Side‐Chain Functionalized Polymer Hole‐Transporting Materials with Defect Passivation Effect for Highly Efficient Inverted Quasi‐2D Perovskite Solar Cells

Abstract

Compared with inverted 3D perovskite solar cell (PSCs), inverted quasi‐2D PSCs have advantages in device stability, but the device efficiency is still lagging behind. Constructing polymer hole‐transporting materials (HTMs) with passivation functions to improve the buried interface and crystallization properties of perovskite films is one of the effective strategies to improve the performance of inverted quasi‐2D PSCs. Herein, two novel side‐chain functionalized polymer HTMs containing methylthio‐based passivation groups are designed, named PVCz‐SMeTPA and PVCz‐SMeDAD, for inverted quasi‐2D PSCs. Benefited from the non‐conjugated flexible backbone bearing functionalized side‐chain groups, the polymer HTMs exhibit excellent film‐forming properties, well‐matched energy levels and improved charge mobility, which facilitates the charge extraction and transport between HTM and quasi‐2D perovskite layer. More importantly, by introducing methylthio units, the polymer HTMs can enhance the contact and interactions with quasi‐2D perovskite, and further passivating the buried interface defects and assisting the deposition of high‐quality perovskite. Due to the suppressed interfacial non‐radiative recombination, the inverted quasi‐2D PSCs using PVCz‐SMeTPA and PVCz‐SMeDAD achieve impressive power conversion efficiency (PCE) of 21.41% and 20.63% with open‐circuit voltage of 1.23 and 1.22 V, respectively. Furthermore, the PVCz‐SMeTPA based inverted quasi‐2D PSCs also exhibits negligible hysteresis and considerably improved thermal and long‐term stability.

Performance Enhancement of Flexible Perovskite Solar Cells Enabled by Ammonium Halide Passivation

“…Compared with the control, the PL intensity of the PACl perovskite film was stronger, indicating that PACl involvement reduced the perovskite thin defects and thus improved the film quality. Figure c shows the TRPL spectra of the control and PACl perovskite films, which were fitted with double exponential decay using formula Y = A 1 exp ( − t τ 1 ) + A 2 .25em exp ( − t τ 2 ) + γ 0 where A 1 and A 2 are the proportion of the multiple lifetime processes, τ 1 and τ 2 are the fluorescence lifetime value of each process, t is the independent variable of the horizontal axis, and γ 0 is the offset. The average lifetime (τ avg ) is calculated by formula τ normala normalv normalg = A 1 τ 1 2 + A 2 τ 2 2 A 1 τ 1 + τ 2 A 2 The specific results of the fitting are listed in Table S3.…”

Enhanced Perovskite Photovoltaics with Non-conjugated Polymers: Recent Developments and Future Prospects

“…Recently, the Yin group designed two new side-chain functionalized polymers for use as HTMs in inverted quasi-2D PSCs. These polymers, named PVCz-SMeTPA and PVCz-SMeDAD, incorporate methylthio passivation groups.…”

“…Chemical structures of PVCz-SMeTPA and PVCz-SMeDAD and schematic illustration of buried interface passivation of quasi-2D perovskite by the PVCz-SMeTPA. Reproduced with permission from ref . Copyright 2023 Wiley-VCH.…”

Halogen substitution of perinone-based cathode interfacial materials for high-efficiency inverted perovskite solar cells

“…7,8 The inverted PSCs have exhibited a boom in PCE following the introduction of self-assembled monolayers and passivation methods. 9–15…”