سنتز و كاربرد مواد اصلاح كننده سطح پروسكايت بر پايه متيلن فلورن و كربازول در سيستم هاي اپتوالكترونيك

Synthesis an‎d Application of Perovskite Surface Passiviation Based on Methylenefluorene an‎d Carbazole in Optoelectronic Devices

شيمي آلي و پليمر

Abstract Study 1: The upper surface of the perovskite layer in conventional solar cells contains defects an‎d traps that significantly limit the cellʹs efficiency an‎d stability. In the first part of this thesis, we design small organic molecules that serve as an interfacial layer between the Spiro-OMeTAD hole transport layer an‎d the perovskite layer. The goal is to reduce surface defects of the perovskite layer, thereby enhancing charge carrier transport an‎d stability. In this study, three small organic molecules with different side groups were synthesized to improve interactions with the perovskite layer. Results show that the molecule 9-(dichloromethylene)-N7,N7,N2,N2-(tetraxis(4-methoxyphenyl)-9H-fluorene-7,2-diamine), abbreviated as TPA-Cl, due to the low electronegativity of chlorine an‎d the spatial congestion in the structure, causes degradation of the perovskite layer. The application of 2-(2,7-bis(bis(4-methoxyphenyl)amino)-9H-fluorene-9-ylidene)malononitrile, also abbreviated as TPA-Cl, similarly led to degradation an‎d reduced hole collection efficiency. However, the molecule 2,7-bis(bis(4-methoxyphenyl)amino)-9H-fluorene-9-one (TPA-O), containing a carbonyl side group, not only enhanced charge carrier collection efficiency but also significantly reduced surface defect passivation. Implementing this structure in perovskite solar cells achieved a power conversion efficiency (PCE) of 23.25%, retaining 88.5% of its initial performance after 2,544 hours under ambient conditions. This architecture also demonstrated a PCE of 21.81% in flexible cells, with commendable mechanical stability. These findings open new avenues for improving the efficiency an‎d durability of perovskite solar cells. Study 2: One distinctive feature of organic hole transport semiconductors is their high carrier mobility an‎d ability to passivate shallow surface defects in the perovskite layer. This behavior plays a crucial role in enhancing the performance an‎d stability of optoelectronic systems based on perovskites, including quantum-dot-based perovskite light-emitting diodes (LEDs) an‎d solar cells. In this study, two small organic hole-transport molecules Tris(4-(6,3-bis(methylthio)-9H-carbazole-9-yl)phenyl)amine (X15) an‎d Tris (4-(7,2-bis(methylthio)-9H-carbazole-9-yl)phenyl)amine (X13) were synthesized using methylthio groups as defect passivation centers to create more effective interactions with the perovskite layer in quantum-dot LED configurations. The results show that X15, due to the placement of methylthio groups at the para position relative to the carbazole core, displayed stronger interaction with the perovskite layer an‎d more efficient passivation of shallow surface defects. The quantum-dot perovskite LED containing X15 achieved an external quantum efficiency (EQE) of 22.89% on a small scale (0.09 cm²) an‎d 21.10% on a large scale (1 cm²). These devices performed better than those based on the conventional hole transport material poly(bis(4-phenyl)(6,4,2-trimethylphenyl)amine) (PTAA), which showed an EQE of only 15.03%.

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پروفسور بوژو -دانشگاه نانجينگ چين

156376