Stabilizing the cubic perovskite phase of CsPbI₃ nanocrystals by using an alkyl phosphinic acid

Abstract

CsPbI nanocrystals suffer from a facile cubic perovskite to orthorhombic phase transformation, which deteriorates their appealing optoelectronic properties. Here, we report a new colloidal synthesis that replaces the conventionally used oleic acid with an alkyl phosphinic acid to grow high-quality, phase-stable cubic perovskite CsPbI nanocrystals.

Halide Perovskite Nanocrystals for Next‐Generation Optoelectronics

“…Insets of (i and ii): Solutions of the respective washed NCs under UV light at different times following synthesis. Reproduced with permission . Copyright 2017, Royal Society of Chemistry.…”

“…Except amino and carboxylate groups, phosphonate functional unit, when introduced into the ligands, can also affect the PNC stability. Wang et al replaced the conventional OA with an alkyl phosphonic acid (TMPPA) to grow the CsPbI 3 NCs, demonstrating that the optical stability was significantly improved . In addition to the above‐mentioned functional groups, other inorganic capping ligands, such as PbSO 4 ‐oleate sulfobetaine, phosphocholine, and γ‐aminoacid sulfobetaine, could also affect the PNC stability and PLQY .…”

Lead Halide Perovskite Nanocrystals in the Research Spotlight: Stability and Defect Tolerance

“…Insets of (iii and iv): Solutions of the respective washed NCs under UV light at different times following synthesis. Adapted from ref (98). (d) Schematics showing the core–shell type of octylammonium lead bromide nanomaterials over MAPbBr 3 NPs.…”

“…By replacing the conventionally used OA with an alkyl phosphinic acid, Wang et al obtained phase-stable cubic perovskite CsPbI 3 NCs (Figure 6c(iii,iv)). 98 By changing the ligands, the as-prepared sample remained luminescent for over 20 days while the OA comparison sample showed no emission to the naked eye.…”

Metal halide perovskite nanocrystals and their applications in optoelectronic devices

“…When the perovskite NCs are exposed to polar solvents including moisture, they will precipitate, degrade, change phase, and ultimately degrade their optoelectronic performances. Jacek and coworkers used bis‐(2,2,4‐trimethylpentyl) phosphinic acid as a replacement of OA and greatly improved the stability of CsPbI 3 and restrained the phase transition of CsPbI 3 NCs from cubic α‐phase to nonfunctional orthorhombic δ‐phase . Liu et al changed the precursor solution of cesium, using trioctylphosphine (TOP) to prepare TOP‐PbI 2 precursor solution, and realized a nearly 100% PL QY.…”