Improved Open-Circuit Voltage and Repeatability of Perovskite Cells Based on Double-Layer Lead Halide Precursors Fabricated by a Vapor-Assisted Method

Abstract

Highly repeatable fabrication of compact perovskite films is crucial for large-area perovskite cells (PSCs) in commercial applications. In this work, a vapor-assisted method with the combination of spin-coating and thermal evaporation is employed to fabricate the double-layer PbI 2 /PbI x Br (2−x) precursor. It is found that surface morphologies of perovskite films could be tailored through tuning the spin-coating speed (the first precursor layer) and chemical compositions (the second precursor layer). The continuous pinhole-free perovskite films are successfully fabricated by double-layer PbI 2 /PbBr 2 precursors. The open-circuit voltages of all the corresponding cells exceed 1.00 V, showing an average value of 1.02 V. The high mean voltage and small variation reveals high repeatability of this method. This work provides a potential method to achieve large-area and high-efficiency PSCs.

Precursor Engineering of Vapor-Exchange Processes for 20%-Efficient 1 cm2 Inverted-Structure Perovskite Solar Cells

“…Among all preparation methods of perovskite, vapor-involved methods offer a very high reproducibility . They can produce a large-area (1–2 cm 2 ) cell with almost the same efficiency as the small-area ones, − and are easy to prepare a stack structure. − In 2014, Yang et al developed a vapor-assisted solution process (VASP) method for preparing PSC .…”