Narrowing the Phase Distribution of Quasi‐2D Perovskites for Stable Deep‐Blue Electroluminescence

Nah, Yoonseo; Solanki, Devan; Dong, Yitong; Röhr, Jason A.; Taylor, André D.; Hu, Shu; Sargent, Edward H.; Kim, Dong Ha

doi:10.1002/advs.202201807

Cited by 30 publications

(33 citation statements)

References 35 publications

(34 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Notably the energy funneling process is critical in quasi‐2D perovskite films. [ 29 ] The PL of low‐dimensional phases during energy funneling leads to the asymmetry of the PL shape. [ 30 ] The transient absorption spectra demonstrated the existence of an energy transfer process (Figure S2, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Improving the Operational Stability of Near‐Infrared Quasi‐2D Perovskite Light‐Emitting Diodes by Cation Engineering

Wang

Ding

et al. 2022

Advanced Optical Materials

View full text Add to dashboard Cite

their operation stability is still far from the industrial standard, impeding their commercialization. [11] Ion migrations inside perovskites are a vital issue that undermines the operation stability of PeLEDs. [12,13] Various strategies have been employed to mitigate the negative effects of mobile ions, including the use of molecular additives, [14,15] metal doping, [16,17] and interfacial engineering. [18,19] Previous studies have revealed that PeLEDs with enhanced efficiency stability can be achieved by incorporating organic longchain cations into precursors to form quasi-2D Ruddlesden-Popper halide perovskites. [20][21][22] Theoretical calculations demonstrated that bulky organic cation layers between inorganic octahedral sheets in quasi-2D perovskites increase the defect formation energies of perovskites, acting as ion migration barriers to suppress ion migration and drastically enhance the operational stability of PeLEDs. [23][24][25] However, iodide ions in the FAPbI 3 lattice have lower activation energies and are more likely to migrate, [26,27] and the operational stability Although organic metal halide perovskite light-emitting diodes (PeLEDs) have been developed rapidly in recent years, their commercialization and further applications are still hindered by ion migration-induced inferior operational stability. Although the formation of a quasi-2D structure is a well-known solution that can efficiently suppress ion migration, the operation lifetime improvement is still limited. In this study, long-chain phenylbutanammonium is used to replace the commonly used phenethylammonium as the L-site cations. With large steric hindrance, ion migration inside the PeLEDs is effectively suppressed. Consequently, the PeLED with near-infrared emission at 763 nm exhibited an operational lifetime (T 90 ) of up to 5.3 h, which is 53-fold higher than that of the control device. This study demonstrates the feasibility of significant stability improvement using a simple cation engineering strategy for PeLEDs.

show abstract

Section: Resultsmentioning

confidence: 99%

Improving the Operational Stability of Near‐Infrared Quasi‐2D Perovskite Light‐Emitting Diodes by Cation Engineering

Wang

Ding

et al. 2022

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…[26][27][28] As a result, the blue PeLEDs with a broad n distribution are often subjected to low color purity and efficiency, therefore, narrow n distribution with minimized n = 1 and high-n phases in perovskites are mostly desired. [29] As the monodispersity of quantum wells is highly dependent on the spatial homogeneous distribution of organic cations in the precursor solution, [21,30] another different ammonium cations have been introduced to compete with PEA + to occupy the allocated positions in the perovskite lattice, which can disturb the PEA + aggregates and thus suppression of low n phases, such as PEAI/3-fluorophenylethylammonium iodide (m-F-PEA) and 1-naphthylmethylammonium iodide (NMAI), [10] PEABr and iso-propylammonium bromide (IPABr), [31][32] etc. In addition, introducing Lewis base additives into perovskites has become one of the most effective strategies to passivate defects and retard the growth of high-n domains via the coordination interaction.…”

Section: Introductionmentioning

confidence: 99%

Zwitterions Narrow Distribution of Perovskite Quantum Wells for Blue Light‐Emitting Diodes with Efficiency Exceeding 15%

Liu

Guo

et al. 2022

Advanced Materials

View full text Add to dashboard Cite

Since the first room temperature lead halide perovskite light-emitting diode (PeLED) reported in 2014, [5] green, red, and near-infrared PeLEDs have been developed rapidly, with external quantum efficiency (EQE) all over 20%. [6][7][8][9][10][11][12] However, the EQE of blue PeLEDs is still lagging behind, [13][14][15][16] which undoubtedly restricts their applications in full-color displays and white-light illuminations. [2,[17][18][19] Recently, quasi-2D perovskites have been considered as emerging candidates for efficient blue emission, with high exciton binding energy and efficient radiative recombination, thanks to the quantum confinement and dielectric confinement effects. [20][21][22][23] In quasi-2D perovskites, large organic ligands such as butylammonium (BA + ) and phenylethylammonium (PEA + ) can divide the perovskite lattice into a finite number of inorganic monolayers (n) and form quantum wells. While quasi-2D perovskites offer a feasible approach for high-efficiency blue PeLEDs, the elaborate control over the distribution of n domains presents a rising challenge. [24] Solution processed quasi-2D perovskites often contain a mixture of n phases with various bandgaps. [24,25] While quasi-two-dimensional (quasi-2D) perovskites have emerged as promising semiconductors for light-emitting diodes (LEDs), the broad-width distribution of quantum wells hinders their efficient energy transfer and electroluminescence performance in blue emission. In particular, the underlying mechanism is closely related to the crystallization kinetics and has yet to be understood. Here for the first time, the influence of bifunctional zwitterions with different coordination affinity on the crystallization kinetics of quasi-2D perovskites is systematically investigated. The zwitterions can coordinate with Pb 2+ and also act as co-spacer organic species in quasi-2D perovskites, which collectively inhibit the aggregation of colloidal precursors and shorten the distance of quantum wells. Consequently, restricted nucleation of high-n phases and promoted growth of low-n phases are achieved with moderately coordinated zwitterions, leading to the final film with a more concentrated n distribution and improved energy transfer efficiency. It thus enables high-efficiency blue LEDs with a recorded external quantum efficiency of 15.6% at 490 nm, and the operation stability has also been prolonged to 55.3 min. These results provide useful directions for tuning the crystallization kinetics of quasi-2D perovskites, which is expected to lead to high-performance perovskite LEDs.

show abstract

“…Figure 5b shows the EL spectra under forward bias of 3.4, 3.8, and 4.2 V. The EL peak is located at 442 nm with an fwhm of 13 nm, which is one of the narrowest fwhm report to date among deep-blue perovskite EL devices. 43 This confirms that large-n domains are eliminated, and the phase purity of n = 2 perovskites is significantly increased. The corresponding Commission Internationale de l'Eclairage (CIE) color coordinate is (0.16, 0.02).…”

Section: ■ Results and Discussionmentioning

confidence: 55%

“…On the basis of the pure-phase 2D film, we fabricated EL devices using the following structure (Figure a): ITO/PEDOT:PSS/PVK/perovskite/TPBi/LiF/Al. Figure b shows the EL spectra under forward bias of 3.4, 3.8, and 4.2 V. The EL peak is located at 442 nm with an fwhm of 13 nm, which is one of the narrowest fwhm report to date among deep-blue perovskite EL devices . This confirms that large- n domains are eliminated, and the phase purity of n = 2 perovskites is significantly increased.…”

Section: Resultsmentioning

confidence: 62%

Illustrating the Key Role of Hydrogen Bonds in Fabricating Pure-Phase Two-Dimensional Perovskites

et al. 2022

View full text Add to dashboard Cite

Two-dimensional (2D) layered perovskites consisting of multiple quantum wells are emerging as functional materials to achieve high-performance and stable optoelectronic devices. Pure-phase 2D perovskites provide a platform to investigate their fundamental properties; however, the deposition of pure-phase films remains a scientific challenge. Herein, we reveal the critical role of hydrogen bonds in fabricating pure-phase 2D perovskites. We demonstrate that the phenylalkylammonium molecules exhibit different hydrogen bonding abilities with formamidinium (FA) by varying their alkyl chain lengths. The stronger hydrogen bonding-assisted FA localization at the corner of [PbBr6]4– octahedral layer plays a key role in the crystallization of n = 2 pure-phase perovskites. On the basis of these understandings, we demonstrate deep-blue electroluminescence with an emission peak at 442 nm and a narrow line width of 13 nm, showing a peak external quantum efficiency of 0.19%. This finding opens up a new avenue for domain distribution control of 2D perovskites.

show abstract

Narrowing the Phase Distribution of Quasi‐2D Perovskites for Stable Deep‐Blue Electroluminescence

Cited by 30 publications

References 35 publications

Improving the Operational Stability of Near‐Infrared Quasi‐2D Perovskite Light‐Emitting Diodes by Cation Engineering

Improving the Operational Stability of Near‐Infrared Quasi‐2D Perovskite Light‐Emitting Diodes by Cation Engineering

Zwitterions Narrow Distribution of Perovskite Quantum Wells for Blue Light‐Emitting Diodes with Efficiency Exceeding 15%

Illustrating the Key Role of Hydrogen Bonds in Fabricating Pure-Phase Two-Dimensional Perovskites

Contact Info

Product

Resources

About