Bifunctional Passivation through Fluoride Treatment for Highly Efficient and Stable Perovskite Solar Cells

Abstract

Due to the low formation energy, surface defects are more likely to form on the surface of TiO2 films, resulting in a decline in the efficiency and stability of perovskite solar cells (PSCs). Additionally, defects on the bottom surface of the perovskite layer in contact with TiO2 play a key role in Voc (open circuit voltage) loss and the PSC degradation process. Therefore, to improve the efficiency and stability of PSCs, it is critical to develop a reproducible and low‐cost method for passivating the defects on both the TiO2 surface and on the bottom surface of the perovskite layer. In this work, fluoride is utilized as a bifacial contact passivation agent for decreasing the number of defects on the TiO2 surface and the bottom surface of the perovskite layer. PSC efficiency can be significantly increased from 21.3% to 23.7% with fluoride passivation. In addition, the long‐term stability of PSCs, especially light irradiation stability, can be markedly improved. The passivation effects of fluoride treatment on TiO2 films are studied by theoretical calculation and experimental characterization. This work provides a thorough understanding of the TiO2/perovskite interface and demonstrates an approach for improving the efficiency and stability of PSCs.

Multifunctional Passivator Trifluoroacetamidine for Improving the Performance of All‐Inorganic CsPbI3 Perovskite Solar Cells

“…In order to further reveal the impact from TFA on CsPbI 3 films, X-Ray photoelectron spectroscopy was conducted. [36] As shown in Figure 2c,d, the peaks of Pb 4f and I 3d5 of control film are, respectively, located at 142.97 and 618.95 eV. With the incorporation of 0.3 mol% TFA, the peaks of both Pb 4f and I 3d are shifted to lower binding energy positions, which further confirms the interaction between perovskite film and TFA.…”

Modulation of nucleation and crystallization in PbI2 films promoting preferential perovskite orientation growth for efficient solar cells

“…Specifically, formamidinium-rich lead iodide (FAPbI 3 ) is of interest to light absorbers because its narrow bandgap is close to the Shockley-Queisser optimum. [2][3][4][5][6][7][8][9] FAPbI 3 -based PSCs deliver extremely efficient PCEs, and their perovskite absorbers are generally prepared by a one-step antisolvent or a two-step sequential deposition method. [10][11][12][13][14][15][16] In particular, the two-step approach has excellent operability and vast potential for commercialization, thanks to the possibility of prior regulation of the lead iodide (PbI 2 ) templates.…”

24.20%‐Efficiency MA‐Free Perovskite Solar Cells Enabled by Siloxane Derivative Interface Engineering

“…To probe the effect of PSiOH modification on the charge transfer process at the interface of TiO 2 and FA 0.83 Cs 0.17 PbI 3 films, the steady-state photoluminescence (PL) and timeresolved PL (TRPL) decay measurements are carried out. [29] As shown in Figure 2c, the PL intensity of FA 0.83 Cs 0.17 PbI 3 perovskite is obviously quenched after PSiOH modification, reaching a minimum at a modification concentration of 1.50 mg mL -1 and indicating that PSiOH modification is conductive to charge extraction at the interface. [30] The TRPL spectra are fitted by a double-exponential decay function and the fitting parameters are summarized in Table S1 (Supporting Information).…”