Recombination Dynamics Study on Nanostructured Perovskite Light‐Emitting Devices

Chen, Ziming; Li, Zhenchao; Zhang, Chongyang; Jiang, Xiaofang; Chen, Dongcheng; Xue, Qifan; Liu, Meiyue; Su, Shi‐Jian; Yip, Hin‐Lap; Cao, Yong

doi:10.1002/adma.201801370

Cited by 108 publications

(117 citation statements)

References 52 publications

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“…To understand the role of Auger recombination and spatial carrier distribution qualitatively, recombination rate R ( n ) can be divided into three components: trap‐assisted non‐radiative recombination ( An ), radiative recombination ( Bn 2 ), and Auger recombination ( Cn 3 ) (Equation (2), where A , B , and C are coefficients): [ 25,28,40,41 ]

R (n) = A n + B n^{2} + C n^{3}

…”

Section: Resultsmentioning

confidence: 99%

Low Roll‐Off Perovskite Quantum Dot Light‐Emitting Diodes Achieved by Augmenting Hole Mobility

Wang

Teng

et al. 2020

Adv Funct Materials

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The external quantum efficiencies (EQEs) of perovskite quantum dot lightemitting diodes (QD-LEDs) are close to the out-coupling efficiency limitation. However, these high-performance QD-LEDs still suffer from a serious issue of efficiency roll-off at high current density. More injected carriers produce photons less efficiently, strongly suggesting the variation of ratio between radiative and non-radiative recombination. An approach is proposed to balance the carrier distribution and achieve high EQE at high current density. The average interdot distance between QDs is reduced and this facilitates carrier transport in QD films and thus electrons and holes have a balanced distribution in QD layers. Such encouraging results augment the proportion of radiative recombination, make devices with peak EQE of 12.7%, and present a great device performance at high current density with an EQE roll-off of 11% at 500 mA cm −2 (the lowest roll-off known so far) where the EQE is still over 11%.their PL QYs. Diverse approaches have been proposed to boost the performance of QD-LEDs via surface passivation, [19] modification of carrier transport layer, [20][21][22] and anion exchange. [12] QD-LEDs have therefore demonstrated an impressive quick increase of peak external quantum efficiencies (EQEs) from 0.01% to 21.3% within 4 years, suggesting perovskite QDs as promising new-generation optoelectronic semiconductor materials. [6,7,12,21] In spite of the rapid development of perovskite QD-LEDs, at present, the EQEs of these devices tend to be acquired at low current density and manifest significant loss at higher current density, which is known as efficiency roll-off. In best-performed perovskite QD-LEDs, [12] the maximum EQE was obtained at a current density lower than 1 mA cm −2 ; when the current density reached 100 mA cm −2 , the EQE became only about 1%, indicating the efficiency loss reached 95%. Such efficiency loss actually limits achievable brightness and leads to excessive power consumption.Apart from perovskite QD-LEDs, perovskite film-LEDs present similar issues and recently, a few studies have come up with several methods to minimize EQE droop. Zou et al. and Yang et al. concluded that it was luminescence quenching caused by Auger recombination that was responsible for the efficiency roll-off. [23,24] To reduce carrier density in quantum wells (QWs), increased QW width was acquired via different

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R (n) = A n + B n^{2} + C n^{3}

…”

Section: Resultsmentioning

confidence: 99%

Low Roll‐Off Perovskite Quantum Dot Light‐Emitting Diodes Achieved by Augmenting Hole Mobility

Wang

Teng

et al. 2020

Adv Funct Materials

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“…To enhance device performance, intense efforts were made in recent years for developing new perovskite materials (3)(4)(5)(6)(7) and device architectures (8)(9)(10), and much work were devoted to understanding the working mechanism (11,12). Through suppressing nonradiative recombination and balancing carrier injection (13,14), the luminescence efficiency of the device has been significantly improved. Up to now, the peak external quantum efficiency (EQE) of perovskite light-emitting devices exceeded 20% (14)(15)(16)(17), which is comparable to organic LED (OLED) (18).…”

Section: Introductionmentioning

confidence: 99%

Highly stable hybrid perovskite light-emitting diodes based on Dion-Jacobson structure

et al. 2019

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Organic-inorganic hybrid halide perovskites are emerging as promising materials for next-generation light-emitting diodes (LEDs). However, the poor stability of these materials has been the main obstacle challenging their application. Here, we performed first-principles calculations, revealing that the molecule dissociation energy of Dion-Jacobson (DJ) structure using 1,4-bis(aminomethyl)benzene molecules as bridging ligands is two times higher than the typical Ruddlesden-Popper (RP) structure based on phenylethylammonium ligands. Accordingly, LEDs based on the DJ structure show a half-lifetime over 100 hours, which is almost two orders of magnitude longer compared with those based on RP structural quasi–two-dimensional perovskite. To the best of our knowledge, this is the longest lifetime reported for all organic-inorganic hybrid perovskites operating at the current density, giving the highest external quantum efficiency (EQE) value. In situ tracking of the film composition in operation indicates that the DJ structure was maintained well after continuous operation under an electric field.

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“…The trade‐off, however, is an increase in surface defects as shown by Chen et al. in their recent report, where trap‐assisted non‐radiative recombination increases exponentially with decreasing NC size ,. Moreover, thermal annealing causes the conglomeration of these NCs, adding to the formation of additional defects ,…”

Section: Figurementioning

confidence: 98%

Doping and Photon Induced Defect Healing of Hybrid Perovskite Thin Films: An Approach Towards Efficient Light Emitting Diodes

et al. 2019

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Here, we demonstrate a simple method to improve photoluminescence and electroluminescent properties of MAPbBr3 perovskite thin films by monovalent Cs cation doping and treatment with UV light. It is known that the intermediate species of lead halides, which limits the photoluminescence quantum yield (PLQY) of perovskite thin films, are formed due to the presence of an organic polar solvent. In such cases, coalescence of nanocrystals is unavoidable when the thin‐films are thermally annealed to remove the intermediate phases and solvent residues. We find that PbBr2(DMSO)x complexes can effectively tune the morphology, grain boundary, PLQY, and non‐radiative loss of perovskite thin films under UV light irradiation. Upon UV exposure, highly uniform MA0.87Cs0.13PbBr3 ultra‐thin (45 nm) films with a full surface coverage of neatly packed nanocrystallites are obtained. When these films are integrated into electroluminescent devices, a current efficiency (CE) of 18.71 Cd/A and an external quantum efficiency (EQE) of 5.63% are observed for green perovskite‐based light emitting diodes (PeLEDs). These values of CE and EQE are respectively thirty‐four and forty‐three times higher than those achieved in pure MAPbBr3 based devices.

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Recombination Dynamics Study on Nanostructured Perovskite Light‐Emitting Devices

Cited by 108 publications

References 52 publications

Low Roll‐Off Perovskite Quantum Dot Light‐Emitting Diodes Achieved by Augmenting Hole Mobility

Low Roll‐Off Perovskite Quantum Dot Light‐Emitting Diodes Achieved by Augmenting Hole Mobility

Highly stable hybrid perovskite light-emitting diodes based on Dion-Jacobson structure

Doping and Photon Induced Defect Healing of Hybrid Perovskite Thin Films: An Approach Towards Efficient Light Emitting Diodes

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