Enhanced Efficiency and Mechanical Robustness of Flexible Perovskite Solar Cells by Using HPbI₃ Additive

Abstract

High efficiency and mechanical stability are in great demand for commercial applications of the flexible perovskite solar cells (PSCs) in portable and wearable electronics. Herein, power conversion efficiency (PCE) and mechanical robustness of the methylammonium (MA)‐free flexible PSCs are simultaneously enhanced by incorporating a HPbI3 additive with optimal content in the perovskite precursor solution. The HPbI3 additive facilitates an improved morphology and crystallinity, as well as a decreased work function of the perovskite films, leading to improved device performance. As a result, PCEs of 20.1% and 18.74% are obtained for the rigid and flexible PSCs, respectively, which are among the best results for inverted MA‐free PSCs. The flexible PSCs maintain 95% and 70% of the initial PCE value after 1000 and 5000 bending cycles, respectively, at a bending radius of 4 mm. The current result reveals that using the HPbI3 additive is a universal strategy to enhance performance of the flexible PSCs effectively and promote the development of the perovskite‐based photovoltaics.

Solution-Processed SnO2 Quantum Dots for the Electron Transport Layer of Flexible and Printed Perovskite Solar Cells

“…As for the device’s Voc, there is almost a linear decay trend with the increase in the number of bending cycles. This indicates the formation of many defects (microcracks) in the perovskite layer, which increases the rate of charge carrier recombination in the layer and leads to a corresponding decrease in the Voc and Jsc values of the devices [ 78 , 79 , 80 , 81 ]. These trends in the behavior of the Jsc, FF, and Voc during the bending test result in a fast decay of the device’s PCE after the first 10 bending cycles (a decrease from 7% to 2.5%) and a slower decay between the 10th and 50th bending cycles.…”

The disappearing additive: introducing volatile ethyl acetate into a perovskite precursor for fabricating high efficiency stable devices in open air

“…This implies that the higher cross-sectional quality of the EA-modified perovskite layer is also caused by the EA additive and this better morphology could lead to higher performance (voltage) and stability of devices. 27,28 In order to confirm the conjecture that the Lewis base nature of EA can form strong chemical bonding interactions with perovskite to passivate the defects during crystallization, the Fourier Transform infrared spectroscopy (FT-IR) on the samples was performed. As exhibited in Fig.…”

“…This implies that the higher cross-sectional quality of the EA-modified perovskite layer is also caused by the EA additive and this better morphology could lead to higher performance (voltage) and stability of devices. 27,28…”

Flexible Perovskite Solar Cells with High Power-Per-Weight: Progress, Application, and Perspectives

“…Meanwhile the formed soft fullerene network around the perovskite grains lead to a significantly improved mechanical stability. Recently, Jiang et al 82 incorporated a HPbI 3 additive into the perovskite precursor solution, facilitating improved crystallinity and decreased work function for the perovskite films. The resultant MA-free flexible PSCs with inverted structure reached to a 18.74% PCE, and maintained 95% of the initial PCE after 1000 bending cycles at a bending radius of 4 mm.…”