Efficient Ligand Passivation Enables Ultrastable CsPbX₃ Perovskite Nanocrystals in Fully Alcohol Environments

Abstract

Halide perovskite nanocrystals (PNCs) have demonstrated their wide potential to fabricate efficient optoelectronic devices and to prepare promising photocatalysts for solar‐driven photo(electro)chemical reactions. However, their use in most of the practical applications is limited due to the instability of PNCs in polar environments. Here, the preparation of non‐encapsulated CsPbX3 nanocrystals dispersed in fully alcohol environments, with outstanding stability through surface defect passivation strategy is reported. By using didodecyldimethylammonium bromide (DDAB) during material post‐treatment, highly luminescent CsPbBr3 PNCs with remarkable stability in methanol/butanol medium up to 7 months with near‐unity photoluminescence quantum yield are achieved. This approach is extrapolated to stabilize iodine‐based CsPbBr3‐xIx and CsPbI3 PNCs, showing an improvement of their photoluminescence features and stability in these high polar alcohols up to 6 h. DDAB mediates the defect suppression through ligand exchange and avoids the full permeation of alcohol to be in contact with the PNCs. In this context, DDAB induces ionization of alcohol molecules to strengthen the surface passivation. The findings open the door to the development of long‐term stable CsPbX3 PNCs with high optical performance to be used in polar environments.

Surface engineering in CsPbX3 quantum dots: from materials to solar cells

“…We can design it in the following two ways: A in situ ligand exchange. Ligands such as DDBA, 78,79,[82][83][84][85][86] IDA, 66 and TOP 96 proved to be effective in enhancing the optical properties of CsPbX 3 QDs. B Passivation of QDs in the purification process.…”

“…Subsequently, DDAB and its derivatives have been widely used in CsPbBr 3 QDs. [82][83][84][85][86] Park et al 84 studied the effect of the bulkiness of quaternary ammonium bromide (QAB) ligands on the properties and stability of CsPbBr 3 QDs. The less bulky QAB ligands surrounded the surface of QDs effectively, and brought better surface passivation and less aggregation compared to bulky QAB ligands, and finally the optical property and stability of CsPbBr 3 QDs were enhanced.…”

Impact of core–shell perovskite nanocrystals for LED applications: successes, challenges, and prospects

“…1,86 In this context, the shelling mechanism can be investigated by detecting optical illusions occurring during the shelling process of the core-perovskite nanocrystals. A quantitative PL setup to measure PLQY and determine carrier lifetime would quantify radiative recombination over total recombination 42 to study the effects of shelling. In particular, organic shelling leads to minimizing the surface defects, as can be explained from this study.…”

Aging CsPbBr3 Nanocrystal Wafer for Ultralow Ionic Migration and Environmental Stability for Direct X-ray Detection

“…X-ray detection has widespread applications, including medical computed tomography imaging, industrial product quality inspection, airport security checks, scientific research, and space exploration. − In recent years, halide perovskite semiconductors have emerged as a promising next-generation commercial X-ray detection option, given their excellent properties, such as large mobility-lifetime product (μτ), high X-ray attenuation coefficient, and defect-tolerant nature. − In addition, perovskites with a thickness of hundred micrometers were realized for the absorption of X-rays through single-crystal growth, ,, hot-pressing, − and printing methods. − For example, Pan and colleagues reported sensitivities (55,684 μC Gy air –1 cm –2 ) of CsPbBr 3 X-ray detectors far exceeding those of commercialized CZT detectors through hot-pressing methods . Although the potential breakthrough of halide perovskites could reduce the required X-ray doses for imaging and minimize X-ray-related damage, tough problems must be addressed, such as serious ionic migration ,− and long-term stability. − …”