Ligand‐Mediated Revival of Degraded α‐CsPbI₃ to Stable Highly Luminescent Perovskite

Abstract

Although α‐CsPbI3 is regarded as an attractive optical luminophore, it is readily degraded to the optically inactive δ‐phase under ambient conditions. Here, we present a simple approach to revive degraded (“optically sick”) α‐CsPbI3 through “medication” with thiol‐containing ligands. The effect of different types of thiols is systematically studied through optical spectroscopy. The structural reconstruction of degraded α‐CsPbI3 nanocrystals to cubic crystals in the presence of thiol‐containing ligands is visualized through high‐resolution transmission electron microscopy and supported by X‐ray diffraction analysis. We found that 1‐dodecanethiol (DSH) effectively revives degraded CsPbI3 and results in high immunity towards moisture and oxygen, hitherto unreported. DSH facilitates the passivation of surface defects and etching of degraded Cs4PbI6 phase, thus reverting them back to the cubic CsPbI3 phase, leading to enhanced PL and environmental stability.

Ultrastable Photodetectors Based on Blue CsPbBr3 Perovskite Nanoplatelets via a Surface Engineering Strategy

“…12,28 Obviously, as shown in Figure 4c, the differential charge density diagram of Br, Pb, and O planes with ligands indicates the presence of shared electrons between Br and O atoms, while there is obvious electron transfer between O and Pb atoms. 28 The redistribution of electrons among Pb, Br, and O atoms leads to a strong interaction between them, thus improving the binding energy between ligands and NPLs. 12,28 Photodetectors based on two types of NPLs have been constructed, and the schematic structure and optical images of the photodetector are shown in Figure 5a.…”

“…28 The redistribution of electrons among Pb, Br, and O atoms leads to a strong interaction between them, thus improving the binding energy between ligands and NPLs. 12,28 Photodetectors based on two types of NPLs have been constructed, and the schematic structure and optical images of the photodetector are shown in Figure 5a. The two types of NPL materials were spin-coated onto glass substrates, followed by the deposition of a crossbar silver (Ag) electrode with a spacing of 50 μm.…”

“…It is evident that the system with the ATDA ligand exhibits higher stability, which is attributed to the longer chain ligand OA that induces more charge transfer, thereby reducing the binding stability between the ligand and NPLs. , Obviously, as shown in Figure c, the differential charge density diagram of Br, Pb, and O planes with ligands indicates the presence of shared electrons between Br and O atoms, while there is obvious electron transfer between O and Pb atoms . The redistribution of electrons among Pb, Br, and O atoms leads to a strong interaction between them, thus improving the binding energy between ligands and NPLs. , …”

“…DFT was calculated to investigate the role of introducing ATDA ligands. , The density of states (DOS) results from the DFT calculations reveal that the introduction of ligands causes a redistribution of electron density between the Br, Pb, and O atoms. Specifically, Pb gains electrons, causing the overall electron states to shift toward higher energy regions, as shown in Figure a, which only displays the electron DOS near the Fermi level.…”

Methanol as an anti-solvent to improve the low open-circuit voltage of CsPbBr3 perovskite solar cells prepared with water

“…However, CsPbI 3 crystals are prone to degradation into the inactive δ phase at room temperature. 14,15 Although the partial substitution of I ions with Br ions can alleviate this phase transition, the stability of these mixed Br-doped inorganic perovskites under ambient conditions remains unsatisfactory. [16][17][18][19] Among various inorganic PSCs, CsPbBr 3 shows the best humidity and thermal stability, which is not only suitable for solar cells but also for various other optoelectronic devices.…”