Synthesis of Red Cesium Lead Bromoiodide Nanocrystals Chelating Phenylated Phosphine Ligands with Enhanced Stability

Abstract

Two new phosphine ligands, diphenylmethylphosphine (DPMP) and triphenylphosphine (TPP), were introduced onto cesium lead bromoiodide nanocrystals (CsPbBrI 2 NCs) to improve air stability in the ambient atmosphere. Incorporating DPMP or TPP ligands can also enhance film-forming and optoelectronic properties of the CsPbBrI 2 NCs. The results reveal that DPMP is a better ligand to stabilize the emission of CsPbBrI 2 NCs than TPP after storage for 21 days. The increased carrier lifetime and photoluminescence quantum yield (PLQY) of perovskite NCs are due to the surface passivation by DPMP or TPP ligands, which reduces nonradiative recombination at the trap sites. The DPMP and TPP-treated CsPbBrI 2 NCs were successfully utilized as red emitters for fabricating perovskite light-emitting diodes with enhanced performance and prolonged device lifetime relative to the pristine one.

High-Quality CsPbX3 (X = Cl, Br, or I) Perovskite Nanocrystals Using Ascorbic Acid Post-Treatment: Implications for Light-Emitting Applications

“…They are thermodynamically unfavorable and undergo a nonperovskite phase (δ-phase) transition at room temperature. On the one hand, many efforts have been reported to stabilize iodide perovskite NCs by critically passivating PNCs and using them for optoelectronics and photovoltaics. − On the other hand, mixed halide perovskites like CsPbBrI 2 , which are relatively more stable than CsPbI 3 PNCs, are a better choice for device applications . But the photoinduced halide segregation is unavoidable, limiting the use of them in practical applications.…”

“…36−38 On the other hand, mixed halide perovskites like CsPbBrI 2 , which are relatively more stable than CsPbI 3 PNCs, are a better choice for device applications. 39 But the photoinduced halide segregation is unavoidable, limiting the use of them in practical applications.…”

Defects in lead halide perovskite light-emitting diodes under electric field: from behavior to passivation strategies

“…One carboxylate facilitated the conversion of TOP to TOPO, whereas the other interacted with a Br − dangling bond, resulting in a Pbrich surface with carboxylate-based passivation. In addition to TOP, phosphine-containing compounds such as triphenylphosphine (TPP), 140,141 diphenylphosphine (DPP), 142 and tributylphosphine, have also been widely explored, each showing varying degrees of enhancement in the performance of NCs.…”

Frontiers in Green Perovskite Light‐Emitting Diodes

“…At present, researchers have found some substances that can be used to replace the traditional ligands, including didodecyldimethylammonium bromide (DDAB), trans-cinnamic acid (TCA), phenylethylammonium (PEA), diphenylmethylphosphine (DPMP) and so on. [148][149][150][151][152][153] Additionally, for quasi-2D perovskites, ligands can form quantum wells and passivate perovskite surface defects while providing higher stability and better optical properties. Nowadays, researchers have used octylamine (OTAm), 1-naphthylmethylammonium (NMA), ethoxylated trimethylolpropane triacrylate (ETPTA), etc.…”