A low-temperature TiO2/SnO2 electron transport layer for high-performance planar perovskite solar cells

Conventional titanium oxide (TiO2) as an electron transport layer (ETL) in hybrid organic-inorganic perovskite solar cells (PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperatureprocessed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO2/tin oxide (SnO2) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO2/SnO2 ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO2/SnO2 bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO2 and Sn-2 single-layer ETL counterparts. The champion PSC has a power conversion efficiency (PCE) of 19.11% with an open-circuit voltage (V-oc) of 1.15 V, a short-circuit current density (k) of 22.77 mA cm(-2), and a fill factor (FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO2/SnO2 ETL in the device, a high V-oc, of 1.18 V is achieved. It has been proven that the TiO2/SnO2 bilayer is a promising alternative ETL for high efficiency PSCs

Electron-selective quinhydrone passivated back contact for high-efficiency silicon/organic heterojunction solar cells

Interfacial properties play a critical role in the dynamic process of carrier transport in dopant-free silicon (Si) heterojunction solar cells (HSCs), based on the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). In this study, we use quinhydrone (QHY) to engineer the interfacial properties by grafting the semiquinone (QH) on Si surface at low temperature. The QH monolayer provides effective chemical and fieldeffect passivation by the surface dangling-bond saturation and its interface dipole, respectively, and results in a large minority carrier lifetime of 477 mu s. At the front Si/PEDOT:PSS interface, the QH-terminated Si surface presents higher wettability for the improved contact at the Si/PEDOT:PSS junction. At the rear Al/Si interface, the work function of Al film is reduced significantly to form ohmic contact for electron-selective transport. The dark current-voltage and capacitance-voltage measurements show the improved electric characteristics with a higher carrier collection efficiency. Furthermore, the silicon band bending generated by the QH dipoles enhances the overall built-in potential of Si/PEDOT:PSS HSCs for a larger open-circuit voltage. As a result, the QHY modified Si/PEDOT:PSS HSC yields a power conversion efficiency of 13.29%. This approach demonstrates that the organic grafting is a simple, effective and low-cost method for the interface engineering to achieve high efficiency HSCs

Phosphate-Passivated SnO2 Electron Transport Layer for High-Performance Perovskite Solar Cells

Phosphate-Passivated SnO2 Electron Transport Layer for High-Performance Perovskite Solar Cell

Metal-Enhanced Adsorption of High-Density Polyelectrolyte Nucleation-Inducing Seed Layer for Highly Conductive Transparent Ultrathin Metal Films

Metal-Enhanced Adsorption of High-Density Polyelectrolyte Nucleation-Inducing Seed Layer for Highly Conductive Transparent Ultrathin Metal Film

Engineering of hole-selective contact for high-performance perovskite solar cell featuring silver back-electrode

Engineering of hole-selective contact for high-performance perovskite solar cell featuring silver back-electrod