Comparison of surface-passivation ability of the BAI salt and its induced 2D perovskite for high-performance inverted perovskite solar cells

Abstract

A BAI layer was formed on the CH3NH3PbI3 surface, which was transformed into a 2D perovskite layer or the organic salt. Many measurements show that the 2D perovskite could effectively reduce the trap-assisted recombination and increase the stability.

Highly Efficient and Stable 2D Dion Jacobson/3D Perovskite Heterojunction Solar Cells

“…14,15 Many efforts have been devoted to increasing the PCE of 2D perovskites such as interface engineering, compositional engineering, solvent engineering, etc. 16,17 One such approach is to form a thin 2D layer on top of the 3D structure which can provide the dual benefit of higher efficiency from 3D perovskite and improved stability contributed by 2D analogue. 18,19 Consequently, 2D/3D heterostructure PSCs have recently received huge research interest with PCE reaching 24.35% for formamidinium lead triiodide based mixed perovskite (FAPbI 3 ) 0.95 (MAPbBr 3 ) 0.05 and stability 98% after 1620 h under full-sun illumination have been received.…”

“…Organic–inorganic hybrid perovskites have emerged as the most promising photovoltaic technologies due to their superior optoelectrical properties, including extended light absorption, long carrier diffusion length, large carrier mobility, low-temperature solution processability, and high defect tolerance. , The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has risen rapidly from the initial 3.8% to 25.5% within a decade. , However, the long-term operating stability of three-dimensional (3D) PSCs under outdoor conditions is still a matter of concern for their potential commercialization. − Recently, 2D perovskite with bulky organic cation in quantum well structure has been proven to show better thermal and moisture stability than their 3D counterpart. , Due to the inclusion of hydrophobic organic cation in the perovskite structure and large formation energy, these 2D perovskites can inhibit ion migration and minimize the defect states. − However, anisotropic charge transport in these 2D perovskites limits their PCE in comparison to 3D perovskite. , Many efforts have been devoted to increasing the PCE of 2D perovskites such as interface engineering, compositional engineering, solvent engineering, etc. , One such approach is to form a thin 2D layer on top of the 3D structure which can provide the dual benefit of higher efficiency from 3D perovskite and improved stability contributed by 2D analogue. , Consequently, 2D/3D heterostructure PSCs have recently received huge research interest with PCE reaching 24.35% for formamidinium lead triiodide based mixed perovskite (FAPbI 3 ) 0.95 (MAPbBr 3 ) 0.05 and stability 98% after 1620 h under full-sun illumination have been received . A wide variety of organic spacers with different structures, for example, butylammonium, n -propylammonium, 1,1,1-trifluoro-ethylammonium, ethylammonium, 2-(4-fluorophenyl)­ethylammonium, cyclopropyl ammonium, ammonium valeric acid, phenyl ethylammonium, and penta-fluorophenyl ethylammonium have been utilized to fabricate 2D/3D PSCs and improve the ambient stability. ,,− Most recently, Jeong et al have reported the facile fabrication of 2D/3D perovskite heterojunction by using cyclohexane ammonium iodide (CHAI) on the top of formamidinium lead triiodide (FAPbI 3 ) perovskites .…”

From Bulk to Surface Passivation: Double Role of Chlorine‐Doping for Boosting Efficiency of FAPbI3‐rich Perovskite Solar Cells

“…[7] Such LDP phases or, in a more simple configuration, only the large organic cations [8] can be incorporated either in the bulk of the active material or as a surface layer at the perovskite/ selective contact interfaces. [9][10][11][12] Most reports indicate that such a surface treatment chemically passivates the surface (filling under-coordinated lead atoms, vacancies, and other interfacial defects). [13,14] In this work, we combine the concepts of bulk passivation to reduce the bulk defect density, while improving Defect-mediated recombination losses limit the open-circuit voltage (V OC ) of perovskite solar cells (PSCs), negatively affecting the device's performance.…”

Visualizing interfacial defect passivation in carbon‐based perovskite solar cells

“…Perovskite precursor compositional engineering with chlorine‐based additives like Lewis base thiourea or urea, 8 pyridine, 9 Na + ions, 10 and excess lead in precursor 11 has been commonly used for surface defect passivation. Other passivation strategies involve introducing thin insulating layer of poly(methyl methacrylate) (PMMA), 12 PMMA:PCBM ([6,6]‐phenyl‐C61‐butyric acid methyl ester) blend, 13 two‐dimensional (2D) perovskite materials like phenethylammonium lead iodide ((PEA) 2 PbI 4 ), 14 butylammonium lead iodide (BA 2 PbI 4 ), 15 and octylammonium iodide 16 . These intermediate layers over the perovskite absorber layer have proven to passivate the surface and reduce interfacial recombination.…”