Polyfluorene Copolymers as High‐Performance Hole‐Transport Materials for Inverted Perovskite Solar Cells

Abstract

Inverted perovskite solar cells (PSCs) that can be entirely processed at low temperatures have attracted growing attention due to their cost‐effective production. Hole‐transport materials (HTMs) play an essential role in achieving efficient inverted PSCs, as they determine the effectiveness of charge extraction and recombination at interfaces. Herein, three polyfluorene copolymers (TFB, PFB, and PFO) are investigated as HTMs for construction of inverted PSCs. It is found that the photovoltaic performance of the solar cells is closely correlated with the electronic properties of the HTMs. Due to its high mobility along with the favored energy‐level alignment with perovskite, TFB shows superior charge extraction and suppressed interfacial recombination than PFB‐ and PFO‐based devices, which delivers a high efficiency of 18.48% with an open‐circuit voltage (VOC) of up to 1.1 V. In contrast, the presence of a large energy barrier in the PFO‐based devices results in substantial losses in both VOC and photocurrent. These results demonstrate that TFB can serve as a superior HTM for inverted PSCs. Moreover, it is anticipated that the performance of the three HTMs identified here might guide the molecular design of novel HTMs for the manufacture of highly efficient inverted PSCs.

Nanoparticle Wetting Agent for Gas Stream-Assisted Blade-Coated Inverted Perovskite Solar Cells and Modules

“…73 This study revealed the proof of concept that oxide NPs can improve wetting of the precursor solution on PTAA. 73,74 Nevertheless, all layers of the presented devices were deposited mainly in the standard (n-i-p) device architecture 71,72 and merely by hardly scalable spin coating 73,74 without a full investigation on a scalable printing technique.…”

Examining the Interfacial Defect Passivation with Chlorinated Organic Salt for Highly Efficient and Stable Perovskite Solar Cells

“…[ 17 ] Moreover, previously reported work indicated that trap states mainly located at the interfaces of multilayers of whole device (called interface defects) and at the perovskite surface (called surface defects), which are effectively related to the energy level matching, hysteresis, charge carriers dynamics, and the long‐term environmental and operational stability. [ 18–22 ] Therefore, it is indispensable to explore an impressive way to diminish the defects, particularly at the interfaces, for acquiring the high‐efficient and stable PSCs. Currently, there are lots of approaches to improve the performance and stability of PSCs, containing additive engineering, using additive into a perovskite absorber layer and interface engineering, modifying the hole transport layer (HTL)/perovskite or perovskite/electron transport layer (ETL) interfaces.…”

Biopolymer passivation for high-performance perovskite solar cells by blade coating

“…Hybrid perovskite solar cells (PSCs) have emerged as promising candidates for the next-generation thin-film solar technologies, mainly due to their low-cost materials, simple solution fabrication process and high power-conversion-efficiency (PCE). The certified PCE of PSCs has skyrocketed from 3.8% to an impressive level of 25.2% in the past decade [1][2][3][4], which is enabled by a combined efforts in optimizing the perovskite compositions [5], interface engineering [6][7][8][9][10][11][12], and defect passivation [13][14][15]. In particular, thin films of polycrystalline perovskite processed from solution tend to produce high density of defects and exhibit a large degree of electronic disorder.…”