [36][37][38][39][40][41][42] Moderate water additives/moisture could accelerate the crystal formation and enhance the texture-orientation of the perovskite films, which could lead to higher efficiency of perovskite solar cells. 37,38,40,42 However, few studies have demonstrate moisture treatment for perovskite light-emitting diodes.…”

“…[36][37][38][39][40][41][42] Moderate water additives/moisture could accelerate the crystal formation and enhance the texture-orientation of the perovskite films, which could lead to higher efficiency of perovskite solar cells. 37,38,40,42 However, few studies have demonstrate moisture treatment for perovskite light-emitting diodes. 43 The intentional addition of water to the perovskite precursor solutions was inspired by previous work with CH3NH3PbBr3 thin films, where a water additive was used to tune the crystallization in the spin coating process.…”

The synthesis of metal halide perovskite nanocrystals: surface and interface engineering

“…According to past reports, it has been demonstrated that traces of water could also play a positive role in the formation of perovskite films. 90 The optimal humidity could favour the formation of perovskite and promote the crystallization with the improved PL. 91,92 In such bi-phase and multiphase systems, a stable interface may form between different phases, promoting the ion exchange channels.…”