Suppression of Nonradiative Recombination by Vacuum‐Assisted Process for Efficient Lead‐Free Tin Perovskite Solar Cells

Abstract

Power conversion efficiency (PCE) of lead (Pb)‐free tin (Sn)‐based perovskite solar cells (PVSCs) is much lower than that of their Pb‐based counterparts, which is mainly attributed to large open‐circuit voltage (VOC) loss and poor fill factor (FF). In this work, a strategy via vacuum‐assisted treatment of the Sn perovskite layer to self‐heal defects in Sn perovskite is reported, leading to suppression of nonradiative recombination and enhancement of carrier transport capability. Using this method, a maximum PCE of 10.3% is obtained for dual FA‐MA (MA = methylammonium and FA = formamidinium) cation Sn‐based PVSCs with an improved VOC of 0.631 V and FF of 75.5%. This work suggests a facile approach to finely inhibit the defects in the bulk or at interfaces for Sn‐based devices and further facilitate development of highly efficient Sn‐based PVSCs.

Dopamine Hydrochloride-Assisted Synergistic Modulation of Perovskite Crystallization and Sn2+ Oxidation for Efficient and Stable Lead-free Solar Cells

“…Moreover, light-intensity-dependent V oc curves are measured to evaluate charge recombination losses (Figure c). V oc is determined by the equation where n id is the ideality factor related to charge carrier recombination, and J 0 and J ph are the saturated current density and photocurrent density, respectively. Compared to the control device, the DACl-derived TPSC shows a decrease in n id from 1.68 to 1.38.…”

Methylammonium and Bromide‐Free Tin‐Based Low Bandgap Perovskite Solar Cells

“…[127][128][129] Additives engineering especially with commonly used tin fluoride and interfacial engineering has shown superior properties in suppression of nonradiative recombination in lead-free PSCs. [130][131][132] First, interface functionalization effectively passes the interfacial defects and strengthens the perovskite surface. During the perovskite film fabrication, high-density levels defects are most likely present inside the bulk and on the surface of the resulting film.…”

Perovskite/Si tandem solar cells: Fundamentals, advances, challenges, and novel applications

“…Perovskite materials are considered to be promising for tandem devices due to their excellent optoelectronic properties and tunable bandgap 85–88 . It has been demonstrated that halide and metal substitution can effectively change the bandgap of perovskite materials 89–92 . Previously, some computational works indicate that a perovskite top cell with a bandgap in the range of 1.6–2 eV is suitable for forming tandem solar cells with Si bottom cell 32,93,94 .…”

“…[85][86][87][88] It has been demonstrated that halide and metal substitution can effectively change the bandgap of perovskite materials. [89][90][91][92] Previously, some computational works indicate that a perovskite top cell with a bandgap in the range of 1.6-2 eV is suitable for forming tandem solar cells with Si bottom cell. 32,93,94 Figure 8A shows the photograph of FA and FACs-based perovskite films with varied amount of Br component.…”