Subcategory: STEM Research
Qilin Dai - Jackson State University
Co-Author(s): Qiqi Zhang Jackson State University Jackson MS; Bo Li Jackson State University Jackson MS; Dream Box Jackson State University Jackson MS; James Tatum Jackson State University Jackson MS
TiO2 electron transport layers have been commonly used in perovskite solar cells (PSCs) since the high electron extraction efficiency of TiO2, leading to high efficiency of PSCs. In this work, flower-shaped titanium dioxide (TiO2) layers were obtained by the combination of chemical bath deposition (CBD) and dip-coating post-treatment methods, which were further used as electron transport layer (ETL) and scaffold for perovskite solar cells (PSCs). TiO2 ETL was prepared by the combination of chemical bath deposition (CBD) and dip-coating post-treatment in 400 mM TiCl4 DI-water solution, followed by low-temperature annealing at 200? for 30 min. We fabricated perovskite solar cells based on TiO2 ETLs with and without dip-coating post-treatment, the device architecture is FTO/TiO2/CH3NH3PbI3 (MAPbI3)/spiro-OMeTAD/Au. In the case of PSCs based on CBD-TiO2, the compact TiO2 layer adhere strongly to rough FTO surface with a thickness of ~100 nm, while the flower-shaped TiO2 aggregates can be clearly observed at the bottom and middle of perovskite film, in turn acts as scaffolds in the architecture to improve electron extraction efficiency. The highest PCE of 16.2% was obtained for PSCs based on CBD-TiO2, and showed an open voltage (Voc) of 1.11 V, short-circuit current density (Jsc) of 20.96 mA/cm2, and fill factor (FF) of 71.3%. Owing to enhanced Jsc and FF, the improved PCE of 20.02% was achieved for PSCs based on dip-coating post-treated TiO2, which should be attributed to the enhanced electron extraction efficiency. In addition, we also observed the reduced hysteresis effect in reverse and forward J-V scans, the hysteresis index is 31.8% and 6.1% for PSCs with and without dip-coating post-treatment, respectively.
Funder Acknowledgement(s): This work was supported by NSF HBCU-UP Research Initiation Award: Novel Perovskite Solar Cells Based on Interface Manipulation (#1900047)
Faculty Advisor: None Listed,
NSF Affiliation: HBCU-UP