Moisture‐Resistant FAPbI₃ Perovskite Solar Cell with 22.25 % Power Conversion Efficiency through Pentafluorobenzyl Phosphonic Acid Passivation

Abstract

Perovskite solar cells (PSCs) have shown great promise for photovoltaic applications, owing to their low‐cost assembly, exceptional performance, and low‐temperature solution processing. However, the advancement of PSCs towards commercialization requires improvements in efficiency and long‐term stability. The surface and grain boundaries of perovskite layer, as well as interfaces, are critical factors in determining the performance of the assembled cells. Defects, which are mainly located at perovskite surfaces, can trigger hysteresis, carrier recombination, and degradation, which diminish the power conversion efficiencies (PCEs) of the resultant cells. This study concerns the stabilization of the α‐FAPbI3 perovskite phase without negatively affecting the spectral features by using 2,3,4,5,6‐pentafluorobenzyl phosphonic acid (PFBPA) as a passivation agent. Accordingly, high‐quality PSCs are attained with an improved PCE of 22.25 % and respectable cell parameters compared to the pristine cells without the passivation layer. The thin PFBPA passivation layer effectively protects the perovskite layer from moisture, resulting in better long‐term stability for unsealed PSCs, which maintain >90 % of the original efficiency under different humidity levels (40–75 %) after 600 h. PFBPA passivation is found to have a considerable impact in obtaining high‐quality and stable FAPbI3 films to benefit both the efficiency and the stability of PSCs.

Stability Issues of Perovskite Solar Cells: A Critical Review

“…Recently, Akram et al developed a moisture‐resistant PSC structure by passivating the surface of perovskite (FAPbI 3 ) by 2,3,4,5,6‐penta‐fluorobenzyl‐phosphonic acid (PFBPA) and achieved a PCE of 22.25%. [ 53 ] With scanning electron microscopy (SEM) images, the authors showed surface improvements by passivating with PFBPA. The devices were kept in 40−75% RH for 600 h for stability testing.…”

Organic Ammonium Halide Modulators as Effective Strategy for Enhanced Perovskite Photovoltaic Performance

“…[25,26] Apart from defect-related instability issues of PSCs, moisture or oxygen uptake are also considered to be important degradation mechanisms. [27] Owing to its crucial location in a regular n-i-p PSC, the HTL plays a key role in preventing environmental degradation caused by the contact with moisture and/or oxygen. [28] In particular, an intrinsically hydrophobic HTL can partially solve these above-mentioned issues due to the formation of a barrier between the highly hydrophilic ionic perovskite and the surrounding environment.…”

A Review of Perovskite Solar Cells

“…1 Standard solar spectral [7]. Hybrid organic-inorganic PSCs have had a great interest since 2009 with Power Conversion Efficiency (PCE) which raised exponentially from 3.8% [8] to 6.5% in 2011 [7] to about 23.3 % in 2016 [7] and reaches 25.2 % by 2021 [9][10][11][12][13] as shown in Fig. 2.…”