While hybrid perovskites have great potential as light-absorbing materials, they suffer from moisture-induced instability. Herein, we added the amino acid iodide salt-based molecular crosslinker p-aminobenzoic acid (PABA∙HI) to a perovskite precursor solution to enhance the humidity stability. The rigid molecular structure of PABA∙HI played an important role in determining the crystal orientation, trap density, and photovoltaic performance of the perovskite solar cells (PVSCs). PABA∙HI can effectively interact with the Pb-I framework via hydrogen bonds, enhancing the crosslinking efficiency compared with freely rotating flexible molecular crosslinkers. Kelvin probe force microscopy in conjunction with Raman analysis confirmed the presence of PABA∙HI at the grain boundaries; thus, stable quasi-two-dimensional perovskite existed along the grain boundaries, passivating the grain boundaries and improving the moisture stability. The PABA∙HI-added PVSCs having a power-conversion efficiency (PCE) of 17.4% retained 91% of their initial PCE when stored for 312 h at a relative humidity of 75% at 25 °C, whereas a pristine cell with a PCE of 16.4% only retained 37% of its initial value. Our findings clearly indicate that the amino acid salt as a rigid molecular crosslinker improved not only the photovoltaic performance but also the stability against moisture.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation (NRF) of Korea grant (No. 2012R1A3A2026417) funded by the Ministry of Science and ICT.
This work was supported by the National Research Foundation (NRF) of Korea grant (No. 2012R1A3A2026417 ) funded by the Ministry of Science and ICT.
© 2019 Elsevier Ltd
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Electrical and Electronic Engineering