Boosting Long-Term Stability of Pure Formamidinium Perovskite Solar Cells by Ambient Air Additive Assisted Fabrication

Abstract

Due to the high industrial interest for perovskite-based photovoltaic devices, there is an urgent need to fabricate them under ambient atmosphere, not limited to low relative humidity (RH) conditions. The formamidinium lead iodide (FAPI) perovskite α-black phase is not stable at room temperature and is challenging to stabilize in an ambient environment. In this work, we show that pure FAPI perovskite solar cells (PSCs) have a dramatic increase of device long-term stability when prepared under ambient air compared to FAPI PSCs made under nitrogen, both fabricated with N -methylpyrrolidone (NMP). The T 80 parameter, the time in which the efficiency drops to 80% of the initial value, increases from 21 (in N 2 ) to 112 days (in ambient) to 145 days if PbS quantum dots (QDs) are introduced as additives in air-prepared FAPI PSCs. Furthermore, by adding methylammonium chloride (MACl) the power conversion efficiency (PCE) reaches 19.4% and devices maintain 100% of the original performance for at least 53 days. The presence of Pb–O bonds only in the FAPI films prepared in ambient conditions blocks the propagation of α- to δ-FAPI phase conversion. Thus, these results open the way to a new strategy for the stabilization in ambient air toward perovskite solar cells commercialization.

Development of formamidinium lead iodide-based perovskite solar cells: efficiency and stability

“… 119 Salim et al also further showed that the long-term stability of NMP additive-pure FAPbI 3 PSCs shows a dramatic increase when prepared under ambient air compared to PSCs made under nitrogen. 120 Ma et al incorporated methylamine thiocyanate as a stabilizer, and high-quality and stable α-phase FA-based perovskites in ambient 50 ± 5% RH even at room temperature. 121 Only Huang et al 119 really prepared the FAPbI 3 PSCs at high humidity in the atmospheric air and obtained excellent stability.…”

Understanding the stability origins of ambient stable CsPbI2Br inorganic halide perovskites

“…1f displays the O 1s peaks for the perovskite lms prepared with different atmospheres. The O 1s peaks are located at 529.8 eV and 531.1 eV in the air-CsPbI 2 Br lm, which are attributed to oxygen atoms in metal-oxide bonds 18 and superoxide (O 2…”

In Situ Graded Passivation via Porphyrin Derivative with Enhanced Photovoltage and Fill Factor in Perovskite Solar Cells

“…As presented in Figure 2f,g, the peaks at 14.11°, 24.45°, and 28.28° were indexed to the (100), (111), and (200) lattice planes of the typical perovskite, respectively. [ 36 ] Compared to the control film, there are no additional peaks, and no peak shifts for the films treated by ZnPP treatment, manifesting that the ZnPP molecular was only attached to the interface and surface of perovskite film and did not change the crystal structure of the perovskite. [ 37 ] However, the target samples exhibited stronger diffraction intensities and narrower full widths at half maximum (FWHM) at 2 θ = 14.11°, especially for the 0.05 mg mL −1 ZnPP‐treated film, in which the FWHM decreased from 0.090° (control film) to 0.073° (Figure 2g).…”