Rubidium Ions Enhanced Crystallinity for Ruddlesden–Popper Perovskites

Abstract

Tailoring the organic spacing cations enables developing new Ruddlesden-Popper (RP) perovskites with tunable optoelectronic properties and superior stabilities. However, the formation of highly crystallized RP perovskites can be hindered when the structure of organic cations become complex. Strategies to regulate crystal growing process and grains quality remain to be explored. In this study, mixing Rb + ions in precursor solution is reported to significantly promote the crystallinity of phenylethylammonium (PEA +) based RP perovskites without impacting on the major orientation of perovskite grains, which leads to increased power conversion efficiencies from 12.5% to 14.6%. It is found that the added Rb + ions prefer to accumulate at crystal growing front and form Rb + ions-rich region, which functions as mild crystal growth inhibitor to retard the absorption and diffusion of organic cations at growing front and hence regulates crystal growing rate. The retarded crystal growth benefits PEA-based RP perovskite films with elevated crystal qualities and prolonged carrier recombination lifetimes. Similar increased crystallinity and photovoltaic performance are achieved in other RP perovskites with non-linear organic cations such as phenylmethylammonium (PMA +), 1-(2-naphthyl)-methanammoniun (NMA +) by adding Rb + ions, demonstrating using a small amount of growth inhibitor as a general route to regulate crystal growth. Layered perovskites such as Ruddlesden-Popper (RP) perovskites have been intensively studied in the past few years due to its better environmental stability [1-7] and less trend of ion migration. [8-10] Compared with its 3D counterparts, RP perovskite solar cells (PSCs) generally show lower power conversion

Charge‐Carrier Transport in Quasi‐2D Ruddlesden–Popper Perovskite Solar Cells

“…Reproduced under the terms of the CC‐BY Creative Commons Attribution 4.0 International license ( https://creativecommons.org/licenses/by/4.0). [ 88 ] Copyright 2020, The Authors, published by Wiley‐VCH.…”

Managing Phase Orientation and Crystallinity of Printed Dion–Jacobson 2D Perovskite Layers via Controlling Crystallization Kinetics

“…Significantly, the solar cell processed from the ternary solvent yields a dramatically improved efficiency of 16.29%, mainly as a result of an enhanced J SC of 17.10 mA cm -2 and an open-circuit voltage (V OC ) of 1.21 V. In particular, the obtained V OC of 1.21 V is among the highest values for DJ layered perovskite devices (Figure S13 and Table S4, Supporting Information). [29,[32][33][34][35] It is noticed that the efficiency improvement of the three devices processed from single to ternary solvent mainly originates from the increase in J SC , whereas the V OC s slightly increase and the FFs are almost constant. It is well known that V OC loss of solar cells is mainly related to nonradiative recombination due to the presence of a large number of trap states.…”

“…[18] However, 2D layered perovskites processed from solution typically exhibit low crystallinity and favor random or in-plane preferential orientations, resulting in poor charge transport across the perovskite layer. To surmount these deficiencies, hot-casting deposition, [25,26] slow annealing, [27] solvent engineering, [28,29] and tailoring composition and ligands [30][31][32][33][34] have been proposed to regulate the orientation of RP layered perovskites, leading to the latest record efficiency exceeding 18% for RP layered PSCs. [32,[35][36][37][38] In striking contrast, strategies for manipulating the crystal orientation of DJ layered perovskites have not been well established, partially due to the fact that they were first developed in 2018, [19] 4 years later than their relatively mature RP counterparts.…”

2D Hybrid Halide Perovskites: Structure, Properties, and Applications in Solar Cells

“…To date, various kinds of spacer cations for RP phase perovskite, such as BA, PEA, and amyl ammonium (AA), have been explored. [64][65][66][67][68][69][70] For the DJ phase structure with the formula of A′A n−1 B n X 3n+1 , diammonium spacer molecule (A′) possessed two ammonium cations in the terminal, which link two layers of inorganic slab together without a gap through terminal ionic bonding and covalent bond, forming a more stable crystal structure compared to RP phase. [71][72] Generally, in the DJ phase structure, the octahedrons above and below the spacer cation layer show nondisplacement (0, 0), thus perfectly stacked with each other.…”