Unravelling additive-based nanocrystal pinning for high efficiency organic-inorganic halide perovskite light-emitting diodes

Park, Min‐Ho; Jeong, Seong Mok; Seo, H.S.; Wolf, Christoph; Kim, Young-Hoon; Kim, Hobeom; Byun, Jinwoo; Kim, Sang Woo; Cho, Himchan; Lee, Tae‐Woo

doi:10.1016/j.nanoen.2017.10.012

Cited by 105 publications

(107 citation statements)

References 30 publications

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“…The bipolar transporting organic blend layer was found to improve the film morphology and reduce the pinhole density of the underlying perovskite layer, and also acted as a bipolar host for the perovskite emitter, improving charge injection from the HIL and ETL and charge balance in the EML. Also, Park et al used a solution of an electron transporting small molecule organic material (TPBI) dissolved in a nonpolar volatile solvent during the crystallization of the perovskite to reduce the perovskite crystal grain size and to improve electron injection into the perovskite EML (Figure d) . Moreover, a graded distribution of the electron transporting organic small molecules in the direction of the thickness of the film enhances electron transport to attain better charge balance in a device, resulting in an improved luminance and electroluminescent efficiency (≈8.79%) (Figure e).…”

Section: Interface Engineering In Perovskite Optoelectronic Devicesmentioning

confidence: 99%

Interface and Defect Engineering for Metal Halide Perovskite Optoelectronic Devices

et al. 2019

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Metal halide perovskites have been in the limelight in recent years due to their enormous potential for use in optoelectronic devices, owing to their unique combination of properties, such as high absorption coefficient, long charge‐carrier diffusion lengths, and high defect tolerance. Perovskite‐based solar cells and light‐emitting diodes (LEDs) have achieved remarkable breakthroughs in a comparatively short amount of time. As of writing, a certified power conversion efficiency of 22.7% and an external quantum efficiency of over 10% have been achieved for perovskite solar cells and LEDs, respectively. Interfaces and defects have a critical influence on the properties and operational stability of metal halide perovskite optoelectronic devices. Therefore, interface and defect engineering are crucial to control the behavior of the charge carriers and to grow high quality, defect‐free perovskite crystals. Herein, a comprehensive review of various strategies that attempt to modify the interfacial characteristics, control the crystal growth, and understand the defect physics in metal halide perovskites, for both solar cell and LED applications, is presented. Lastly, based on the latest advances and breakthroughs, perspectives and possible directions forward in a bid to transcend what has already been achieved in this vast field of metal halide perovskite optoelectronic devices are discussed.

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Section: Interface Engineering In Perovskite Optoelectronic Devicesmentioning

confidence: 99%

Interface and Defect Engineering for Metal Halide Perovskite Optoelectronic Devices

et al. 2019

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“…This additive can infiltrate into the grain boundaries at the top side of the resulted film, which passivates the interface defects and facilitates the electron injection thus meliorating the charge injection balance (Figure 4b). [83] The NCP technique was adopted solely or in combination with other techniques to ensure the controllability of the in situ fabrication.…”

Section: Nanocrystal Pinningmentioning

confidence: 99%

In Situ Fabricated Perovskite Nanocrystals: A Revolution in Optical Materials

Chang

Bai

Zhong

2018

Advanced Optical Materials

192

127

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in bulk halide perovskites, long carrier diffusion length, and an absorption range covering the visible solar spectrum, collectively enable the high performance of photo electricity conversion. Compared to the bulk materials, perovskite nanocrystals or quantum dots (usually denoted as PNCs or PQDs) show obvious excitonic features with enhanced photoluminescence (PL) properties due to the well-known size-dependent quantum confinement effects. [14][15][16][17] The combination of color saturated emissions, super high quantum yield (QY), as well as easy processing inspired the intensive exploration of PNCs as light emitters, which is now under spotlights in the field of optical materials.The first perspective aim of PNCs is to alternate the state-of-the-art CdSe or InP quantum dots (QDs) as new generation luminescence materials. [18,19] As shown in Figure 1, these QD materials have been well demonstrated to be potential functional components for photonic and optoelectronic applications, and are currently on the way to industrialization. [20][21][22][23] Specifically, QDs can be employed as fluorescence labels, [24] laser gain media, [25] LED phosphors, [26] and down-shifting films for LCD backlights. [27,28] They can also be processed into thin film for optoelectronic devices including solar cells, [29] photodetectors, [30,31] transistors [32] and LEDs. [33] The PNCs outcompete these conventional QDs in terms of narrower full width at half maximum (FWHM) and low fabrication cost, but most importantly, the ease of in situ preparation. [34,35] Herein, this progress report highlight the developments of in situ fabricated PNCs.Colloidal semiconductor QDs are typically synthesized ex situ in flasks by hot injection method, stabilized by surface ligands. [36][37][38][39] To incorporate such solution based materials into applications usually requires purification, redispersion and surface engineering. For instance, ligand exchange is often employed to disperse QDs into aimed solvent, inducing defects that inevitably derogating the PLQYs. [40] Moreover, the organic ligands themselves also suffer from the risk of disabsorbing, reducing the stability of the QDs and thus the final devices. [41] Because halide perovskite are ionic compounds that can be well dissolved into polar solvents, PNCs can be fabricated through either ex situ routes in flask or in situ strategies on substrates. The in situ fabricated PNCs are adaptable to devices integration due to their scalable and low-cost manufacturing. In this regard, more and more efforts have been made in terms of the controlling synthesis, physical properties and device applications of PNC materials.After over 30 years of development, colloidal quantum dots have now become mature luminescent materials in photonic and optoelectronic operations and start to hit the market. The emerging perovskite nanocrystals are expected to promote large-scale commercialization due to their superior optical properties as well as low cost and easy fabrication. This progress report is focused on the...

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“…The perovskite materials show that they have tremendous prospects in optoelectronic devices because of their superior optoelectronic properties. [1][2][3][4][5] However, organic-inorganic hybrid perovskite materials are more easily degraded in air, which leads to a decrease of device stability. In contrast, all-inorganic cesium-lead halide perovskite (CsPbX 3 , X ¼ Cl, Br, I) has been proven to have better stability and excellent photoelectric properties, such as high colour purity with narrow spectral width (full width at half maximum, FWHM, of z20 nm), high absorption coefficients, long diffusion length and tunability of the band gap.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, all-inorganic cesium-lead halide perovskite (CsPbX 3 , X ¼ Cl, Br, I) has been proven to have better stability and excellent photoelectric properties, such as high colour purity with narrow spectral width (full width at half maximum, FWHM, of z20 nm), high absorption coefficients, long diffusion length and tunability of the band gap. [5][6][7][8][9] Hence, the investigation of all-inorganic cesium-lead halide perovskite may lay the foundation for the development of highperformance and stable perovskite light-emitting diodes. 10 Although all-inorganic perovskite has unique advantages in heat resistance and environmental adaptability which enhance the stability of devices, the preparation process is difficult to master accurately.…”

Section: Introductionmentioning

confidence: 99%

Improved photoelectric performance of all-inorganic perovskite through different additives for green light-emitting diodes

Yang

et al. 2019

RSC Adv.

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The exceptional optical and electronic properties of all-inorganic cesium lead bromide (CsPbBr 3 ) perovskite make it an ideal new optoelectronic material, but low surface coverage limits its performance. The morphological characteristics of thin films have a great influence on the performance of perovskite light emitting diodes, especially at low coverage, and an inhomogeneous surface will lead to current leakage.To tackle this problem, the widespread adoption of composite layers including polymers poly(ethylene oxide) (PEO) and organic insulating poly(vinylpyrrolidone) (PVP) and all-inorganic perovskites is an effective way to increase the surface coverage and uniformity of perovskite films and improve the performance of perovskite light emitting devices. In our work, the perovskite thin films are investigated by using PEO and PVP dual additives, and the optimized CsPbBr 3 -PEO-PVP LED with maximum luminance, current efficiency, and external quantum efficiency of 2353 cd m À2 (at 7.2 V), 2.14 cd A À1 (at 6.5 V) and 0.85% (at 6.5 V) was obtained. This work indicates that the method of using additives is not only the key to enhancing the quality of perovskite thin film, but also the key to achieving a higher performance perovskite LED.

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Unravelling additive-based nanocrystal pinning for high efficiency organic-inorganic halide perovskite light-emitting diodes

Cited by 105 publications

References 30 publications

Interface and Defect Engineering for Metal Halide Perovskite Optoelectronic Devices

Interface and Defect Engineering for Metal Halide Perovskite Optoelectronic Devices

In Situ Fabricated Perovskite Nanocrystals: A Revolution in Optical Materials

Improved photoelectric performance of all-inorganic perovskite through different additives for green light-emitting diodes

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