Approach To Enhance the Stability and Efficiency of Triple-Cation Perovskite Solar Cells by Reactive Antisolvents

Abstract

Controlling thin-film crystallization kinetics of perovskites is vital for the fabrication of highly efficient and stable perovskite solar cells (PSCs). Because of the low solubility of lead halogen derivatives in dimethylformamide solvent and poor film quality, addition of dimethylsulfoxide (DMSO) to the solution as a cosolvent has a great effect on the crystallization kinetics and morphology of perovskite thin films. However, Pb-DMSO and residual DMSO complexes that are difficult to be removed from the structure can lead to structural deformations and stability issues. Here, two different reagents such as benzyl chloride (BCl) and benzyl bromide (BBr) are applied as antisolvents to eliminate these problems utilizing the Kornblum oxidation reactions in the triple-cation perovskite thin films formed by the one-step coating method. Electrochemical impedance spectroscopy (EIS) analysis has been carried out to explain the charge transfer resistances and capacitive behaviors under illuminated conditions. EIS measurements show that washing with BBr antisolvent reduces the charge recombination in PSCs and leads to the best device performance with improved charge transport, yielding a 19.2% power conversion efficiency with a higher open circuit voltage (V oc ) of 1100 mV compared to washing with chlorobenzene (CB) and BCl. Resistances at the low-frequency region in Nyquist complex plots associated with charge recombination resistances were measured to be 1430, 564, and 3000 ohm, which are in good agreement with short circuit currents 23.3, 23.1, and 24.8 mA/cm 2 for devices fabricated with CB, BCl, and BBr, respectively. Removal of the residual DMSO and Pb-DMSO complexes via washing with BBr results in achieving more stable and highly efficient solar cells, which maintained 94% of the initial efficiency after 1 month.

Efficient and stable formamidinium–caesium perovskite solar cells and modules from lead acetate-based precursors

“…[26][27][28][29] The addition of these solvents has been found to be detrimental to the device stability as they can easily be trapped in the films and lead to the formation of voids at the perovskite substrate interface due to their high boiling points and strong coordination ability. [30][31][32][33][34] Although, there is still an ongoing debate in the literature on the impact of these voids with a recent study suggesting that they are not necessarily detrimental to the device stability. 35 By using PbAc 2 as the lead source these problems can be avoided as neither an antisolvent nor the addition of a high-boiling point solvent, such as DMSO or NMP, is required to control the crystallization.…”

Decreased surface defects and non-radiative recombination via the passivation of the halide perovskite film by 2-thiophenecarboxylic acid in triple-cation perovskite solar cells

“…Organic-inorganic lead halide perovskite solar cells (PSCs) have attracted great interest because of their significant optoelectronic properties besides the ease of production and lowcost fabrication techniques. [1][2][3][4][5] In the last decade, the power conversion efficiency (PCE) of organic-inorganic lead halide PSCs have jumped remarkably from 3.9% 1 to 25.5% 6 due to enhancements of the materials, 7 solvents/antisolvents, 8,9 and engineering of the interfaces. 10,11 To achieve well-performed PSCs, the passivation of defects, elimination of the energy level mismatch at the interface, the improvement of the absorber film quality is the key parameter.…”

Superior External Quantum Efficiency of LEDs via Quasi-2D Perovskite Crystals Implanted with Phenethylammonium Acetate

“…For the classical thin film, τ 1 remains unchanged while τ 2 and τ 3 decrease with the laser intensity. In principle, τ 1 , τ 2 , and τ 3 correspond to the defect-assisted recombination, bimolecular (electron–hole pair) recombination, and radiative recombination of free carriers, respectively. , This means that the defect-assisted recombination remains unchanged, while the bimolecular recombination and free carrier recombination are suppressed at high laser intensity. This is because the defect density cannot significantly change by the laser intensity in short-term irradiation.…”