image: In this work, a self-assembled material was proposed as a hole-selective contact for Sn-Pb perovskite solar cells. The molecule's large dipole moment enhanced hole extraction at the buried interface, achieving a highly power conversion efficiency of 23.45%. Remarkably, It addressed the interfacial chemical instability induced by PEDOT:PSS, thereby enhancing the devices’ storage life.
Credit: ©Science China Press
This study is led by Prof. Meng Li (Key Lab for Special Functional Materials of Ministry of Education, School of Nanoscience and Materials Engineering, Henan University). Both experiments including device preparation, photoelectric property characterizations and performance evaluation and DFT calculations were performed.
The hybrid Sn-Pb perovskite benefits from its narrow bandgap characteristics, showing great potential in the manufacturing of high-efficiency single-junction solar cells and all-perovskite tandem solar cells. However, the commonly used hole transport materials in Sn-Pb perovskite devices can lead to energy level mismatches at the perovskite device interfaces or cause degradation at the buried interface of the Sn-Pb perovskite, limiting the development of high efficiency and stability in Sn-Pb perovskite devices. Designing a simple and reliable hole-selective material is crucial for ensuring efficient charge extraction at the interface and the long-term stability of the Sn-Pb devices.
To address these challenges, the research team led by Prof. Li Meng from Henan University has designed a self-assembled material, 4-(9H-carbazole-9-yl)phenylboronic acid (4PBA), which served as a boronic acid-anchored hole-selective contact for the Sn-Pb perovskite. Compared to traditional SAM materials, 4PBA formed a low-corrosive and reliable anchoring on the substrate surface with an adsorption energy of −5.24 eV, and its substantial molecular dipole moment (4.524 D) facilitated energy level alignment between the substrate and the Sn-Pb perovskite layer, enhancing the charge extraction capability of the device. Additionally, the improved buried interface promoted better crystallization of the perovskite and enhanced the contact between the perovskite and the substrate, reducing traps and non-radiative recombination. As a result, Sn-Pb PSCs based on 4PBA achieved a high PCE of 23.45%. The independent use of 4PBA as a hole-selective contact can avoid acid-induced degradation of the Sn-Pb perovskite caused by PEDOT:PSS, and the enhanced chemical stability of the buried interface delayed the degradation process, the device have a better shelf storage stability with 93.5% retention of the initial efficiency after 2000 h.
This strategy provided insights for developing efficient and stable Sn-Pb perovskite solar cells with energy level matching and interface chemical stability.
See the article:
Buried Hole-Selective Interface Engineering for High-Efficiency Tin-Lead Perovskite Solar Cells with Enhanced Interfacial Chemical Stability
https://doi.org/10.1016/j.scib.2024.12.004
Journal
Science Bulletin