Polyfluorene incorporation for superior performance and band gap reduction: enhancing Cs2AgBiBr6 double perovskite solar cells

• Published in: Journal of sol-gel science and technology 2024-12, Vol.112 (3), p.814-825
• Main Authors: Ullah, Asad, Rehman, Wasif ur, Khan, Muhammad Iftikhar, EL-Gawaad, N. S. Abd
• Format: Article
• Language: English
• Subjects: Ceramics; Chemistry and Materials Science; Composites; Crystal lattices; Efficiency; Electromagnetic absorption; Electron spin; Energy conversion efficiency; Energy gap; Glass; Grain size; Inorganic Chemistry; Lead free; Materials Science; Nanotechnology; Natural Materials; Open circuit voltage; Optical and Electronic Materials; Optical lattices; Original Paper; Perovskites; Photovoltaic cells; Refractivity; Short circuit currents; Sol-gel processes; Solar cells; Spin coating; Visible spectrum
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-024-06582-8

Lead-free halide double perovskites (LFHDPs) based on Cs 2 AgBiBr 6 are a good replacement for traditional lead-based LBPs due to their chemical stability and lack of toxicity. Double perovskite Cs 2 AgBiBr 6 -based solar cells have limited efficiency due to a large band gap, suggesting polyfluorene (PF) replacement as a workable solution to enhance their optical and photovoltaic characteristics. PF incorporation-induced crystal structural changes, as demonstrated by peak position shifts in X-ray diffraction. The UV–Vis spectroscopy, and solar simulator tests, were used to study the effect of PF on Cs 2 AgBiBr 6 . Optical examination reveals a decrease in E g , leading to improved light absorption in the visible spectrum. By adding PF to their lattices, we effectively give the weakly luminous Cs 2 AgBiBr 6 double perovskite robust red luminescence. The Cs 2 Ag 0.95 PF 0.05 BiBr 6 solar cell has demonstrated a notable enhancement in performance. In that order, its enhanced fill factor, short-circuit current, and open-circuit voltage are 0.81, 5.73 mA cm −2 , and 0.93 V. Power conversion efficiency (PCE) has improved from 3.75% to 4.26%. About 13.60% of efficiency is increased by PF incorporation. The study identifies Cs 2 Ag 0.95 PF 0.05 BiBr 6 as a high-performance material for solar applications and addresses issues with film formation. Our objective is to advance environmentally friendly solar technologies by enhancing efficiency, with future research focusing on interfacial engineering, specifically optimizing electron and hole transport layers. Graphical Abstract Highlights Pure and PF-doped Cs 2 AgBiBr 6 films have been prepared by sol–gel spin coating technique. XRD confirmed the doping and cubic phase of both films. PF-doped Cs 2 AgBiBr 6 contains large grain size, small E g and high refractive index. PF-Cs 2 AgBiBr 6 cell exhibits a high J sc of 5.73 mA cm 2 , V oc of 0.93 V, and achieved efficiency of 4.26%.