2D Perovskites with Short Interlayer Distance for High‐Performance Solar Cell Application

Abstract

2D perovskites have emerged as one of the most promising photovoltaic materials owing to their excellent stability compared with their 3D counterparts. However, in typical 2D perovskites, the highly conductive inorganic layers are isolated by large organic cations leading to quantum confinement and thus inferior electrical conductivity across layers. To address this issue, the large organic cations are replaced with small propane-1,3-diammonium (PDA) cations to reduce distance between the inorganic perovskite layers. As shown by optical characterizations, quantum confinement is no longer dominating in the PDA-based 2D perovskites. This leads to considerable enhancement of charge transport as confirmed with electrochemical impedance spectroscopy, time-resolved photoluminescence, and mobility measurements. The improved electric properties of the interlayer-engineered 2D perovskites yield a power conversion efficiency of 13.0%. Furthermore, environmental stabilities of the PDA-based 2D perovskites are improved. PDA-based 2D perovskite solar cells (PSCs) with encapsulation can retain over 90% of their efficiency upon storage for over 1000 h, and PSCs without encapsulation can maintain their initial efficiency at 70 °C for over 100 h, which exhibit promising stabilities. These results reveal excellent optoelectronic properties and intrinsic stabilities of the layered perovskites with reduced interlayer distance.

Interlayer Cross‐Linked 2D Perovskite Solar Cell with Uniform Phase Distribution and Increased Exciton Coupling

“…This suggests that stronger interlayer interaction of thicker slices mitigates the quantum confine effect and/or the phase dispersity of (BDA)MA 3 Pb 4 I 13 ( n = 4) film is possibly suppressed, which will be further identified in the following. In the fabrication of solar cells, researchers add small amount of MACl and/or DMSO as additive to obtain highly oriented perovskite films and thus we also control the crystalline orientation and dispersity properties in this work . To simplify the notation, we denotes (BDA)MA 3 Pb 4 I 13 ( n = 4) film without additive as BDA‐control, (BDA)MA 3 Pb 4 I 13 ( n = 4) film with MACl and DMSO as BDA‐additive and (BA) 2 MA 3 Pb 4 I 13 ( n = 4) film without additive as BA‐control and (BA) 2 MA 3 Pb 4 I 13 ( n = 4) film with MACl and DMSO as BA‐additive.…”

“…Recently, a novel type of 2D perovskite called the Dion–Jacobson (DJ) structure was fabricated into PSCs, reported by Mao et al, using LA n −1 M n X 3 n + 1 , with divalent amino L molecules They used divalent organic ligands; i.e., 3‐(aminomethyl)piperidinium (3AMP) and 4‐(aminomethyl)piperidinium (4AMP) as the spacer and the solar cell exhibited a fairly good efficiency of 7.32%. Later on, Ma et alreport a 13% efficiency using 1,3‐diaminopropane as spacer with methylammonium chloride (MACl), dimethyl sulfoxide (DMSO) as additive. After that, Ahmad et al reported a highly efficient 13.3% DJ phase PSCs with thousand hours ultrahigh stability using the same molecule.…”

Enhancing High Humidity Stability of Quasi‐2D Perovskite Thin Films through Mixed Cation Doping and Solvent Engineering

“…Through simple solution processing, perovskite dimensionality could easily be confined: 3D to quasi‐2D to 2D by tuning the percentage of long organic cation composition. Quasi‐2D has the generic chemical formula of (RNH 3 ) 2 (A) n‐1 M n X 3n+1 where n is an integer and RNH 3 is a primary aliphatic or aromatic alkylammonium cation acting as a spacer between the perovskite layers, A, M, and X are monovalent organic cation, metal cations, and halide anions, together forming the perovskite framework . With high desorption energy of long organic chain, the moisture stability of quasi‐2D (low n values) is far above that of 3D perovskite .…”

Manipulation of Dipolar Polarization at Steady States for a Quasi‐2D Organic–Inorganic Hybrid Perovskite with a Nanorod Network

“…In the field, the ultimate goal is to have stable, highly efficient, large‐scale, inexpensive, and low‐toxicity lead‐free photovoltaics operating for longer lifetimes, to realize their future commercialization . To incorporate additional organic cations such as the 2‐phenylethylammonium cation (PEA + , C 6 H 5 (CH 2 ) 2 NH 3 + ), phenylmethylammonium (PMA + ) and n‐butyl‐ammonium (BA + ) cations with hydrophobic ligands forming 2D OIHP structures seem to be a unique way to inhibit moisture and oxygen damage . In addition, layered 2D perovskite structures are able to sustain structural stability even in nonambient conditions at higher pressures and lower temperatures .…”