Why do the NCs have a much stronger ionic bond?

owing to the much stronger ionic bond, the K+-based perovskite NCs show considerably improved stability and reduced non-radiative recombination.

Why does the pristine perovskite film show a large RMS?

Due to a large number of organic ligands, the pristine perovskite film shows a large root-mean-square (RMS) roughness of 8.69 nm.

What is the effect of K+ on the structure of perovskite NCs?

Previous reports have shown that an alkali metal ion can be incorporated into the perovskite lattice.[30-32] X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements are performed to investigate the effects of K+ on the structural properties of the resulting NCs.

What is the effect of the charge injection on the LED device?

For an LED device, any unbalanced charge injection can cause charge accumulation at the perovskite interface, degrading the device performance.

What is the effect of K+ on the organic ligands?

With the introduction of K+, the typical peak intensity of organic ligands is reduced, indicating the reduction of organic ligands in the perovskites.

Why do blue perovskite films lag behind the red and green ones?

blue PeLEDs still lag behind the red and green ones due to the difficulty in fabricating an efficient and stable perovskite emissive layer and the lack of proper charge transport material to achieve the desirable device structure to reduce the charge injection barrier.[12]

What is the EQE of the blue perovskite NC?

With the incorporation of K+, the authors reduce not only the non-radiative recombination but also the amount of organic ligand in the resulting perovskite NCs.

How does the blue perovskite NC-LED achieve a state-of-?

through optimizing the device structure, the optimized blue perovskite NC-LED achieves a state-of-the-art EQE among the blue PeLEDs based on NCs.[12]

What is the effect of K+ on the surface of perovskite films?

It can be concluded that the introduction of a rational amount of K+ improves the surface morphology of CsPb(Br/Cl)3 NC films, whereas excessive K+ will degrade the surface morphology, resulting in a bumpy surface.

What is the reason for the higher current density in the perovskite films?

The much- higher current density in the K+-based LEDs also indicates the superior conductivity of the perovskite films due to the reduced insulating organic ligands.

How is the EQE of the perovskite NCs achieved?

With further optimization of the device structure to balance the charge injection, a spectrally stable and efficient blue PeLED with an EQE of 1.96 is achieved, which shows evident improvement compared with a control device.

What is the way to increase the PLQY of the LED?

As previously mentioned, further increasing the addition ratio x to 8.0% can yield higher PLQY; however, the poor surface morphology results in a slightly reduced performance.

What is the diffraction peak shift in the perovskite NCs?

No diffraction peak shift can be observed in the K+-based samples, suggesting that K+ remains outside the perovskite NCs rather than being incorporated into the perovskite lattice.

How long does the champion device have?

the champion device shows a typical T50 lifetime of 4.5 min, which is 2.62 times longer than that of the LED device based on the pristine NCs (Figure S10).

What is the PL lifetime of the perovskite NCs?

The fitted PL lifetime of the K+-based NCs is much- longer than that of pristine NCs, which indicates stronger radiative recombination.

Open AccessJournal Article10.1002/ADFM.201908760

Efficient and Spectrally Stable Blue Perovskite Light-Emitting Diodes Based on Potassium Passivated Nanocrystals

Fei Yang, +8 more

- 01 Mar 2020

- Advanced Functional Materials

- Vol. 30, Iss: 10, pp 1908760

166

TL;DR: In this article, the development of blue perovskite light-emitting diode (LED) has been studied for display and lighting applications in the past several years for their promising applications in displays and lighting.

Abstract: Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light-emitt ...

AI Agents for this Paper

Find similar papers on Google Scholar, PubMed and Arxiv
Write a critical review of this paper
Analyze citations of this paper to find unaddressed research gaps

Most frequently asked questions

1. What are the common long chain organic ligands used in blue perovskite?

the commonly used long chain organic ligands are amine and acid, which can result in the desorption of surface ligandsand defects due to the protonation process between acid and amine.

2. What are the contributions in "Efficient and spectrally stable blue perovskite light-emitting diodes based on potassium passivated nanocrystals" ?

In this paper, the use of perovskite nanoplatelets is proposed to improve the performance of blue PeLEDs, achieving a state-of-the-art performance.

3. What is the effect of reducing the organic ligands on the perovskit?

In addition, as the ionic KBr (or KCl) can be regarded as surface ligands capping the perovskite NCs, the longchain organic ligands are dramatically reduced, which is beneficial to the charge transport of the perovskite films.

4. What is the reason for the variation in the surface morphology of perovskite?

The variation in the surface morphology of films with different values of x can be attributed to the growth speed of NCs, where more K+ leads to faster growth.[41]

Table 2. Summarized the detail electrical output parameters of PeLEDs with different ETL and HTL.

Figure 3. a) PL and UV-Vis absorption spectra of perovskite NC solutions with different x value. Insets in the right display the corresponding perovskite solutions under daylight and 365 nm UV lamp. b) PLQY of perovskite NC solutions with different x value. c) PL decay spectra of pristine and K+-based (4.0% in terms of nominal K+ ratio) NCs.

Figure 4. a) Energy level diagram and b) device structure of the LED device. c) Current densityvoltage-luminance curves and d) EQE-luminance curve for LED device based on x=4.0%. e) EL spectra of LED based on x=4.0% driven at voltage of 3.2 V and inset shows the corresponding CIE coordination. f) EL spectra of the device driven at different voltage.

Figure 2. Zoomed in XPS spectra of pristine and K+-based (4.0% in terms of nominal K+ ratio) NCs: a) Br 3d, b) Cl 2p. The atomic ratio of c) O/Pb and d) N/Pb for pristine and K+-based (4.0% in terms of nominal K+ ratio) NCs. e) Schematic illustration of potassium passivation.

Table 1. Summarized the detail electrical output parameters of PeLEDs with different x value.

Figure 1. a) XRD patterns of perovskite films with different x value and standard XRD patterns of CsPbBr3 and CsPbCl3. b, c) TEM images of pristine and K+-based (4.0% in terms of nominal K+ ratio) NCs, the insets show the corresponding high-resolution TEM images. d, e) NCs size distribution diagrams of pristine and K+-based (4.0% in terms of nominal K+ ratio) NCs.

Citations

Journal Article•10.1021/ACSNANO.0C08903

State of the Art and Prospects for Halide Perovskite Nanocrystals.

Amrita Dey, +78 more

- 27 Jul 2021

- ACS Nano

TL;DR: A comprehensive review of metal-halide perovskite nanocrystals can be found in this article, where researchers having expertise in different fields (chemistry, physics, and device engineering) have joined together to provide a state-of-the-art overview and future prospects of metalhalide nanocrystal research.

...read moreread less

977

Journal Article•10.1038/S41566-021-00766-2

Suppression of temperature quenching in perovskite nanocrystals for efficient and thermally stable light-emitting diodes

Mingming Liu, +11 more

- 01 Mar 2021

- Nature Photonics

TL;DR: In this article, a fluorine post-synthesis treatment was applied to perovskite nanostructures to achieve a temperature independent emission efficiency of near unity and constant decay kinetics up to a temperature of 373 K.

...read moreread less

346

Journal Article•10.1002/ANIE.202104812

All-Inorganic Quantum-Dot LEDs Based on a Phase-Stabilized α-CsPbI 3 Perovskite

Ya-Kun Wang, +29 more

- 12 Jul 2021

- Angewandte Chemie

TL;DR: In this article, an inorganic ligand exchange was proposed to improve the phase stability of CsPbI3 perovskites and increase the thermal transport of the QD solids.

...read moreread less

266

Journal Article•10.1002/ADMA.202005570

High-Performance Blue Perovskite Light-Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi-2D Perovskite Layers.

Zhenwei Ren, +12 more

- 01 Jan 2021

- Advanced Materials

TL;DR: In this work, a bifunctional ligand of 4-(2-aminoethyl)benzoic acid (ABA) cation is strategically introduced into the perovskite to diminish the weak van der Waals gap between individual perovSkite layers for promoting coupled quasi-2D perovSKite layers.

...read moreread less

235

Journal Article•10.1038/s41578-022-00459-4

A roadmap for the commercialization of perovskite light emitters

Tae Hee Han, +5 more

- 04 Aug 2022

- Nature Reviews Materials

219

...

Expand

References

•Journal Article•10.1002/ADMA.201600064

Highly Efficient Perovskite Nanocrystal Light-Emitting Diodes Enabled by a Universal Crosslinking Method.

Guangru Li, +12 more

- 01 May 2016

- Advanced Materials

TL;DR: A new trimethylaluminum vapor-based crosslinking method to render the nanocrystal films insoluble is applied, coupled with the natural confinement of injected charges within the perovskite crystals, facilitates electron-hole capture and gives rise to a remarkable electroluminescence yield.

...read moreread less

850

•Journal Article•10.1038/S41467-018-05909-8

Color-stable highly luminescent sky-blue perovskite light-emitting diodes

Jun Xing, +17 more

- 30 Aug 2018

- Nature Communications

TL;DR: Perovskite light-emitting diodes show promising color tunability and device performance but suffer from emission color shift at higher driving voltages, so color stable sky-blue PeLEDs achieved by enhancing the phase monodispersity of quasi-2D perovskites thin films are reported.

...read moreread less

638

•Journal Article•10.1021/ACS.NANOLETT.6B04453

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites.

Connor G. Bischak, +6 more

- 30 Jan 2017

- Nano Letters

TL;DR: It is proposed that the localized strain induced by a single photoexcited charge interacting with the soft, ionic lattice is sufficient to promote halide phase separation and nucleate a light-stabilized, low-bandgap, ∼8 nm iodide-rich cluster.

...read moreread less

631

Journal Article•10.1021/ACS.NANOLETT.6B02772

Exciton-to-Dopant Energy Transfer in Mn-Doped Cesium Lead Halide Perovskite Nanocrystals

David Parobek, +6 more

- 02 Nov 2016

- Nano Letters

TL;DR: Observations indicate that CsPbX3 nanocrystals, possessing many superior optical and electronic characteristics, can be utilized as a new platform for magnetically doped quantum dots expanding the range of optical, electronic, and magnetic functionality.

...read moreread less

614

...

Expand

Efficient and Spectrally Stable Blue Perovskite Light-Emitting Diodes Based on Potassium Passivated Nanocrystals

Chat with Paper

AI Agents for this Paper

Most frequently asked questions

1. What are the common long chain organic ligands used in blue perovskite?

2. What are the contributions in "Efficient and spectrally stable blue perovskite light-emitting diodes based on potassium passivated nanocrystals" ?

3. What is the effect of reducing the organic ligands on the perovskit?

4. What is the reason for the variation in the surface morphology of perovskite?

5. Why do the NCs have a much stronger ionic bond?

6. Why does the pristine perovskite film show a large RMS?

7. What is the effect of K+ on the structure of perovskite NCs?

8. What is the effect of the charge injection on the LED device?

9. What is the effect of K+ on the organic ligands?

10. Why do blue perovskite films lag behind the red and green ones?

11. What is the EQE of the blue perovskite NC?

12. How does the blue perovskite NC-LED achieve a state-of-?

13. What is the effect of K+ on the surface of perovskite films?

14. What is the reason for the higher current density in the perovskite films?

15. How is the EQE of the perovskite NCs achieved?

16. What is the way to increase the PLQY of the LED?

17. What is the diffraction peak shift in the perovskite NCs?

18. How long does the champion device have?

19. What is the PL lifetime of the perovskite NCs?

Figures

Citations

State of the Art and Prospects for Halide Perovskite Nanocrystals.

Suppression of temperature quenching in perovskite nanocrystals for efficient and thermally stable light-emitting diodes

All-Inorganic Quantum-Dot LEDs Based on a Phase-Stabilized α-CsPbI 3 Perovskite

High-Performance Blue Perovskite Light-Emitting Diodes Enabled by Efficient Energy Transfer between Coupled Quasi-2D Perovskite Layers.

A roadmap for the commercialization of perovskite light emitters

References

Highly Efficient Perovskite-Quantum-Dot Light-Emitting Diodes by Surface Engineering

Highly Efficient Perovskite Nanocrystal Light-Emitting Diodes Enabled by a Universal Crosslinking Method.

Color-stable highly luminescent sky-blue perovskite light-emitting diodes

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites.

Exciton-to-Dopant Energy Transfer in Mn-Doped Cesium Lead Halide Perovskite Nanocrystals

Related Papers (5)

Nanocrystals of Cesium Lead Halide Perovskites (CsPbX3, X = Cl, Br, and I): Novel Optoelectronic Materials Showing Bright Emission with Wide Color Gamut

Anion-exchange red perovskite quantum dots with ammonium iodine salts for highly efficient light-emitting devices

Perovskite light-emitting diodes with external quantum efficiency exceeding 20 per cent

Quantum Dot Light-Emitting Diodes Based on Inorganic Perovskite Cesium Lead Halides (CsPbX3)

Bright light-emitting diodes based on organometal halide perovskite