Stabilizing the Efficiency Beyond 20% with a Mixed Cation Perovskite Solar Cell Fabricated in Ambient Air under Controlled Humidity

Abstract

composition of lead halide perovskite by introducing mixed cation and halide have stabilized the solution process to make uniform large grain perovskite, which ultimately led to high efficiency and durability of solar cell. Mixed perovskites are durable against exposure to heat and moisture while the single cation perovskites such as methyl ammonium halide (MAPbX 3 ), formamidinium lead halide (FAPbX 3 ), and cesium lead halide (CsPbX 3 , X = I or Cl or Br) exhibit relatively low stability in ambient circumstances. [9][10][11][12] For compatible high efficiency and durability, mixed cation (formamidium (FA), methylammonium (MA), and cesium (Cs)) based perovskite is a promising solution. Seok and co-workers [10] have investigated the compositional engineering of (FAPbI 3 ) 1−x (MAPbBr 3 ) x compounds in PSCs while Graetzel and co-workers [13] have shown PSCs efficiency beyond 20% with FA/MA mix cations. Park and coworkers [14] studied the effect of Cs addition to FA in planar heterojunction PSCs to find higher stability of Cs-added composition than pure FAPbI 3 against moisture and light illumination. Saliba et al. [15] have discovered that the addition of Cs into FA/MA can improve the crystal growth and morphology of the perovskite which facilitates efficient charge collection and thereby stabilizes the high efficiency of PSC. More recently, Tan et al. produced highly efficient triple cation based perovskite device via contact passivation strategy using chlorine-capped TiO 2 (Cl-TiO 2 ) colloidal nanocrystal as a compact layer in planar architecture. [16] Triple (Cs/FA/MA) cationbased perovskite materials exhibit average PCE fairly exceeding 20% with stable performance against long time exposure to ambient atmosphere. Such a robust performance of high quality triple cation perovskite has been obtained in laboratory by atmosphere-controlled crystallization processes including post annealing of perovskite crystals in the nitrogen filled glove box whereas the glove box treatment process is a practical issue for large scale industrialization. It is desired that all solution processes be designed to meet ambient air conditions. In other words, it is of utmost importance to screen these perovskite materials in controlled humidity air atmosphere conditions toward their reproducibility, phase stability, preparation parameter fluctuations dependency, and nonetheless high efficiency. Perovskite solar cells have evolved to have compatible high efficiency and stability by employing mixed cation/halide type perovskite crystals as pinhole-free large grain absorbers. The cesium (Cs)-formamidium-methylammonium triple cation-based perovskite device fabricated in a glove box enables reproducible high-voltage performance. This study explores the method to reproduce stable and high power conversion efficiency (PCE) of a triple cation perovskite prepared using a one-step solution deposition andlow-temperature annealing fully conducted in controlled ambient humidity conditions. Optimizing the perovskite grain size by Cs concentratio...

Activating Old Materials with New Architecture: Boosting Performance of Perovskite Solar Cells with H2O‐Assisted Hierarchical Electron Transporting Layers

“…Second, as shown in Figures 3a-f and 4, introducing the H-m-TiO 2 ETLs could enhance the crystallization of the MAPbI 3 films and reduce the grain boundaries and trap-states density. [29,30] The recombination processes always strongly determine the properties of solar cells at open circuit condition because there is no current extraction and all the photo-generated carriers recombine. This logarithmic relationship is consistent with the fundamental relationship V oc = nk B T/q Adv.…”

Ultrathin Nanosheets of Oxo‐functionalized Graphene Inhibit the Ion Migration in Perovskite Solar Cells

“…It can be seen that, unlike conventional graphene and other oxygenated/oxidized/oxygen-containing graphene derivatives (e.g., graphene oxide), oxo-G/DA possesses organosulfur groups on the basal plane of graphene and dodeclyamonium groups anchored to those for charge neutralization (C 12 H 25 NH 3 + ). 2020, 10,1902653 in the range of 50-800 nm, and the thickness is within 1 nm. [25] The amino chain can promote the dispersion of oxo-G in the perovskite precursor and even form a large number of monolayer-distributed structures.…”

“…2020, 10,1902653 of 0.2° for 20 s. The time-of-flight secondary ion mass spectrometry (Model TOF-SIMS 5, ION-TOF GmbH) was measured with the pulsed primary ions from a Cs + (2 keV) liquid-metal ion gun for the sputtering and a Bi+ pulsed primary ion beam for the analysis (30 keV). The light intensity was calibrated with a silicon reference cell from Fraunhofer Institute for Solar Energy Systems.…”

“…[9][10][11][12] For mixed cation/halide perovskites, despite good optoelectronic properties, the mixing of multiple cations and halogens is prone to localized ionic enrichment during preparation, annealing, and operation. By introducing mixed cations and halide to adjust the composition of the organicinorganic hybrid perovskite, the crystal structure of the perovskite can be effectively improved, which ultimately led to the increased stability and efficiency of the PSCs.…”

Nitrogen Soaking Promotes Lattice Recovery in Polycrystalline Hybrid Perovskites

“…Their outstanding yields in luminescence, electroluminescence, [1,2] and photoelectric conversions, [3][4][5][6][7] combined with the easy solution processing, promise large-scale production, morphology of the layer and indeed has a general valence for any laboratory. Their outstanding yields in luminescence, electroluminescence, [1,2] and photoelectric conversions, [3][4][5][6][7] combined with the easy solution processing, promise large-scale production, morphology of the layer and indeed has a general valence for any laboratory.…”