Chlorine Vacancy Passivation in Mixed Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes

Zheng, Xiaopeng; Yuan, Shuai; Liu, Jiakai; Yin, Jun; Yuan, Fanglong; Shen, Wan‐Shan; Yao, Kexin; Wei, Mingyang; Zhou, Chun; Song, Kepeng; Zhang, Binbin; Lin, Yuanbao; Hedhili, Mohamed N.; Wehbe, Nimer; Han, Yu; Sun, Hongtao; Lu, Zheng‐Hong; Anthopoulos, Thomas D.; Mohammed, Omar F.; Sargent, Edward H.; Liao, Liang‐Sheng; Bakr, Osman M.

doi:10.1021/acsenergylett.0c00057

Cited by 252 publications

(206 citation statements)

References 35 publications

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“…We also examine the spectral stability of our devices at a constant current density of 5 mA cm -2 (with initial luminance ranging from ~200 to ~600 cd m -2 for different devices). Although the operational lifetime is no better than those in previously reported blue PeLEDs (with T50 around 1~2 min) 8,11,12,20 , we observe no spectral shift even after 10 minutes of operation ( Supplementary Fig. 15).…”

Section: Resultscontrasting

confidence: 67%

“…Under the harsh operational condition, that is, with the bias larger than 6.5 V, distinct colour change is observable even in VAC-treated devices. We emphasize that in this case the current density is over mA cm -2 , which is far above normal working conditions of reported blue PeLEDs 11,14,20,25 . Notably, we observe abnormal plateau-like J-V characteristics during the voltage sweep at 6~6.5 V and severe PL quenching after the operation ( Supplementary Fig.…”

Section: Resultsmentioning

confidence: 60%

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Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

Karlsson¹,

Yi²,

Reichert³

et al. 2020

Preprint

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Bright and efficient blue emission is key to further development of metal halide perovskite light-emitting diodes. Although modifying bromide/chloride composition is straightforward to achieve blue emission, practical implementation of this strategy has been challenging due to poor colour stability and severe photoluminescence quenching. Both detrimental effects become increasingly prominent in perovskites with the high chloride content that is desired to produce blue emission. Here, we solve these critical challenges in mixed halide perovskites and demonstrate spectrally stable blue perovskite light-emitting diodes (PeLEDs) over a wide range of emission wavelengths from 490 to 451 nanometres. The emission colour is directly tuned by modifying the halide composition. Particularly, our blue and deep-blue PeLEDs based on three-dimensional perovskites show high EQE values of 11.0% and 5.5% with emission peaks at 477 and 467 nm, respectively. These achievements are enabled by a vapour-assisted crystallization technique, which largely mitigates local compositional heterogeneity and ion migration.

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Section: Resultscontrasting

confidence: 67%

Section: Resultsmentioning

confidence: 60%

Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

Karlsson¹,

Yi²,

Reichert³

et al. 2020

Preprint

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show abstract

“…I(T) is constant between 4.5 and ~100 K but decreases rapidly above 100 K. These data, in conjunction with the PLQY of ~30% at room temperature under these conditions, suggest that the PLQY between 4.5 and 100 K is close to 100%, as observed previously. 16,44 We interpret the temperature dependence in Fig. 3b as thermally assisted exciton dissociation.…”

mentioning

confidence: 90%

Coherent Spin Precession and Lifetime-Limited Spin Dephasing in CsPbBr₃ Perovskite Nanocrystals

et al. 2020

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Carrier spins in semiconductor nanocrystals are promising candidates for quantum information processing. Using a combination of time-resolved Faraday rotation and photoluminescence spectroscopies, we demonstrate optical spin polarization and coherent spin precession in colloidal CsPbBr 3 nanocrystals that persists up to room temperature. By suppressing the influence of inhomogeneous hyperfine fields with a small applied magnetic field, we demonstrate inhomogeneous hole transverse spin-dephasing times (! ! *) that approach the nanocrystal photoluminescence lifetime, such that nearly all emitted photons derive from coherent hole spins. Thermally activated LO phonons drive additional spin dephasing at elevated temperatures, but coherent spin precession is still observed at room temperature. These data reveal several major distinctions between spins in nanocrystalline and bulk CsPbBr 3 and open the door for using metal-halide perovskite nanocrystals in spin-based quantum technologies.

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“…[ 155 ] Therefore, ion migration occurs more drastically and has been observed in PNC‐based devices. [ 150,156–159 ] Despite research remaining limited regarding ion migration in PNC solar cells, this does not mean that ion migration is minor, as there is an obvious ion migration‐related hysteresis. [ 48,102,107 ] For example, the highest PCE achieved for PNC solar cells is 17.39% by reverse‐scanning, while only a low PCE of 11.46% has been achieved through forward scanning.…”

Section: Challengesmentioning

confidence: 99%

“…[ 160 ] Passivation of surface halide vacancies and crosslinking are promising techniques. [ 157–160 ]…”

Section: Challengesmentioning

confidence: 99%

Metal Halide Perovskite Nanocrystal Solar Cells: Progress and Challenges

et al. 2020

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ultrasonication methods, [22] solvothermal approaches, [23] microwave-assisted synthesis, [24] and mechanical grinding. [25] PNCs not only inherit perovskite properties, but also possess the features of nanomaterials, such as their size-confinement effect and ease of processing as a colloidal ink, making PNCs suitable for incorporation into various electronic devices and compatible with printing techniques. [19,26] Moreover, nanoscale perovskites exhibit superior phase stability, particularly for CsPbI 3 and FAPbI 3 , due to their lattice construction and large surface energy. [27,28] Compared with traditional II-VI and III-V semiconductor nanocrystals, PNCs also exhibit unique properties. [29-32] Firstly, facile synthesis with inexpensive precursors can be conducted at room temperature with PNCs without inert gas protection. PNCs also have a bandgap ranging from the ultraviolet to nearinfrared, through which they can be easily tuned by size management and composition adjustment. Furthermore, they exhibit narrow bandwidth emission (<100 meV) over the entire visible range. PNCs also exhibit a fluorescence quantum yield near unity without additional passivation due to the defect-tolerance effect. Finally, they also demonstrate negligible self-absorption and Förster resonance energy transfer. These remarkable characteristics make PNCs more favorable than their bulk counterparts and traditional semiconductor nanocrystals. Thus, PNCs have promising applications in light-emitting diodes (LEDs), [33] lasers, [34] photodetectors, [35,36] and solar cells. [28] In 2016, Luther et al. first used CsPbI 3 PNCs to fabricate solar cells using a layer-by-layer approach. [28] The solar cell exhibited an extremely high open-circuit voltage (V OC) of 1.23 V, which was ≈85% of the Shockley-Queisser (S-Q) limited V OC , and a high power conversion efficiency (PCE) of 10.77%. This value was comparable to those of state-of-the-art PbS nanocrystal solar cells, [37] indicating the potential of PNC solar cells. To date, the highest PCE achieved by PNC solar cells has reached 17.39%. [38] Though PCEs have shown rapid, significant improvements, they are still limited compared to solar cells fabricated by bulk perovskite materials. Moreover, most studies on PNC solar cells have only been reported over the past two years. Research on PNC solar cells is still in its infancy, leaving substantial room for further improvement. Herein, we review the progress in the field of PNC solar cells. This review starts with detailing the unique advantages of PNCs. Next, we analyze current factors limiting their performance and Perovskite nanocrystal (PNC) solar cells have attracted increasing interest in recent years because of their excellent optoelectronic properties and unique advantages, which distinguish them from conventional nanocrystals and their bulk counterparts. This emerging type of photovoltaic is promising but faces many challenges regarding commercialization. Therefore, a comprehensive review is presented on the recent progress and current ch...

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Chlorine Vacancy Passivation in Mixed Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes

Cited by 252 publications

References 35 publications

Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

Coherent Spin Precession and Lifetime-Limited Spin Dephasing in CsPbBr₃ Perovskite Nanocrystals

Metal Halide Perovskite Nanocrystal Solar Cells: Progress and Challenges

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Chlorine Vacancy Passivation in Mixed Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes

Cited by 252 publications

References 35 publications

Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

Mixed Halide Perovskites for High-Efficiency and Spectrally Stable Blue Light-Emitting Diodes

Coherent Spin Precession and Lifetime-Limited Spin Dephasing in CsPbBr3 Perovskite Nanocrystals

Metal Halide Perovskite Nanocrystal Solar Cells: Progress and Challenges

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Coherent Spin Precession and Lifetime-Limited Spin Dephasing in CsPbBr₃ Perovskite Nanocrystals