Dimension control of in situ fabricated CsPbClBr2 nanocrystal films toward efficient blue light-emitting diodes

Abstract

In the field of perovskite light-emitting diodes (PeLEDs), the performance of blue emissive electroluminescence devices lags behind the other counterparts due to the lack of fabrication methodology. Herein, we demonstrate the in situ fabrication of CsPbClBr2 nanocrystal films by using mixed ligands of 2-phenylethanamine bromide (PEABr) and 3,3-diphenylpropylamine bromide (DPPABr). PEABr dominates the formation of quasi-two-dimensional perovskites with small-n domains, while DPPABr induces the formation of large-n domains. Strong blue emission at 470 nm with a photoluminescence quantum yield up to 60% was obtained by mixing the two ligands due to the formation of a narrower quantum-well width distribution. Based on such films, efficient blue PeLEDs with a maximum external quantum efficiency of 8.8% were achieved at 473 nm. Furthermore, we illustrate that the use of dual-ligand with respective tendency of forming small-n and large-n domains is a versatile strategy to achieve narrow quantum-well width distribution for photoluminescence enhancement.

Carrier dynamics in two-dimensional perovskites: Dion–Jacobson vs. Ruddlesden–Popper thin films

“…Due to the large formation energy of PEA-based 2D perovskites, PEA + cations are hardly consumed at the surface of the film, resulting in a higher concentration of 3D-like phases near the surface in perovskite films. 48 However, PEA + cations are preferentially consumed to form the n = 1 and n = 2 perovskite domains as such small- n value domains are kinetically easier to form at an early stage on the bottom of the films. 48–50…”

“…48 However, PEA + cations are preferentially consumed to form the n = 1 and n = 2 perovskite domains as such small- n value domains are kinetically easier to form at an early stage on the bottom of the films. 48–50…”

Efficient Sky‐Blue Light‐Emitting Diodes Based on Oriented Perovskite Nanoplates

“…The peaks at 15.2° and 21.4° are consistent with the diffraction from (100) and (110) crystal planes of 3D CsPbClBr 2 perovskite. [ 36 ] Notably, the (110) peak intensity of the EA‐TPPO‐treated perovskite is significantly lower, implying a possible orientation in the resultant film. The grazing incidence wide‐angle X‐ray scattering (GIWAXS) results in Figure 2d,e indicate that the diffraction rings of the two perovskites prepared with TPPO‐based AAE are significantly enhanced.…”

Photoluminescence investigations of sulfur quantum dots synthesized by a bubbling-assisted strategy

“…To-date the properties of S-dots are explained in the framework of the quantum connement in semiconductor nanocrystals. [4][5][6] For example, based on the size-dependent PL properties, blue and green emissions are reported for S-dots passivated with polyethylene glycol (PEG). Like semiconductor quantum dots (QDs), the emission color of S-dots blueshis with decreasing particle size.…”