Effective lewis base additive with S-donor for efficient and stable CsPbI2Br based perovskite solar cells

Potassium Salt Coordination Induced Ion Migration Inhibition and Defect Passivation for High-Efficiency Perovskite Solar Cells

“…22−24 According to the Lewis acid−base coordination theory, a Lewis base additive is considered as the cationic defect passivator due to its lone pair electrons, which could interact with cations by forming the coordination bond. 25,26 Typical Lewis base additives such as thiophene, pyridine, carboxyl derivatives, and amino acids have been reported to suppress the carrier nonradiative recombination and increase the carrier lifetime via defect passivation. 27,28 Meanwhile, the potential mechanism of controlling the annealing crystallization by forming a Lewis acid−base adduct is studied, with enhanced crystallinity, larger grain size, and fewer grain boundaries.…”

“…To date, a lot of effort has been made to decline trap states, reduce grain boundaries, and inhibit ion migration, including solvent engineering, interface engineering, and additive engineering. − Among them, additive engineering is an effective strategy to passivate the trap states and improve perovskite film quality for the preparation of efficient and stable PSCs due to its low cost and simple process. − According to the Lewis acid–base coordination theory, a Lewis base additive is considered as the cationic defect passivator due to its lone pair electrons, which could interact with cations by forming the coordination bond. , Typical Lewis base additives such as thiophene, pyridine, carboxyl derivatives, and amino acids have been reported to suppress the carrier nonradiative recombination and increase the carrier lifetime via defect passivation. , Meanwhile, the potential mechanism of controlling the annealing crystallization by forming a Lewis acid–base adduct is studied, with enhanced crystallinity, larger grain size, and fewer grain boundaries. , For anion defects (uncoordinated I – , Pb–I antisite), the passivation strategy of Lewis acid is mainly focused on fullerene derivatives, in which the ability of the electron acceptor is attributed to strain of its spherical structure. − Besides the Lewis base and acid additive, the metal cations are also widely studied as the defect passivator in perovskites, including the alkali cations and transition metal cations such as Na + , K + , Cs + , Ni 2+ , and Eu 3+ . − Due to the charge of outermost valence electrons lost or gained, metal cations could interact with charged defects through electrostatic force. In addition, it is worth noting that K + could be energetically favorable to occupy the interstitial sites within the perovskite lattice with the appropriate radius of 1.38 Å, which hinders the formation of an iodide Frenkel defect caused by I – migration, eliminating the hysteresis of PSCs significantly .…”

2D Non‐Layered In2S3 as Multifunctional Additive for Inverted Organic‐Free Perovskite Solar Cells with Enhanced Performance

“…Meanwhile, the Pb 4 f signals (4 f 7/2 /4 f 5/2 ) are downshifted from 143.13/138.25 to 142.93/138.05 eV upon the Nano‐In 2 S 3 doping, indicative of the passivation effect of Nano‐In 2 S 3 via the formation of Pb—S coordination bond. [ 46 ] Thus, the unsaturated In—S dangling bonds on the surface of Nano‐In 2 S 3 not only display a coordination effect for perovskite precursors but also play an important role in passivating unsaturated Pb 2+ defects in the perovskite film. To further estimate the quality of perovskite films without and with Nano‐In 2 S 3 , their steady‐state photoluminescence (PL) spectra are presented in Figure 2c.…”

Multidimensional Function Upgradation of All‐Inorganic CsPbIBr2 Perovskite Film by Doping an Ionic Additive for Carbon–Electrode‐Based Solar Cells

“…For Pb 4f XPS spectra, as shown in Figure 2e, two peaks located at 143.4 and 138.5 eV for Pb 4f 5/2 and 4f 7/2 are detected. [ 31 ] Compared to the control film, the incorporation of TBAPF 6 results in the peak shift to lower binding energy, an indicator of lowered oxidation state of Pb 2+ ; that is to say, there is an electron donation effect between TBA + cation in TBAPF 6 and under‐coordinated Pb 2+ ions. [ 32 ] Therefore, taking the improved film quality into consideration, the defects are expected to be significantly reduced.…”