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Wide-bandgap (WBG) perovskite solar cells (PSCs) are critical for high-efficiency tandem photovoltaic devices, but their practical application is severely limited by phase separation and poor film quality. To address these challenges, this study proposes a dual-additive passivation strategy using potassium thiocyanate (KSCN) and potassium chloride (KCl) to synergistically optimize the crystallinity and defect state of WBG perovskite films. The selection of KSCN/KCl is based on their complementary functionalities: K+ ions occupy lattice vacancies to suppress ion migration, Cl− ions promote oriented crystal growth, and SCN− ions passivate surface defects via Lewis acid-base interactions. A series of KSCN/KCl concentrations (relative to Pb) were tested, and the effects of dual additives on film properties and device performance were systematically characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), space-charge-limited current (SCLC), current-voltage (J-V), and external quantum efficiency (EQE) measurements. Results show that the dual additives significantly enhance film crystallinity (average grain size increased by 27.0% vs. control), reduce surface roughness (from 86.50 nm to 24.06 nm), and passivate defects-suppressing non-radiative recombination and increasing electrical conductivity. For WBG PSCs, the champion device with KSCN (0.5 mol%) + KCl (1 mol%) exhibits a power conversion efficiency (PCE) of 16.85%, representing a 19.4% improvement over the control (14.11%), along with enhanced open-circuit voltage (Voc: +2.8%), short-circuit current density (Jsc: +6.7%), and fill factor (FF: +8.9%). Maximum power point (MPP) tracking confirms superior operational stability under illumination. This dual-inorganic-additive strategy provides a generalizable approach for the rational design of stable, high-efficiency WBG perovskite films.
Details
Additives;
Scanning electron microscopy;
Defects;
Lattice vacancies;
Ion migration;
Ions;
Solar cells;
Crystallinity;
X-ray diffraction;
Crystal growth;
Electrical resistivity;
Grain size;
Potassium;
Quantum efficiency;
Surface defects;
Thiocyanates;
Photoelectrons;
Photovoltaic cells;
Radiative recombination;
Efficiency;
Perovskites;
Voltage;
Crystal lattices;
Photons;
Chloride;
Passivity;
Photovoltaics;
Costs;
Lewis acid;
Energy gap;
Energy conversion efficiency;
Crystal defects;
Surface roughness;
Phase separation;
Open circuit voltage;
Electrical conductivity;
Potassium chloride;
Short-circuit current;
Photoelectron spectroscopy;
Photoluminescence
1 College of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China, Zhejiang Institute of Medical Device Supervision and Testing, Hangzhou 310018, China
2 College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China
3 College of Optical Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China