Energy and Charge Dual Transfer Engineering for High‐Performance Green Perovskite Light‐Emitting Diodes

An, Hee Ju; Baek, Sung Doo; Kim, Do Hoon; Myoung, Jae‐Min

doi:10.1002/adfm.202112849

Cited by 27 publications

(18 citation statements)

References 42 publications

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“…This phenomenon is more prominent for LEDs because they work under a much higher electric field due to their thinner perovskite active layer and higher working voltage than those of solar cells. [42,43] To test the ion migration and any subsequent degradation in the perovskite films, the PL image of the films (glass/PEDOT:PSS/perovskite) was captured under an electric bias of 0.1 V µm −1 . The test setup is illustrated in Figure S6 (Supporting Information).…”

Section: Electrical Propertiesmentioning

confidence: 99%

Super‐Bright Green Perovskite Light‐Emitting Diodes Using Ionic Liquid Additives

et al. 2023

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size of the CsPbBr 3 film, as large crystallites reduce the probability of radiative recombination in the perovskite crystallites, resulting in poor light emission. [9] However, small crystallites have large crystallite boundaries and high surfacetrap density. Thus, passivating surface traps is an integral part of the fabrication of high-performance PeLEDs. [10,11] This passivation is performed mostly by using different kinds of organic or inorganic additives that simultaneously affect the film growth and passivate the perovskite surfaces as a capping ligand. [12][13][14] Another major issue with perovskite materials is their high ionic activity and bias-dependent ion migration. [13] Severe ion migration can create numerous ionic vacancies, which subsequently results in lattice collapse. Ion migration is also responsible for the spectral shift in the wavelength emitted by PeLEDs, particularly for mixed-anion and mixed-cation PeLEDs. [4,5] This can be prevented by confining the ions in small crystallites using capping ligands. [15][16][17] However, most of these long-chain ligands are electrically insulating in nature which leaves a nonconducting sheath around the perovskite crystallites and thus hindering the electrical connection between the perovskite emissive and charge transport layers. [18] In addition, a high EQE was achieved only at low current densities in the range of 1-100 mA cm −2 . [13] At higher current densities, different phenomena, such as Auger recombination, imbalance in charge injection, and Joule heating, collectively lead to an efficiency roll-off. Thus, the working current density for stable PeLED operation remains low, limiting their luminance to less than 1 × 10 5 cd m −2 , whereas organic LEDs (OLED) and quantum dot LEDs can achieve more than 6 × 10 5 cd m −2 luminance. [19] Overpowering this roll-off and improving the working current density are important for achieving a high luminance with a sufficiently high EQE in PeLEDs for commercial applications. Additionally, delivering a high injection current that overcomes the lasing threshold would help the realization of electrically pumped perovskite laser diodes in the future. [20] However, while the EQEs of PeLEDs, especially green-emitting ones, have rapidly increased in recent years, there is still much to be explored for brightness enhancement.In this study, we have demonstrated a high-luminance green PeLED by controlling the CsPbBr 3 film morphology and its band energy levels using a room-temperature ionic liquid (IL) additive. ILs have been explored in perovskite solar cells before, Halide perovskites have potential for use in next-generation low-cost, highefficiency, and highly color-pure light-emitting diodes (LED) that can be used in various applications, such as flat and flexible displays and solid-state lighting. However, they still lag behind other mature technologies, such as organic LEDs and inorganic LEDs, in terms of performance, particularly brightness. This lag is partly due to the insulating nature of the long-chain organ...

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Section: Electrical Propertiesmentioning

confidence: 99%

Super‐Bright Green Perovskite Light‐Emitting Diodes Using Ionic Liquid Additives

et al. 2023

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“…[24] For instance, the introduction of co-HTLs (e.g., the combination of PVK with small-molecule HTLs) can be an effective strategy to enhance the device's performance. [53] To provide further evidence for the significance of the chirality of ligands, D-phenylalanine methyl ester hydrochloride (D-PMeCl) is also found to be beneficial for device's performance. For example, the EQE of D-PMeCl-modified PeLEDs is 10.42%, which is 2.4-fold higher than that of PVK-based pristine PeLEDs, as shown in Figure S14 (Supporting Information).…”

Section: Enhancement Of Charge Balancementioning

confidence: 99%

Manipulation of Charge Dynamics for Efficient and Bright Blue Perovskite Light‐Emitting Diodes with Chiral Ligands

Zhang

Guo

et al. 2023

Advanced Materials

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Perovskite light‐emitting diodes (PeLEDs) emerge as a promising class of optoelectronic devices for next‐generation displays and lighting technology. However, the performance of blue PeLEDs lags far behind that of their green and red counterparts, including the unachieved trade‐off between high efficiency and high luminance, severe efficiency roll‐off, and unsatisfactory power efficiency. Here, a multi‐functional chiral ligand of L‐phenylalanine methyl ester hydrochloride is strategically introduced into quasi‐2D perovskites, which can effectively passivate defects, modulate the phase distribution, improve photoluminescence quantum yield, guarantee high‐quality film morphology, and enhance charge transport. Furthermore, ladder‐like hole transport layers are established, boosting charge injection and balance. The resultant sky‐blue PeLEDs (the photoluminescence peak is 493 nm and the electroluminescence peak is 497 nm) exhibit an external quantum efficiency of 12.43% at 1000 cd m−2 and a record power efficiency of 18.42 lm W−1, rendering that the performance is among the best blue PeLEDs.

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“…For example, an imbalance in charge injection, interface loss, and other factors can decrease the EQE of PeLEDs. [106][107][108][109][110] Therefore, the design and selection of the device structures play an essential role in the development of high-performance PeLEDs. In this section, we discuss recent advances in PeLEDs including device structures, light emission mechanisms, and charge transport layer materials.…”

Section: Perovskite-based Ledsmentioning

confidence: 99%

Materials, Device Structures, and Applications of Flexible Perovskite Light‐Emitting Diodes

Jang

Kim

et al. 2023

Adv Elect Materials

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The flexible type of displays, which can alter their shape freely (e.g., bendable or foldable displays) according to situational demands, is under an intense spotlight due to applications in human‐friendly mobile electronics. Among various types of light‐emitting diodes (LEDs), meanwhile, perovskite‐based LEDs (PeLEDs) have garnered particular attention in recent years as next‐generation optoelectronic devices due to their exceptional optical characteristics, such as high efficiency (up to theoretical limits), high color purity, wide color gamut over the entire visible range, and ultrathin form factor. By integrating perovskite materials on an ultrathin flexible substrate with a proper encapsulation layer, the flexible PeLEDs, which can conform to various curved surfaces and be stably operated in an ambient condition, have been developed. Here, recent advances of the flexible PeLEDs are reviewed. First, light‐emitting materials and device structures for the PeLEDs are introduced. Then, research progress on the flexible PeLEDs, either with and without the encapsulation layer are summarized. Next, some representative application examples of the flexible PeLEDs are briefly discussed. Finally, this review includes a brief discussion on future prospects.

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Energy and Charge Dual Transfer Engineering for High‐Performance Green Perovskite Light‐Emitting Diodes

Cited by 27 publications

References 42 publications

Super‐Bright Green Perovskite Light‐Emitting Diodes Using Ionic Liquid Additives

Super‐Bright Green Perovskite Light‐Emitting Diodes Using Ionic Liquid Additives

Manipulation of Charge Dynamics for Efficient and Bright Blue Perovskite Light‐Emitting Diodes with Chiral Ligands

Materials, Device Structures, and Applications of Flexible Perovskite Light‐Emitting Diodes

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