2D Intermediate Suppression for Efficient Ruddlesden–Popper (RP) Phase Lead-Free Perovskite Solar Cells

Abstract

2D Ruddlesden−Popper (2DRP) tin (Sn) perovskite solar cells (PSCs) play an irreplaceable role in advancing the commercialization of perovskite-based photovoltaic devices due to their low toxicity and improved stability. However, the efficiency of 2DRP Sn PSCs has not made a breakthrough owing to incompletely oriented crystal growth and poor film morphology, which is limited by a complex and uncontrollable crystallization process. Here, we first introduce the mixed spacer organic cations [n-butylamine (BA) and phenylethylamine (PEA)] in 2DRP Sn perovskite to control the crystallization process. We find that when the BA + and PEA + cowork to form [(BA 0.5 PEA 0.5 ) 2 FA 3 Sn 4 I 13 ] 2DRP perovskites, the intermediate phase impeding the homogeneous and ordered nucleation of the crystal is suppressed effectively, thus enabling a high-quality film morphology and improved crystal orientation. Benefitting from it, the power conversion efficiency (PCE) is improved to 8.82%, which is the highest one among the 2DRP Sn PSCs as far as we known.

Strategies for Improving the Stability of Tin‐Based Perovskite (ASnX3) Solar Cells

“…Later, Qiu et al explored the synergy between BA and PEA to control the crystallization process. [ 120 ] The interaction of BA and PEA could effectively inhibit the formation of mesophase during crystal growth, as shown in Figure 7b. As a result, a high‐quality thin film was obtained and the crystal orientation was improved.…”

“…Reproduce with permission. [ 120 ] Copyright 2019, American Chemical Society Publications. c) The perovskite structures of single crystals with HEAI proportions 0%, 40%, 80%, and 100% represented from left to right.…”

Low‐Dimensional Dion–Jacobson‐Phase Lead‐Free Perovskites for High‐Performance Photovoltaics with Improved Stability

“…Furthermore, the intermediate phase that blocked the uniform and orderly nucleation of the perovskite crystal was also effectively suppressed by using 2DRP (BA 0.5 PEA 0.5 ) 2 FA 3 Sn 4 I 13 , resulting in a high PCE (ca. 8.82 %) and improved stability . Thus, great progress has been made in the systematic study of 2DRP Sn‐based perovskites.…”

“…8.82 %) and improved stability. [28] Thus, great progress has been made in the systematic study of 2DRP Sn-based perovskites.A part from RP perovskite,2 Dp erovskites also contain am ore stable Dion-Jacobson (DJ) structure owing to the alternating hydrogen bonding interactions between diammonium cations and inorganic slabs. [29] Unlike RP phases (1/2, 1/2 displacements), the DJ phases feature short divalent + 2c ations between the layers,w hich yield an eclipsed stacking arrangement (0, 0d isplacements) that weakens the quantum confinement.…”

The Low-Dimensional Three-Dimensional Tin Halide Perovskite: Film Characterization and Device Performance

“…The addition of BAI had improved the PCE from 4.0% (3D) to 5.5%. The addition of EDI 2 doped device further improved the initial PCE to 7.4%, and the PCE continuously increased to 8.9% stored in a glovebox for over 1400 h [118]. Based on inverted FASnI3 PSCs, Chen et al introduced an ultrathin phenylethylammonium bromide (PEABr) between perovskite and HTL layer (Figure 15), leading to reduced trap states and suppressed charge recombination in 2D/3D PSCs.…”