Tuning of perovskite solar cell performance via low-temperature brookite scaffolds surface modifications

Abstract

The nature of metal oxide scaffold played a pivotal role for the growth of high quality perovskites and subsequently facilitates efficient photovoltaics devices. We demonstrate an effective way to fabricate a low-temperature TiO2 brookite scaffold layer with a uniform and pinhole-free layer for enhancing photovoltaic properties of perovskite solar cells. Various concentrations of TiCl4 were used to modify brookite TiO2 for efficient charge generation and fast charge extraction. We observed that the brookite layer with an appropriate TiCl4 treatment possesses a smooth surface with full coverage of the substrates, whereas TiCl4 treatment further improves the contact of the TiO2/perovskite interface which facilitates charge extraction and drastically influenced charge recombination. The surface treated brookite scaffolds perovskite devices showed an improved performance with an average power conversion efficiency more than 17%. The time resolved photoluminescence showed that the treated samples have obvious effect on the charge carrier dynamics. The striking observation of this study was very low appearance of hysteresis and high reproducibility in the treated samples, which opens up the possibilities for the fabrication of high efficient devices at relatively low temperatures with negligible hysteresis via facile surface modifications.

Sulfate‐Assisted Interfacial Engineering for High Yield and Efficiency of Triple Cation Perovskite Solar Cells with Alkali‐Doped TiO2 Electron‐Transporting Layers

“…Thus ETLs should be pinhole free films, possess good adhesion with adjacent layers and high charge extraction capacity. The interface modifications of the TiO 2 ETL using amino acids, carboxyl groups, graphene, thiols and TiCl 4 have also shown improvements in the charge extraction process at the ETL/perovskite interface. Recently, metal oxide‐based thin films and mesoporous ETLs have been studied with the emphasis on improving charge collection, device stability and minimizing various recombination losses within the perovskite and at the adjacent interfaces .…”

Lead-free perovskite solar cells using Sb and Bi-based A3B2X9 and A3BX6 crystals with normal and inverse cell structures

“…This Bi-based organic-metal-halide solar cells were reported 0.33% of the low PCE, which was limited by its high exciton binding energy of 300 meV. It was founded that the morphology of (CH 3 NH 3 ) 3 Bi 2 I 9 was changed by the selection of electron transporting layers (ETL), and that the small amount addition of NMP ( N -methyl-2-pyrrolidone) solvent could also attain to grow uniform surface morphology [ 18 , 19 ].…”

Progress in Materials Development for Flexible Perovskite Solar Cells and Future Prospects

“…This new member of the photovoltaic cell family has created a sensation among the researchers in the past few years since its first report by Kojima et al [1] In this period of time, the record efficiency of PSCs has been increased from 3.8 % to 25.5 %. [1][2][3][4][5][6][7][8][9][10][11][12] Needless to say, high efficiency, low cost, and solution processability are major factors driving the increasing attention being paid to PSCs. Flexible perovskite solar cells (fPSCs) are prepared by low-temperature solution processing on lightweight, flexible substrates.…”