Abstract
The surface composition and morphology of FA0.85MA0.15Pb(I0.85Br0.15)3 films fabricated by the spin-coating method with different concentrations of NH2-POSS were investigated with atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), angle-resolved X-ray photoelectron spectroscopy (AR-XPS), and Fourier transform infrared spectroscopy (FTIR). It was found that the surface composition of the FA0.85MA0.15Pb(I0.85Br0.15)3 films was changed regularly through the interaction between NH2-POSS and the perovskite film. The corresponding surface morphological changes were also observed. When the concentration of NH2-POSS exceeded 10 mg/mL, a lot of cracks on the surface of the perovskite film were observed and the surface morphology was damaged. The surface composition and its distribution can be adjusted by changing the concentration of NH2-POSS and the proper concentration of NH2-POSS can substantially improve the quality of perovskite film.
Highlights
Hybrid organic-inorganic perovskite (HOIP) semiconductors have attracted a lot of intensive interest recently owing to their excellent advantages, such as a large absorption coefficient, long charge carrier diffusion lengths, and distinguished optoelectronic properties [1,2,3,4,5,6,7,8]
It is known that the stability of perovskite films is poor in wet environments, which leads to a decrease of the efficiency decrease or even failure of perovskite solar cells (PSCs)
Surface modification is one of the effective methods to improve the performance of organic-inorganic hybrid perovskite devices
Summary
Hybrid organic-inorganic perovskite (HOIP) semiconductors have attracted a lot of intensive interest recently owing to their excellent advantages, such as a large absorption coefficient, long charge carrier diffusion lengths, and distinguished optoelectronic properties [1,2,3,4,5,6,7,8]. Surface modification (e.g., metal ion doping and modification of common chemical additives) is one of the effective methods to improve the performance of organic-inorganic hybrid perovskite devices. Zhou et al explored an effective approach for simultaneous passivation of cation and anion vacancy defects in perovskite materials by adding NaF and achieved a power conversion efficiency of 21.46% [16]. Seok et al demonstrated that the introduction of additional iodide ions into the organic cation solution can reduce the concentration of deep defects and achieved a power conversion efficiency of 22.1% [18]. Because the FA0.85 MA0.15 Pb(I0.85 Br0.15 ) polycrystalline film has obvious defects at the grain boundaries, Chen et al reported that the NH2 -POSS passivation at the surface and grain boundaries of perovskite film can significantly reduce the trap density and trap state energy level, which in turn enhances the PCE from 18.1% to 20.5% [27]. The surface uniformity of the perovskite film is damaged when the concentration of NH2 -POSS is above 10 mg/mL
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