Regioselective Multisite Atomic-Chlorine Passivation Enables Efficient and Stable Perovskite Solar Cells

Abstract

Passivating defects using organic halide salts, especially chlorides, is an effective method to improve power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) arising from the stronger Pb−Cl bonding than Pb−I and Pb−Br bonding. However, Cl − anions with a small radius are prone to incorporation into the perovskite lattice that distorts the lead halide octahedron, degrading the photovoltaic performance. Here, we substitute atomic-Clcontaining organic molecules for widely used ionic-Cl salts, which not only retain the efficient passivation by Cl but also prevent the incorporation of Cl into the bulk lattice, benefiting from the strong covalent bonding between Cl atoms and organic frameworks. We find that only when the distance of Cl atoms in single molecules matches well with the distance of halide ions in perovskites can such a configuration maximize the defect passivation. We thereby optimize the molecular configuration to enable multiple Cl atoms in an optimal spatial position to maximize their binding with surface defects. The resulting PSCs achieve a certified PCE of 25.02%, among the highest PCEs for PSCs, and retain 90% of their initial PCE after 500 h of continuous operation.

Macrophage-Inspired Degradation-Activation System Enables Ultrasensitive Multicolor Detection of Haloacetic Acids via Janus Perovskite Halide Exchange

“…Besides, the fluorescence intensity initially increases and then decreases with increasing the 2Cl-HAA concentration (Figure b). At a low 2Cl-HAA concentration range (0–375 ppb), dissociated Cl – passivates the deep trap state on Br-JNP surface defects, thus resulting in an increase in fluorescence intensity . At the high 2Cl-HAA concentration range (750–6000 ppb), more Cl – ions are incorporated into the perovskite lattice, distorting the lead halide octahedron and inducing an adverse structure transformation to CsPbCl 3 with lower PLQY (the fluorescence intensity decreases) .…”

“…At a low 2Cl-HAA concentration range (0−375 ppb), dissociated Cl − passivates the deep trap state on Br-JNP surface defects, thus resulting in an increase in fluorescence intensity. 43 At the high 2Cl-HAA concentration range (750−6000 ppb), more Cl − ions are incorporated into the perovskite lattice, distorting the lead halide octahedron and inducing an adverse structure transformation to CsPbCl 3 with lower PLQY (the fluorescence intensity decreases). 44 As seen in Figures S20a and 5c, the wavelength shift shows a good logistic relationship (R 2 = 0.9999) with the concentration of 2Cl-HAA and a good linear relationship (R 2 = 0.9998) with lgC (C represents the concentration of 2Cl-HAA) in the range of 94−6000 ppb.…”

Synchronous Modulation of Energy Level Gradient and Defects for High‐Efficiency HTL‐Free Carbon‐Based All‐Inorganic Perovskite Solar Cells

“…[39] Hu et al confirmed that chlorine atoms can effectively passivate perovskite surface defects. [40] Theoretically, the passivator with both carbonyl and chlorine atoms, such as acyl chloride, may have stronger passivation ability.…”

Reduced electron relaxation time of perovskite films via g-C3N4 quantum dot doping for high-performance perovskite solar cells

“…29 In addition, less grain boundaries and thickness of perovskite layer are all also key elements contribute to high-efficiency PSCs. 30–34 Large grains can improve the perovskite film morphology and coverage effectively to reach an enhanced light-harvesting under unified light intensity. 35–39…”

“…29 In addition, less grain boundaries and thickness of perovskite layer are all also key elements contribute to high-efficiency PSCs. [30][31][32][33][34] Large grains can improve the perovskite lm morphology and coverage effectively to reach an enhanced light-harvesting under unied light intensity. [35][36][37][38][39] The studies of quantum dots modied PSCs mainly focused on the application of carbon quantum dots (CQDs) in devices, and the application of g-C 3 N 4 QDs in PSCs is rarely reported.…”