Enhanced performance of carbon-based CsPbI2Br perovskite solar cells using interfacial modifiers
Carbon-based CsPbI2Br perovskite solar cells (C-PSCs) have attracted significant attention as promising candidates for solar energy conversion due to their optimal bandgap, stability, and ease of fabrication. However, surface and grain boundary defects in CsPbI2Br contribute to significant non-radiative recombination and energy loss, while the energy level mismatch between the carbon electrode and CsPbI2Br exacerbates open-circuit voltage (Voc) loss, limiting photovoltaic performance. To address these challenges, 3-(trifluoromethyl)phenylthiourea (3-TPT) and 4-(trifluoromethyl)phenylthiourea (4-TPT) were introduced as interfacial modifiers. The functional groups in 3-TPT and 4-TPT, including CS, –CF3, and –NH2, effectively passivated cationic and anionic defects, reducing defect density and suppressing non-radiative recombination. Additionally, isopropyl alcohol (IPA) solutions of 3-TPT and 4-TPT promoted secondary crystallization and grain reorganization, resulting in larger grains and denser boundaries, which significantly enhanced the CsPbI2Br crystal quality. Furthermore, 3-TPT and 4-TPT modulated the band structure of CsPbI2Br, improving the energy level alignment with the carbon electrode and minimizing energy loss. The power conversion efficiencies (PCEs) of C-PSCs modified with 3-TPT and 4-TPT reached 13.78% and 14.15%, respectively, compared to 12.18% for the unmodified device. The –CF3 groups in 3-TPT and 4-TPT enhanced the hydrophobicity of CsPbI2Br, effectively mitigating moisture ingress. After 500 h in a humid environment (30% relative humidity), the modified devices retained 81.8% and 85.7% of their initial PCE, significantly outperforming the 50.6% retention of the unmodified device. This study demonstrates a simple and effective approach to improving both the efficiency and long-term stability of carbon-based CsPbI2Br solar cells.
危险品化学品经营许可证（带存储）