The Effects of Solvent on Doctor‐Bladed Perovskite Light Absorber under Ambient Process Condition for Multiple‐Cation Mixed Halide Perovskites
Kuo-Wei Huang, Prof. Ming-Hsien Li, Shih-Hsiung Wu, Pei-Ting Chiu, Jen-An Chen, Dr. Yu-Hung Chen, Dr. Chen-Fu Lin, Dr. Yung-Liang Tung, Prof. Peter Chen
Energy Technology, (2020)
Ambient processes, Cosolvent, Doctor blades, Perovskites, Solar cells
We demonstrate a doctor‐blading process for the fabrication of triple‐cation halide‐perovskite thin film using eco‐friendly solvent under ambient. An eco‐friendly perovskite precursor composed of γ‐butyrolactone (GBL)/dimethylsulfoxide (DMSO)/isopropanol (IPA) mixture is employed. The coordination between PbI2 and DMSO effectively suppresses the perovskite crystal grow rate which resulted in a dense and uniform film. However, the intermediate DMSO‐PbI2 phase residual has negative impact on the perovskite film quality. The amount of residues, the trap‐state defect density, the perovskite film uniformity and the device performance can be considerably affected by adding IPA in the precursor due to its capability to facilitate DMSO evaporation. After blading the perovskite film, heating post‐treatment on the top side of the film homogenizes the evaporation rate of the air‐liquid surface which leads to larger grain size and unbroken of perovskite film. The device employing perovskite solution with GBL/DMSO/IPA mixture as solvent achieves a decent power conversion efficiency (PCE) of 12.3% with a V oc of 1.01 V and a J sc of 19.3 mA/cm2. The bare device retains 76.5% of its original PCE after 25 days under ambient environment at 35˚C, with 35‐40% relative humidity. A large‐size device with an active area of 2.4 cm2delivered a PCE of 8.52%.