Multifunctional π‐Conjugated Additives for Halide Perovskite

Abstract

Additive is a conventional way to enhance halide perovskite active layer performance in multiaspects. Among them, π‐conjugated molecules have significantly special influence on halide perovskite due to the superior electrical conductivity, rigidity property, and good planarity of π‐electrons. In particular, π‐conjugated additives usually have stronger interaction with halide perovskites. Therefore, they help with higher charge mobility and longer device lifetime compared with alkyl‐based molecules. In this review, the detailed effect of conjugated molecules is discussed in the following parts: defect passivation, lattice orientation guidance, crystallization assistance, energy level rearrangement, and stability improvement. Meanwhile, the roles of conjugated ligands played in low‐dimensional perovskite devices are summarized. This review gives an in‐depth discussion about how conjugated molecules interact with halide perovskites, which may help understand the improved performance mechanism of perovskite device with π‐conjugated additives. It is expected that π‐conjugated organic additives for halide perovskites can provide unprecedented opportunities for the future improvement of perovskite devices.

A Novel Multiple‐Ring Aromatic Spacer Based 2D Ruddlesden–Popper CsPbI3Solar Cell with Record Efficiency Beyond 16%

“…[34] Unlike the conventional VBM and CBM of most 2D perovskite materials located on the inorganic layer, the π-electrons in 1-NA, BIDZ, and DPDA molecules have a significant contribution to CBM, which can lead to a reduced bandgap of layered perovskites, and promote the absorption of photons by the perovskite to generate more electron-hole pairs and facilitate charge transport. Meanwhile, we speculate that the 𝜋 and 𝜋* states located in the near-edge CB can also facilitate the electronic coupling between the organic layers and the inorganic layers, optimizing the mobility of carriers and more favorable photovoltaic performance, which is consistent with that reported by Xiao et al [35] This is also proved by the DOS result under other dimensions (n = 2, 3) (Figure S3a-d, Supporting Information).…”

High‐Performance Perovskite Photovoltaics by Heterovalent Substituted Mixed Perovskites

“…A boosted stability observed from the PSCs based on the PEA 2 PbI 4 :MAPbI 3 thin film reveals that the 2D perovskites indeed play a very important role in preventing perovskites from moisture and air. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Moreover, superior stability observed from the PSCs based on the Nd 3+ -substituted PEA 2 PbI 4 :MAPbI 3 thin film indicates that the substitution of Pb 2+ by heterovalent Nd 3+ could restrict the ion migration and suppress defects within the resultant perovskites, resulting in boosted stability of perovskites.…”

“…[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] To circumvent this problem, conjugated organic molecules as the organic spacers were used to create 2D perovskites. [29][30][31][32][33][34] For example, we demonstrated high-performance PPVs based on the 2D:3D mixed perovskites, where 2D perovskites were based on conjugated organic molecules, 3-phenyl-2-propen-1-amine and 4-fluorobenzylammonium. [32][33][34] On the other hand, previous studies indicated that the utilization of metal cations to partially substitute Pb 2+ can boost the charge transport of 3D perovskites.…”

High Efficiency Inorganic Perovskite Solar Cells Based On Low Trap Density and High Carrier Mobility CsPbI3 Films

“…[4] existence of intermolecular π-π interaction. [28] It could be speculated that the functional group would improve the ability to transfer carriers through the perovskite interfaces and GBs.…”