Highly stable all-inorganic CsPbBr₃ nanocrystals film encapsulated with alumina by plasma-enhanced atomic layer deposition

Device Engineering for All-Inorganic Perovskite Light-Emitting Diodes

“…Ding et al reported an approach to prepare stable and water-soluble CsPbX 3 /SiO 2 nanocomposites by encapsulating the CsPbX 3 QDs into silica nanoplates, where the application of CsPbX 3 /SiO 2 in white LEDs and cell imaging showed ultrastability and high biocompatibility [263]. Zhu et al provided a scheme to improve the stability of CsPbBr 3 nanocrystals film by depositing Al 2 O 3 on nanocrystals film surface for via plasma enhanced atomic layer deposition [264], where the dense Al 2 O 3 film also exhibited an encapsulation effect [265]. Shi et al presented an approach to combine localized surface plasmons and core/shell nanostructure configuration in a single PeLED, where the PeLEDs without encapsulation presented a substantially improved operation stability against water and oxygen degradation (30-day storage in air ambient, 85% humidity) [266].…”

Nanoscale Encapsulation of Perovskite Nanocrystal Luminescent Films via Plasma-Enhanced SiO2 Atomic Layer Deposition

“…Atomic layer deposition (ALD) has been widely employed to prepare uniform films at the atomic level and is based on the self-limiting half reactions, which is beneficial to precisely controlling the composition and thickness of films. − Over the past few years, Al 2 O 3 ALD has been applied to stabilize perovskite NCs including CsPbX 3 NCs. ,− In the previous work, our group developed a mild low-temperature Al 2 O 3 ALD process to enhance the stability of CsPbBr 3 quantum dot–silica sphere in light, water, and heat, which originated from the crystal structure stabilization after ALD coating . Although the Al 2 O 3 coating improves CsPbX 3 NCs’ stability, a significant photoluminescence (PL) quenching of NCs is typically observed upon Al 2 O 3 ALD, hindering the performance and applicability. − The interaction between the metalorganic precursor trimethylaluminum (TMA) for Al 2 O 3 ALD and capping oleic acid (OA) ligands on the NCs’ surface leads to reorganization of the ligand binding from Pb to Al, which creates deleterious undercoordinated Pb atoms that causes PL quenching. , In addition, the hydrolysis reaction of the Al 2 O 3 layer with external moisture is another problem, which limits their further application . Accordingly, it is necessary to seek a new ALD process with the ability to encapsulate the perovskite NCs without damaging the optical performance of the NCs.…”