Understanding the Improvement in the Stability of a Self-Assembled Multiple-Quantum Well Perovskite Light-Emitting Diode

Li, Cheng; Wang, Nana; Guerrero, Antonio; Zhong, Yu; Long, Huan; Miao, Yanfeng; Bisquert, Juan; Wang, Jianpu; Huettner, Sven

doi:10.1021/acs.jpclett.9b02467

Cited by 42 publications

(52 citation statements)

References 54 publications

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“…[ 62 ] Reducing defect/ion accumulation at perovskite/external contacts can increase the device stability as it has been demonstrated with the help of 2D or low‐dimensional layered perovskites. [ 63 ] PCBM, however, may have to be used with care in LED devices as PCBM can greatly quench the emission of LEDs. Immobile (i.e., polymerized) derivatives, instead may become of great interest as PSC/ETL interlayers.…”

Section: Resultsmentioning

confidence: 99%

Role of PCBM in the Suppression of Hysteresis in Perovskite Solar Cells

Zhong

Hufnagel

Thelakkat

et al. 2020

Adv Funct Materials

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117

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The power conversion efficiency of inorganic–organic hybrid lead halide perovskite solar cells (PSCs) is approaching that of those made from single crystalline silicon; however, they still experience problems such as hysteresis and photo/electrical‐field‐induced degradation. Evidences consistently show that ionic migration is critical for these detrimental behaviors, but direct in‐situ studies are still lacking to elucidate the respective kinetics. Three different PSCs incorporating phenyl‐C61‐butyric acid methyl ester (PCBM) and a polymerized form (PPCBM) is fabricated to clarify the function of fullerenes towards ionic migration in perovskites: 1) single perovskite layer, 2) perovskite/PCBM bilayer, 3) perovskite/PPCBM bilayer, where the fullerene molecules are covalently linked to a polymer backbone impeding fullerene inter‐diffusion. By employing wide‐field photoluminescence imaging microscopy, the migration of iodine ions/vacancies under an external electrical field is studied. The polymerized PPCBM layer barely suppresses ionic migration, whereas PCBM readily does. Temperature‐dependent chronoamperometric measurements demonstrate the reduction of activation energy with the aid of PCBM and X‐ray photoemission spectroscopy (XPS) measurements show that PCBM molecules are viable to diffuse into the perovskite layer and passivate iodine related defects. This passivation significantly reduces iodine ions/vacancies, leading to a reduction of built‐in field modulation and interfacial barriers.

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Section: Resultsmentioning

confidence: 99%

Role of PCBM in the Suppression of Hysteresis in Perovskite Solar Cells

Zhong

Hufnagel

Thelakkat

et al. 2020

Adv Funct Materials

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117

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“…However, in the low dimensional NCs, there is almost no grain boundary, and the process of ion migration is different from that of 3D perovskite. According to our recent research [ 71 ], activated ion migration can promote the degradation of quantum dots, in which stable ion supply is needed to modify the perovskite / external contact interface. Therefore, the organic layer is inserted into MQW perovskite LED as the barrier of ion movement, which successfully inhibits ion migration and improves the stability.…”

Section: Measures To Improve the Stability Of Mhp-ncsmentioning

confidence: 99%

The Stability of Metal Halide Perovskite Nanocrystals—A Key Issue for the Application on Quantum-Dot-Based Micro Light-Emitting Diodes Display

et al. 2020

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The metal halide perovskite nanocrystal (MHP-NC), an easy-to-fabricate and low cost fluorescent material, is recognized to be among the promising candidates of the color conversion material in the micro light-emitting diode (micro-LED) display, providing that the stability can be further enhanced. It is found that the water steam, oxygen, thermal radiation and light irradiation—four typical external factors in the ambient environment related to micro-LED display—can gradually alter and destroy the crystal lattice. Despite the similar phenomena of photoluminescence quenching, the respective encroaching processes related to these four factors are found to be different from one another. The encroaching mechanisms are collected and introduced in separate categories with respect to each external factor. Thereafter, a combined effect of these four factors in an environment mimicking real working conditions of micro-LED display are also introduced. Finally, recent progress on the full-color application of MHP-NC is also reviewed in brief.

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“…The spectroscopic technique monitors the variation of the light absorption of a material under electric field‐modulation, which has been applied to study various materials and bio‐systems. [ 19–23 ] In particular, EA spectroscopy has been demonstrated as a powerful tool to characterize the band gap, exciton binding energy, change of dipole moment, charge polarization of perovskite materials, and the built‐in field in perovskite‐based devices. [ 24–26 ] Considering that different materials have specific absorption characteristic peaks, it is possible to use EA spectroscopy to distinguish the property change of each functional layer in a device.…”

Section: Introductionmentioning

confidence: 99%

Degradation Mechanism of Perovskite Light‐Emitting Diodes: An In Situ Investigation via Electroabsorption Spectroscopy and Device Modelling

Guo

Jia

et al. 2020

Adv Funct Materials

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The past few years have seen a significant improvement in the efficiency of organometal halide-perovskite-based light-emitting diodes (PeLEDs). However, poor operation stability of the devices still hinders the commercialization of this technology for practical applications. Despite extensive studies on the degradation mechanisms of perovskite thin films, it remains unclear where and how degradation occurs in a PeLED. Electroabsorption (EA) spectroscopy is applied to study the degradation process of PeLEDs during operation and directly evaluates the stability of each functional layer (i.e., charge transporting layers and light-emitting layer) by monitoring their unique optical signatures. The EA measurements unambiguously reveal that the degradation of the PeLEDs occurs predominantly in the perovskite layer. With finite-element method-based device modeling, it is further revealed that the degradation may initiate from the interface between the perovskite and hole transporting layers and that vacancy, antisite, or interstitial defects can further accelerate this degradation. Inspired by these observations, a surface-treatment step is introduced to passivate the perovskite surface with phenethylammonium iodide. The passivation leads to a drastic enhancement of the PeLED stability, with the operation lifetime increased from 1.5 to 11.3 h under a current density of 100 mA cm −2 .light emission properties of PeLEDs, and the external quantum efficiency (EQE) and radiance of the best -performing nearinfrared PeLED has already reached 21.6% and 308 W (sr × m 2 ) −1 , respectively. [4] However, most reported PeLEDs degrade rapidly during operation, losing luminescence within several hours. [5][6][7] Stability has been a general issue for almost all perovskite-based optoelectronic devices, but it is particularly problematic in PeLEDs where the current density is high and the energy conversion efficiency is still low. Some research efforts have been made to study the degradation mechanisms of perovskite solar cells and LEDs through characterization of perovskite films, which include in situ X-ray diffraction (XRD) monitoring of phase evolution, [8][9][10][11][12][13] time-of-flight secondary ion mass spectrometry investigation of water penetration in perovskite films, [14] and time-resolved photoluminescence measurements. [12] Prakasam et al. peeled off the top electrode layer of a PeLED after bias stressing and studied the underlying perovskite layer using scanning electron microscopy, structural characterization techniques, and energy-dispersive X-ray profiling. [15] The results suggest decomposition of the perovskite layer during operation, leading to local delamination of the top electrode layer. Studies have also been done to directly improve the stability of the perovskite layer through selection of stable cations, [16] composition tuning and inclusion of additives in the precursor, [17] as well as introduction of a doped electron transport layer, [18] and development of a core-shell perovskite grain structure. [7] De...

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Understanding the Improvement in the Stability of a Self-Assembled Multiple-Quantum Well Perovskite Light-Emitting Diode

Cited by 42 publications

References 54 publications

Role of PCBM in the Suppression of Hysteresis in Perovskite Solar Cells

Role of PCBM in the Suppression of Hysteresis in Perovskite Solar Cells

The Stability of Metal Halide Perovskite Nanocrystals—A Key Issue for the Application on Quantum-Dot-Based Micro Light-Emitting Diodes Display

Degradation Mechanism of Perovskite Light‐Emitting Diodes: An In Situ Investigation via Electroabsorption Spectroscopy and Device Modelling

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