Stable and Bright Electroluminescent Devices utilizing Emissive 0D Perovskite Nanocrystals Incorporated in a 3D CsPbBr₃ Matrix

Abstract

The 0D cesium lead halide perovskite Cs4PbBr6 has drawn remarkable interest due to its highly efficient robust green emission compared to its 3D CsPbBr3 counterpart. However, seizing the advantages of the superior photoluminescence properties for practical light‐emitting devices remains elusive. To date, Cs4PbBr6 has been employed only as a higher‐bandgap nonluminescent matrix to passivate or provide quantum/dielectric confinement to CsPbBr3 in light‐emitting devices and to enhance its photo‐/thermal/environmental stability. To resolve this disparity, a novel solvent engineering method to incorporate highly luminescent 0D Cs4PbBr6 nanocrystals (perovskite nanocrystals (PNCs)) into a 3D CsPbBr3 film, forming the active emissive layer in single‐layer perovskite light‐emitting electrochemical cells (PeLECs) is designed. A dramatic increase of the maximum external quantum efficiency and luminance from 2.7% and 6050 cd m−2 for a 3D‐only PeLEC to 8.3% and 11 200 cd m−2 for a 3D–0D PNC device with only 7% by weight of 0D PNCs is observed. The majority of this increase is driven by the efficient inherent emission of the 0D PNCs, while the concomitant morphology improvement also contributes to reduced leakage current, reduced hysteresis, and enhanced operational lifetime (half‐life of 129 h), making this one of the best‐performing LECs reported to date.

The Synergy of the Buried Interface Surface Energy and Temperature for Thermal Evaporated Perovskite Light-Emitting Diodes

“…What’s more, Cs 4 PbBr 6 coexists with CsPbBr 3 in films on PVK and Poly-TPD, but it is not obvious in films on PEDOT:PSS and NiO x . Some literature states that Cs-rich Cs 4 PbBr 6 with a broad bandgap can provide type-I confinement to 3D CsPbBr 3 and even passivate the surface of CsPbBr 3 without any resulting strain . So that the buried interface affects the properties of the thermally evaporated perovskite film by altering the crystallographic characteristics.…”

A Polymer Strategy toward High‐Performance Multifunctional Perovskite Optoelectronics: From Polymer Matrix to Device Applications

“…Controlled dimensional perovskites by polymers can generate novel optical properties. [209][210][211][212] In addition, perovskite substances in a polymer matrix can also produce other novel optical properties. [169,[213][214][215][216][217] Liu et al presented that the bilayer structured devices were constructed by embedding perovskite nanocrystals in a polymer (polyacrylonitrile, PAN) matrix and coupling with soft helix based on the chiral liquid crystal (Figure 17a).…”

“…Controlled dimensional perovskites by polymers can generate novel optical properties. [ 209–212 ] In addition, perovskite substances in a polymer matrix can also produce other novel optical properties. [ 169,213–217 ] Liu et al.…”

Revealing the Low-Temperature Interplay of Electronic, Ionic, and Optical Effects in Perovskite Electroluminescent Devices

“…Under applied bias, the electrolyte facilitates the redistribution of the additive ions while preserving the perovskite structure. Differential ion motion in these PeLECs is strongly supported by the long-lasting devices produced , and the color stability exhibited by devices with mixed halide perovskites. , Thus, these devices exhibit rich device physics while offering high performance among perovskite light-emitting devices.…”

“…One challenge to implementing perovskites as light-emitting devices has been ion migration within the material, leading to hysteresis, color drift, and device failure. Our strategy for achieving stable perovskite light-emitting devices is to fabricate them as perovskite light-emitting electrochemical cells (PeLECs). − PeLECs leverage ion motion to form electrical double layers (EDLs) at the electrodes , and possible doping effects, leading to efficient and balanced charge injection, resulting in high-efficiency performance from a single-layer device. To avoid the detrimental effects associated with ionic dissociation of the perovskite lattice, these devices leverage differentiated ion motion through the motion of additive ions in place of the perovskite ions. ,, A polymer electrolyte [such as poly­(ethylene oxide) (PEO)] and a salt with small, highly mobile ions (such as LiPF 6 ) are cast as a blended film with the perovskite.…”