Thickness control and photovoltaic properties of CH₃NH₃PbI₃ bar-coated thin film

Abstract

Thin films of a typical organic–inorganic halide perovskite material, CH3NH3PbI3 (MAPbI3), were fabricated by a bar-coating method, which is one of the candidate techniques for large-scale production. The film thickness of MAPbI3 markedly changed depending on the sweep speed of the coating bar, that is, it decreased in evaporation regime under the low-speed condition, and increased in the Landau–Levich regime under the high-speed condition. The typical inverted-type p-i-n planar solar cells with the MAPbI3 thin films demonstrated the photoelectric conversion efficiency of 14.0%, and their photovoltaic properties depending on the sweep speed were discussed by taking the surface morphology and crystallinity into consideration.

Perovskite solar cell fabrication via scalable thermal‐assisted and meniscus‐guided bar‐coating method in open air

“…Fast solvent evaporation at a temperature near the boiling point and a relatively lower coating speed in the ‘evaporation regime’ facilitate rapid crystal nucleation and growth. Thus, compact and larger perovskite crystalline grains can be formed without extra processes such as gas blowing, vacuum quenching, and anti‐solvent dripping [33, 36]. Recently, we also reported a thermal‐assisted and meniscus‐guided process in forming large‐area perovskite film through the solution‐shearing process using a blade, from which uniform and high‐quality perovskite film with oriented and large crystalline grains were achieved, and excellent film properties and solar cell efficiency were demonstrated [37, 38].…”

“…The simple cylindrical bar structure offers accurate control of the gap with the substrate to achieve a uniform film and the process is also compatible with the R2R process [40,41]. Up to date, only a few works were reported for perovskite film fabrication by the bar-coating method [36,39,[42][43][44][45][46]. These experimental reports mainly focused on the precursor solution engineering for rapid film fabrication, and additional air-knife blowing was applied to facilitate the perovskite crystallization.…”

2D/3D perovskite heterostructure solar cell with orientation-controlled Dion–Jacobson 2D phase

“…35) The first bar-coating fabricated the 3D perovskite layers of MAPbI 2 Br and MAPbI 3 . 37,38) Judging from the XRD patterns in Fig. S1, the crystal orientation [110] of MAPbI 2 Br was vertically oriented to the substrate surface, whereas the [200]/ [112] of MAPbI 3 was vertically oriented.…”

Orientation Control of 2D Perovskite in 2D/3D Heterostructure by Templated Growth on 3D Perovskite

“…In this study, “the dual bar-coating method”, the schematic illustration of which is shown in Figure , was introduced to fabricate 2D/3D perovskite heterostructures. The MAPbI 3 precursor solution was spread on the substrate by the first coating, then the liquid thin film of the precursor solution was converted to 3D perovskite thin film by the subsequent annealing process . The solvent of precursor and stoichiometric ratio of precursor dominate the crystallographic orientation of 3D perovskite.…”

“…The MAPbI 3 precursor solution was spread on the substrate by the first coating, then the liquid thin film of the precursor solution was converted to 3D perovskite thin film by the subsequent annealing process. 36 The solvent of precursor and stoichiometric ratio of precursor dominate the crystallographic orientation of 3D perovskite. For example, the use of dimethyl sulfoxide (DMSO) as a solvent of MAPbI 3 precursor allows (200)/(112)-oriented MAPbI 3 , 37−39 which can be actually confirmed in the GIWAXS image of Figure S1a.…”