Understanding the solvent-assisted crystallization mechanism inherent in efficient organic–inorganic halide perovskite solar cells

Abstract

N,N-Dimethylformamide (DMF) has been shown to be an efficient precursor solvent for the one-step deposition of perovskite thin films in photovoltaic applications. Here, the specific advantage DMF introduces during the perovskite crystallization process is elucidated through comparison with dimethylacetamide (DMAc), one of its homologues. The unique presence of a DMF-induced intermediate phase was verified for the first time and its positive functions to inhibit uncontrolled perovskite precipitation and facilitate homogeneous nucleation were demonstrated. When combined with a double blocking layer structure to prevent shunting, our planar heterojunction (PHJ) perovskite solar cells achieved a high power conversion efficiency of up to 13.8%. Our results uncover the origin of the widespread adoption of DMF in perovskite thin film deposition, and represent a helpful step towards judicious perovskite morphological control.

New insight into solvent engineering technology from evolution of intermediates via one-step spin-coating approach

“…4a) appear at P-100 intermediate phases. According to previous reports, the lower angle of intermediate phases indicates that MAI and DMSO molecules have intercalated into the PbI2 layered structure [18]. Based on the Bragg formulation, XRD peak of PbI2 (Fig.…”

“…Previous studies have uncovered that full surface coverage and low surface roughness are crucial for governing the device photovoltaic performance [5,6]. Therefore, to prepare high quality perovskite thin films, various methods have been developed, e.g., vacuum evaporation [6], vapor-assisted deposition [13][14][15], solvent engineering [16,17] and solution-based techniques [18][19][20]. Among these methods, solvent engineering technology has proven to be an efficient way for producing dense perovskite layers in a one-step deposition.…”

Nanoconfined Crystallization of MAPbI3 to Probe Crystal Evolution and Stability

“…17 Shen and coworkers also identified the presence of a crystalline PbI 2 :DMF complex prior to the formation of perovskite crystals on fluorinated tin oxide-coated glass surfaces. 19 Detailed structural characterization of these intermediate phases, however, was not reported. Nanoconfinement of perovskite crystallization in mesoporous scaffolds likely plays a role in guiding the crystallization process during PSC fabrication.…”

Hybrid Perovskites: Effective Crystal Growth for Optoelectronic Applications

“…(Table 3 Figure 9a). [144] Solid (Figures 9b-c). [109,175] Solar cell devices demonstrate highly reproducible performances with the best PCE of 19.7 %.…”