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

Abstract

In recent years, organic–inorganic halide perovskite solar cells (PSCs) have attracted massive attention because of its high power conversion efficiency (PCE). However, it’s difficult for preparation of perovskite film with...

Enhancing Photovoltaic Performance through Optimized Antisolvent Strategy for Low-Bandgap Pb–Sn Perovskites

“…Importantly, the crystallization degree of Pb–Sn perovskites was susceptible to the EA volume ratios, as evidenced by the appearance of the uncoordinated PbI 2 /SnI 2 peak at 12.6°. The uncoordinated peak resulted from incomplete crystallization, perovskite decomposition, or defect presence. − Interestingly, only the perovskite film processed with EA25 antisolvent did not exhibit the discernible PbI 2 /SnI 2 peak at 12.6°, as depicted in the magnified portion of Figure a. This implies that EA25 antisolvent did facilitate the phase transformation from a liquid precursor solution to a solid perovskite structure devoid of decomposition and defects.…”

Crystallization Kinetics of Perovskite Films by a Green Mixture Antisolvent for Efficient NiOx-Based Inverted Solar Cells

“…The EA/ IPA-based perovskite thin film shows the highest PL intensity, indicating a longer carrier lifetime than the pure EA and pure IPA perovskite thin films (Figure 6e). 5,6,39 The TRPL curves are fitted by the biexponential decay function of f(t) = A 1 exp(−t/τ 1 ) + A 2 exp(−t/τ 2 ) + f 0 . The τ 1 and τ 2 values are dominated by carrier transfer at the perovskite−PTAA interface and radiative recombination of trapped charges from the bulk perovskite, respectively.…”

“…The trap-filled limit voltage ( V TFL ) values of these three devices with the EA-, EA/IPA-, and IPA-based devices are 0.725, 0.586, and 0.785 V, respectively. The defect density ( N t ) could be calculated according to the equation N t = 2 V TFL εε 0 )/( qL 2 ), where q is the charge of an electron, L is the thickness of the perovskite thin film, ε and ε 0 are the relative dielectric constants of perovskite and the vacuum dielectric constant, respectively. ,, N t of the perovskite thin film with an EA/IPA (5:1) antisolvent is 7.8 × 10 15 cm –3 , which is lower than pure EA and pure IPA samples. To understand the charge recombination and transport in the devices, we conducted transient photovoltage (TPV) measurements.…”

“…56 Figure 6a shows the dark J−V curves of the PSCs. The EA/ IPA-based PSC exhibits the smallest reverse saturation current where n, k B , T, q, and I denote the ideality factor, Boltzmann constant, absolute temperature, elementary charge, and light density, 32,35,39 respectively. The n values for EA-, EA/IPA-, and IPA-based devices are 1.12, 1.10, and 1.37, respectively, indicating that the EA/IPA-based perovskite effectively inhibits the trap-assistant charge recombination.…”

“…Green solvents such as ethanol (EtOH), , isopropanol (IPA), − sec -butyl alcohol (sBuOH), ethyl acetate (EA), ,− methyl benzoate (MB), sec -butyl acetate (sBA), and anisole (ANS) , have been used as the additive (or cosolvent) for the environmentally harmless antisolvent or as antisolvent alone in preparation of PSCs with still a slightly lower PCE. Different antisolvents might lead to different initial nucleation and following growths and ripening during the crystallization due to their different physical and chemical properties, including the boiling point, dipole moment, viscosity, surface tension, density, and so on, , which are related to the solubility, miscibility, and polarity.…”