Hybrid Lead Halide Perovskite Films with Large Grain Size Via Spin‐Coating Free Fabrication

Abstract

Herein, a spin‐coating‐free method to deposit CH3NH3PbI3 perovskite films with large grains is demonstrated. The effect of processing temperature on the property of hybrid lead halide perovskite films is investigated. It is found that the grain domain size is enlarged by increasing processing temperature. Dense and uniform CH3NH3PbI3 films with grain domain size close to 1 mm are obtained using this method. A higher processing temperature also promotes the conversion from precursors solution to perovskite, but excessive temperature induces a poor crystalline state. About 150 °C is proved to be close to the optimal processing temperature to form perovskite films with less defect density, lower charge recombination, and longer charge carrier lifetimes. Space‐charge‐limited current method is used to investigate the charge transport efficiency based on CH3NH3PbI3 perovskite films. The results show that both the electron and hole mobility improve remarkably as the processing temperature increases.

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“…The hole mobilities were calculated by fitting the resulting curves to a space-charge-limited form where SCLC can be described by: where ε 0 is the permittivity of free space (8.85 × 10 −12 F m −1 ), ε r is the relative dielectric constant of the conjugated polymers (typically assumed as 3), μ h is the hole mobility, L is the film thickness of active layer, and β is the field-dependent factor, V bi is the built-in potential due to the WF difference of electrodes caused by contact resistance and series resistance across the electrodes. 41 …”

“…where 3 0 is the permittivity of free space (8.85 Â 10 À12 F m À1 ), 3 r is the relative dielectric constant of the conjugated polymers (typically assumed as 3), m h is the hole mobility, L is the lm thickness of active layer, and b is the eld-dependent factor, V bi is the builtin potential due to the WF difference of electrodes caused by contact resistance and series resistance across the electrodes. 41 AFM images were obtained using Veeco Dimension 3100 instrument working at tapping mode.…”