A Fast Deposition‐Crystallization Procedure for Highly Efficient Lead Iodide Perovskite Thin‐Film Solar Cells

Abstract

Thin-film photovoltaics based on alkylammonium lead iodide perovskite light absorbers have recently emerged as a promising low-cost solar energy harvesting technology. To date, the perovskite layer in these efficient solar cells has generally been fabricated by either vapor deposition or a two-step sequential deposition process. We report that flat, uniform thin films of this material can be deposited by a one-step, solvent-induced, fast crystallization method involving spin-coating of a DMF solution of CH3NH3PbI3 followed immediately by exposure to chlorobenzene to induce crystallization. Analysis of the devices and films revealed that the perovskite films consist of large crystalline grains with sizes up to microns. Planar heterojunction solar cells constructed with these solution-processed thin films yielded an average power conversion efficiency of 13.9±0.7% and a steady state efficiency of 13% under standard AM 1.5 conditions.

Hybrid Perovskites: Effective Crystal Growth for Optoelectronic Applications

“…Although spin-coating is an apparently simple and low cost deposition method, strong ionic interaction between metal cations and halogen anions commonly leads to the formation of inhomogeneous film morphology involved with poor surface coverage [106] , pillared structure [105] and non-uniform film thickness [99] .…”

“…Anti-solvents to perovskite such as toluene, chlorobenzene are dripped during the spinning of precursor solutions. [97,106] [14,38,107] Depending on the solvent used in the precursor solution, antisolvent and dripping timing should be carefully controlled for highly efficient optoelectronic devices.…”

Unreacted PbI2 as a Double-Edged Sword for Enhancing the Performance of Perovskite Solar Cells

“…During the second step, when approximately 15 seconds of the program remains, 100 µL of anhydrous chlorobenzene was applied on the spinning film with a hand held automatic pipette. This last step, known as the antisolvent method, has a large impact on film morphology and result in significantly better device performance [6][7][8] . It is, however, one of the steps that introduce a palpable degree of artisanship into the process.…”

Effects of Gas Blowing Condition on Formation of Perovskite Layer on Organic Scaffolds

“…Xiao et al improved the reproducibility by improving the surface coverage of the perovskite layer on the scaffolds. 21 Wakamiya et al reported the importance of dehydrate PbI 2 . 22 We concluded that low reliability might also occur because of these defects.…”