UV-Green Emission from Organolead Bromide Perovskite Nanocrystals

Subscriber access provided by YORK UNIV

C: Physical Processes in Nanomaterials and Nanostructures

UV-Green Emission from Organolead Bromide Perovskite Nanocrystals Gopi C. Adhikari, Hongyang Zhu, Preston A. Vargas, and Peifen Zhu J. Phys. Chem. C, Just Accepted Manuscript • Publication Date (Web): 04 Jun 2018 Downloaded from http://pubs.acs.org on June 4, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

UV-Green Emission from Organolead Bromide Perovskite Nanocrystals Gopi C. Adhikari1, Hongyang Zhu*,1,2, Preston A. Vargas1, and Peifen Zhu*,1 1Department

of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104, United States

2School

of Physics and Electric Engineering, Linyi University, Linyi 276005, China

1 ACS Paragon Plus Environment

The Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 22

ABSTRACT: UV-green emitting MAPbBr3 nanocrystals were synthesized at room temperature, employing a cost-effective solution-based method. The size control of nanocrystals was achieved through varying ligand and solute concentrations, which resulted in a tunable bandgap and emission spectrum. The growth mechanism as well as the effect of ligand concentration on the structural and optical properties were studied in detail. The excitation spectra extended from the blue to the UV region. This indicates that these perovskites are promising photon down conversion materials which can combine with III-nitride UV/blue light-emitting diodes (LEDs) to emit white light. This work may bring III-nitride based white LEDs one step closer to widespread adoption in general illumination market because the large emission range that has been produced with the ligand assisted reprecipitation process is an important milestone on the path to justifying commercialization.


Page 3 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


I.

INTRODUCTION High-efficiency UV/blue LEDs have been realized in recent decades due to tremendous efforts devoted to the improvement of material quality and device structure.1-4 III-nitride based LEDs have been rapidly developing for modern lighting and display technology due to their superior efficiency compared to conventional lighting technologies.5 The low efficiency of green LEDs due to the fundamental phase separation issue in the high In-content InGaN quantum well layer is a barrier to obtaining white LEDs with high efficiency, color rendering index and chromaticity stability.6 The approach of coating UV LEDs with blue, green, and red phosphors, or coating blue LEDs with green and red phosphors is one of the most promising approaches to achieving highefficiency white LEDs with desired color quality.7-9 However, the limited material availability of the rare-earth elements used in the current generation of down conversion phosphors for LEDs increases the initial cost of white LEDs.10 Therefore, finding more common photon down conversion materials to couple with UV/blue LEDs is critical towards generating economical white light emission from LEDs. The key for photon down conversion materials is to acquire high quantum yield materials with emission in the blue, green, and red range while having a narrow full width at half maximum (FWHM). Organic-inorganic hybrid perovskites have been proven promising semiconductor materials for photovoltaic applications due to the tunable and direct band gap, high absorption coefficient, low carrier recombination rate, long charge diffusion length, good electrical conductivity, and earthabundant chemical components.11-25 A recent study showed that halide perovskites have narrower luminescence peaks, broader color gamut, lower cost and higher quantum yield 26 compared to typical Cd-based quantum dots (QDs). Perovskite QDs have been proven capable of greatly



Page 4 of 22

improving the performance of LEDs due to their unique properties.27-30 Therefore, halide perovskites have great potential for application in the next generation of light emitting devices. In this work, the narrow line-width emissions were obtained from MAPbBr3 nanocrystals under near UV/blue excitation by employing a low-cost solution-based method. The MAPbBr3 nanocrystals with various thicknesses and sizes were synthesized by precisely controlling the amount of ligand used in the reaction, which leads to tunable emission due to quantum confinement. A cheap and facile solution-processable method to tune the emission from violetgreen was demonstrated by varying the organic ligand and solute concentrations. Thus, this unique technique renders the use of chloride-based perovskites, most often used to emit blue light,31 redundant. This new process is the simplest synthesis method yet known. Thus, the bromide-based perovskites are promising photon down-conversion materials which can combine with III-nitride near UV/blue LED chips to generate white light emission. II.

EXPERIMETNAL METHOD

In a typical synthesis process, 0.05 g of MABr and 0.1 g of PbBr2 were added into the mixture of 1 mL of anhydrous N, N-Dimethylformamide (DMF), 17 mL of γ-Butyrolactone (GBL), and 30 μL of Octylamine under magnetic stirring. The solution became clear after the solids were dissolved completely. Then, this precursor solution was dropped into 10 mL of toluene with vigorous stirring at room temperature. The obtained colloidal solution was centrifuged at 5,000 rpm for 5 minutes to separate the aggregates of precipitates. The supernatant was collected in a clean vial and centrifuged again at 16,000 rpm for 15 minutes. The precipitate was collected by discarding the remaining supernatant. The obtained nanocrystals were then redispersed into toluene to obtain a nanocrystal suspension. The concentrations of solutes and ligand were varied to obtain a plethora of distinct sizes of nanocrystals, which resulted in emissions with different 4 ACS Paragon Plus Environment

Page 5 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


wavelengths from UV-green. Here, Octylamine was used as an organic ligand to control the growth of the NCs. GBL is used here as an anti-solvent, which facilitates easier precipitation of nanocrystals. The changing ligand and solute concentrations during the synthesis process are summarized in Table 1. Table 1. The amount of ligand, solutes and solvents used in the experiments. All Figures will be labeled by the same sample ID as noted below. Sample

Octylamine

MABr

PbBr2

DMF

GBL

ID

(μL)

(g)

(g)

(mL)

(mL)

(a)

0

0.05

0.10

4.5

0

(b)

30

0.05

0.10

1

17

(c)

60

0.05

0.10

2

34

(d)

90

0.05

0.10

2

34

(e)

105

0.05

0.10

2

34

(f)

120

0.05

0.10

2

34

Note that blue emission is commonly obtained from chloride-based perovskites.

31

Here, blue

emission was obtained from bromide-based perovskites. Bromide-based perovskites are cheaper to synthesize than that of chloride-based perovskites. The chemicals used for synthesizing chloride-based perovskite materials are comparatively expensive. Also, it takes more time to completely dissolve the solutes and the reaction requires significantly more heat to complete, thus making the replacement of chloride-based perovskites with bromide-based perovskites not only feasible, but preferable. The X-ray diffraction (XRD) measurements were carried out using Rigaku Smart Lab with Cu Kα1 radiation, λ =1.54 Aͦ operating at 40 kV and 44 mA to study the crystal structure of as-grown 5 ACS Paragon Plus Environment


Page 6 of 22

samples. These patterns were obtained at room temperature at an angular range (2θ) of 2o-70o with a step of 0.01o. Transmission Electron Microscopy (TEM) measurements were performed using a Hitachi H-7000 TEM at 75 kV to visually characterize the structure of the nanocrystals. Photoluminescence (PL) spectra were measured using a Spectro-Fluorophotometer (Shimadzu, RF-6000) with a xenon lamp as the excitation source. Absorption spectra were taken using a VARIAN Carry 50 Scan UV-Spectrophotometer in the range of 200-800 nm. III.

RESULTS AND DISCUSSION

The crystal structures of these samples were confirmed by XRD patterns, as shown in Figure 1. The diffraction peaks at ~14.9°, ~30.08°, and ~45.9° belong to MAPbBr3 perovskites. They are assigned to miller indices of (100), (200), and (300), respectively.22, 32 The strong diffraction peaks at low angles (below 10o) in Figure 1 are due to periodic superstructures.33 The peak present at

Figure 1. The XRD patterns of MAPbBr3 perovskites synthesized with various ligand

concentrations. The patterns are ordered such that the descending patterns are indicative of increasing ligand concentration. 6 ACS Paragon Plus Environment

Page 7 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


12.2o does not correspond to a perovskite structure, but arises as a result of MABr in the sample. 34 When the structure of the nanocrystals transitions to that of nanoplatelets, the superlattice behavior of these nanocrystals becomes relevant to the XRD patterns and begins to show stronger peaks than that of the individual perovskites themselves. This causes the main perovskite peaks to become substantially subdued in comparison to the superlattice peaks.

Figure 2. TEM images of MAPbBr3 nanocrystals synthesized at various ligand concentrations. The ligand concentration increases from (a) to (f). TEM images were also taken to investigate the effect of ligand and solute concentration on the structural properties of these samples. The transformation of the perovskite structure from 3D at low ligand concentration to quasi 2D with decreasing number of perovskite monolayers was observed when the concentration of ligand increased. Cube shaped MAPbBr3 crystals were obtained without adding Octylamine in the reaction as shown in Figure 2 (a). The dimensions of 7 ACS Paragon Plus Environment


Page 8 of 22

these crystals are ~200 nm. These large cubes appear in this synthesis type because this is the natural result of unrestricted crystal growth without the use of a ligand. With the relatively large growth because of the low-ligand environment, the quantum confinement effect would be marginal for these larger nanocubes and a clear band would be forming, which means that the emission wavelength is maximum. This also means emission line of this specific material has the lowest energy. The size of cube shaped MAPbBr3 crystals is significantly decreased with adding 30 μL of Octylamine and decreasing the solute concentration. The relatively restricted crystal growth due to an increased ligand concentration resulted in the formation nanocubes in Figure 2 (b) in comparison to the cubes in Figure 2 (a). The nanoplates in Figure 2 (c) were obtained by increasing the ligand concentration (60 μL) and decreasing the solute concentrations. A mixture of nanoplates and nanoplatelets in Figure 2 (d) was obtained when the ligand concentration was further increased (90 μL). Pure nanoplatelets were obtained when the amount of ligand used increased to 105 μL (Figure 2 (e)) and 120 μL (Figure 2 (f)). In Figures 2 (e) and (f), the nanoplatelets are stacking with an average spacing of 1.30 nm and 1.83 nm, length of 19.08 nm and 15.6 nm, and thickness of 2.28 nm and 1.73 nm, respectively. As the increasing ligand concentration forces the attached ligands to occupy more space between nanoplatelets, the thickness and the lateral dimension of nanoplatelets decreases. TEM images revealed periodic and well-ordered nanoplatelets, thus confirming the presence of super-lattices. In these images, some nanocrystals are brighter and some are darker. The darker places on the image indicate that there is overlapping between nanocrystals. The absorption spectra were measured to study the effect of ligand concentration on the band gap of those nanocrystals. The bandgap of this material was tuned by changing ligand and solute concentrations. This tuning was observed across the UV-visible range in the absorption spectra as 8 ACS Paragon Plus Environment

Page 9 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 3. Absorption Spectra of MAPbBr3 perovskites synthesized at various ligand concentrations. The ligand concentration increases from (a)-(f). The peak absorption wavelength is blue-shifted with an increase in the amount of ligand present in the reaction. shown in Figure 3, which indicates that the synthesized compounds have good absorption in the visible region. The peak in the absorption spectrum is attributed to exciton absorption. The peak is blue-shifted with increasing ligand and decreasing solute concentrations due to the quantum confinement effect. Quantum confinement is a change in optical and electronic properties that occurs when the dimension of nanocrystals is in the order of the exciton Bohr radius (the distance between electrons and holes) or less. This effect is also called size quantization. In this effect, the nanocrystals experience changes to their band structure due to the particle size being comparable to the spatial extent of the wave function. Then, the valance and conduction bands split into discrete and quantized energy levels due to the confinement of charge carriers. The corresponding band gaps were calculated from these absorption spectra and the obtained band gap is tunable from ∼2.31 to 2.83 eV. In Figure 4, the optical band gap has an approximately linear correlation with 9 ACS Paragon Plus Environment


Page 10 of 22

the ligand concentration. Thus, the band gap can be controllably tuned. This demonstrates a broadly variable band gap.

Figure 4. Band gap of MAPbBr3 perovskites as a function of the amount of ligand used in the

reaction. The linear fit shows that there is a clear correlation between ligand use and band gap. The emission spectra of MAPbBr3 nanocrystals are shown in Figure 5. The peak is red-shifted with decreasing ligand and increasing solute concentrations. When increasing the solute concentration, it allows for more reaction collision and therefore more growth. Allowing for more reaction collision leads to larger crystal growth and red-shifted emission because of diminishing quantum confinement. Conversely, increasing the ligand concentration causes the crystal growth to be throttled by the ligand, thereby resulting in blue-shifted emission due to a waxing quantum confinement effect.29, 35-37 This

occurs due to the ligands present in the final solution binding to the surface of the growing

nanocrystals as they develop, forcing a stop to growth once the ligands bind to all sides of the


Page 11 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 5. Emission Spectra of MAPbBr3 perovskites synthesized at various ligand concentrations. The emission profile becomes thinner with increasing ligand use. nanocrystals. The difference between the absorption and emission peak wavelengths is attributed to stokes’ shift. If we further increase the amount of ligand to 180 μL, the emission peak is further blue-shifted and limited to 407 nm as shown in Figure 5. The peak wavelength of the emission spectra of the nanocrystals as well as the bandgap with various ligand and solute concentrations are summarized in Table 2. The pure and sharp color spectra extended from UV to green (407-544 nm) with narrow linewidth emission. The narrow emission is demonstrated by the FWHM shown in Table 2. For pure blue and green emission, the FWHM are ~15 nm and ~21 nm, respectively. These values are significantly smaller than previously reported values.11, 38-40 This is attributed to the narrow size distribution of those nanocrystals and makes them exceptionally advantageous for optoelectronic applications. This narrow emission is characteristic of significantly strong and pure light.22, 41-43 11 ACS Paragon Plus Environment


Page 12 of 22

Table 2. Peak emission wavelength, FWHM and band gap with ligand amount. Sample Peak emission wavelength FWHM Band gap ID

(nm)

(nm)

(eV)

(a)

544

22

2.31

(b)

529

21

2.36

(c)

510

25

2.52

(d)

478

26

2.73

(e)

458

16

2.78

(f)

440

15

2.83

Note that UV-blue-green tunable emission was achieved from MAPbBr3 nanocrystals by simply .

adjusting the ligand concentration in this work. We will investigate the quantum yield and photoluminescence lifetimes of these nanocrystals in future work. Figure 6 shows the excitation spectra as related to the corresponding peak emission wavelengths. These spectra are broadband and almost the same shape. Broadband excitation indicates that these materials are favorable to be excited by a wide range of wavelengths. The highly tunable emission spectrum is also capable of covering a significant portion of the visible spectrum. Therefore, these perovskites can serve as photon down converters in III-nitride base white LEDs. There are some differences in the profile of the excitation spectra, which are due to quantum confinement. The nanoplatelets samples in Figures 6 (e) and (f) tend to have higher excitation behavior at the higher energy end of their spectra, while the nanoplates in Figures 6 (b) and (c) have an excitation preference for the middle of their spectra, and cubes in Figure 6 (a) have an excitation maximum at the lower energy bounds of their spectra. The blue shift in excitation spectra for nanocrystals experiencing quantum confinement occurs in a manner that is logically 12 ACS Paragon Plus Environment

Page 13 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 6. Excitation spectra of halide perovskites at various ligand concentrations. The predominantly broad-band profiles for the excitation show that this material is a reasonable partner to InGaN LEDs because InGaN emission is contained by MAPbBr 3 excitation. consistent with that of the effect of quantum confinement at the emission spectra. The quantization of energy levels at the bottom end of the conduction band artificially increases the band gap of the material, leading to blue-shifted emission. The same effect can be applied to the higher end of the conduction band, forcing photons to hit higher energy levels than normal to excite an electron in the perovskite, thereby causing the blue shift in the peak of the excitation spectra. Furthermore, the XRD and TEM data were used to study the stability of these kind of nanocrystals. These materials were kept in air at ambient conditions (humidity ∼ 50-60%) for 15 days. No changes were observed in The XRD patterns and TEM images as shown in Figure 7. This stability would allow for these perovskites to be layered onto optoelectronic devices without an inert-gas glovebox. 13 ACS Paragon Plus Environment


Page 14 of 22

i)

ii)

Figure 7. i) The XRD patterns and ii) TEM images of selected samples after 15 days in air. IV.

CONCLUSION

In summary, using a low-cost solution-based synthesis method, MAPbBr3 nanocrystals were found to have tunable emission (UV-green) and band gap by varying ligand and solute concentrations. The band gap energy of MAPbBr3 was found to have an approximately linear relationship with ligand concentration. The particular innovation here is the extraordinarily wide range of possible emission spectra that can now be obtained from organic-inorganic bromide perovskites. By taking the simple idea of ligand-assisted reprecipitation and substantially expanding the boundaries of ligand application to the synthesis of nanocrystals, the possible emission range of bromide perovskites has now expanded to encompass 54% of the visible range of wavelengths by only adjusting the direct amount of ligands. This extension of the re-precipitation process will allow for


Page 15 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


the production of highly versatile optoelectronic devices with a significantly lower amount of materials, thus justifying the hype behind the perovskite material.

AUTHOR INFORMATION Corresponding Authors *Email: [email protected]. Tel.: +1 (918) 631-5477. *Email: [email protected]. Tel.: +1 (918) 631-5125. Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS This work was supported by in part by The University of Tulsa through a Startup Fund, in part by The University of Tulsa Faculty Development Summer Fellowship, in part by the National Natural Science

Foundation

of

China

under

Grant

11774128,

and

in

part

by

Natural Science Foundation of Shandong Province under Grant ZR2018JL003. REFERENCES (1) Nakamura, S.; Krames, M. R. History of Gallium Nitride-Based Light-Emitting Diodes for Illumination. Proc. IEEE 2013, 101, 2211-2220. (2) Zhu, P.; Tansu, N. Effect of Packing Density and Packing Geometry on Light Extraction of III-Nitride Light-Emitting Diodes with Microsphere Arrays. Photonics Res. 2015, 3, 184191. (3) Zhu, P.; Tan, C.-K.; Sun, W.; Tansu, N. Aspect Ratio Engineering of Microlens Arrays in Thin-Film Flip-Chip Light-Emitting Diodes. Appl. Opt. 2015, 54, 10299-10303. 15 ACS Paragon Plus Environment


Page 16 of 22

(4) Zhu, P.; Tansu, N. Resonant Cavity Effect Optimization of III-Nitride Thin-Film Flip-Chip Light-Emitting Diodes with Microsphere Arrays. Appl. Opt. 2015, 54, 6305-6312. (5) Pust, P.; Schmidt, P. J.; Schnick, W. A Revolution in Lighting. Nat. Mater. 2015, 14, 454458. (6) Oh, J. H.; Oh, J. R.; Park, H. K.; Sung, Y. G.; Do, Y. R. New Paradigm of Multi-Chip White LEDs: Combination of an InGaN Blue LED and Full Down-Converted PhosphorConverted LEDs. Opt. Express 2011, 19, A270-A279. (7) Pust, P.; Weiler, V.; Hecht, C.; Tucks, A.; Wochnik, A. S.; Henss, A. K.; Wiechert, D.; Scheu, C.; Schmidt, P. J.; Schnick, W. Narrow-Band Red-Emitting Sr[LiAl3N4]:Eu2+ as a Next-Generation LED-Phosphor Material. Nat. Mater. 2014, 13, 891-6. (8) Zhu, P.; Zhu, H.; Qin, W.; Dantas, B. H.; Sun, W.; Tan, C.-K.; Tansu, N. Narrow-Linewidth Red-Emission Eu3+-Doped TiO2 Spheres for Light-Emitting Diodes. J. Appl. Phys. 2016, 119, 124305-8. (9) Zhu, P.; Wang, W.; Zhu, H.; Vargas, P.; Bont, A. Optical Properties of Eu 3+-Doped Y2O3 Nanotubes and Nanosheets Synthesized by Hydrothermal Method. IEEE Photonics J. 2018, 10, 4500210-10. (10) McKittrick, J.; Shea‐Rohwer, L. E.; Green, D. J. Review: Down Conversion Materials for Solid‐State Lighting. J. Am. Ceram. Soc. 2014, 97, 1327-1352. (11) Xing, J.; Yan, F.; Zhao, Y.; Chen, S.; Yu, H.; Zhang, Q.; Zeng, R.; Demir, H. V.; Sun, X.; Huan, A., et al. High-Efficiency Light-Emitting Diodes of Organometal Halide Perovskite Amorphous Nanoparticles. ACS Nano 2016, 10, 6623-30. (12) Aharon, S.; Etgar, L. Two Dimensional Organometal Halide Perovskite Nanorods with Tunable Optical Properties. Nano Lett. 2016, 16, 3230-3235. 16 ACS Paragon Plus Environment

Page 17 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(13) Xiao, Z.; Kerner, R. A.; Zhao, L.; Tran, N. L.; Lee, K. M.; Koh, T.-W.; Scholes, G. D.; Rand, B. P. Efficient Perovskite Light-Emitting Diodes Featuring Nanometre-Sized Crystallites. Nat. Photonics 2017, 11, 108-115. (14) Tan, Z.-K.; Moghaddam, R. S.; Lai, M. L.; Docampo, P.; Higler, R.; Deschler, F.; Price, M.; Sadhanala, A.; Pazos, L. M.; Credgington, D., et al. Bright Light-Emitting Diodes Based on Organometal Halide Perovskite. Nat. Nanotechnol. 2014, 9, 687-692. (15) Yuan, M.; Quan, L. N.; Comin, R.; Walters, G.; Sabatini, R.; Voznyy, O.; Hoogland, S.; Zhao, Y.; Beauregard, E. M.; Kanjanaboos, P., et al. Perovskite Energy Funnels for Efficient Light-Emitting Diodes. Nat. Nanotechnol. 2016, 11, 872-877. (16) Zhao, X. G.; Yang, J. H.; Fu, Y.; Yang, D.; Xu, Q.; Yu, L.; Wei, S. H.; Zhang, L. Design of Lead-Free Inorganic Halide Perovskites for Solar Cells via Cation-Transmutation. J. Am. Chem. Soc. 2017, 139, 2630-2638. (17) Zhu, H.; Fu, Y.; Meng, F.; Wu, X.; Gong, Z.; Ding, Q.; Gustafsson, M. V.; Trinh, M. T.; Jin, S.; Zhu, X. Y. Lead Halide Perovskite Nanowire Lasers with Low Lasing Thresholds and High Quality Factors. Nat. Mater. 2015, 14, 636-642. (18) Xujie Lu, W. Y., Quanxi Jia and Hongwu Xu Pressure-Induced Dramatic Changes in Organic– Inorganic Halide Perovskites. Chem. Sci. 2017, 6764-6776. (19) Yuan, Y.; Xu, R.; Xu, H.-T.; Hong, F.; Xu, F.; Wang, L.-J. Nature of the Band Gap ff Halide Perovskites ABX3 ( A = CH3 NH3 , Cs; B = Sn, Pb; X = Cl, Br, I): First-Principles Calculations. Chin. Phys. B. 2015, 24, 116302-5. (20) Akkerman, Q.; Gandini, M.; Di Stasio, F.; Rastogi, P.; Palazon, F.; Bertoni, G.; M. Ball, J.; Prato, M.; Petrozza, A.; Manna, L. Strongly Emissive Perovskite Nanocrystal Inks for HighVoltage Solar Cells. Nat. Energy 2016, 2, 16194-7. 17 ACS Paragon Plus Environment


Page 18 of 22

(21) Volonakis, G.; Filip, M. R.; Haghighirad, A. A.; Sakai, N.; Wenger, B.; Snaith, H. J.; Giustino, F. Lead-Free Halide Double Perovskites via Heterovalent Substitution of Noble Metals. J. Phys. Chem. Lett. 2016, 7, 1254-1259. (22) Ling, Y.; Yuan, Z.; Tian, Y.; Wang, X.; Wang, J. C.; Xin, Y.; Hanson, K.; Ma, B.; Gao, H. Bright Light-Emitting Diodes Based on Organometal Halide Perovskite Nanoplatelets. Adv. Mater. 2016, 28, 305-311. (23) Filipič, M.; Löper, P.; Niesen, B.; De Wolf, S.; Krč, J.; Ballif, C.; Topič, M. CH 3NH3PbI3 Perovskite / Silicon Tandem Solar Cells: Characterization Based Optical Simulations. Opt. Express 2015, 23, A263-A278. (24) Naphade, R.; Nagane, S.; Shanker, G. S.; Fernandes, R.; Kothari, D.; Zhou, Y.; Padture, N. P.; Ogale, S. Hybrid Perovskite Quantum Nanostructures Synthesized by Electrospray Antisolvent–Solvent Extraction and Intercalation. ACS Appl. Mat. Interfaces 2016, 8, 854861. (25) Khachatryan, H.; Kim, H.-P.; Lee, S.-N.; Kim, H.-K.; Kim, M.; Kim, K.-B.; Jang, J. Novel Method for Dry Etching CH3NH3PbI3 Perovskite Films Utilizing Atmospheric-HydrogenPlasma. Mater. Sci. Semicond. Process. 2018, 75, 1-9. (26) Xiao, Z.; Kerner, R. A.; Zhao, L.; Tran, N. L.; Lee, K. M.; Koh, T.-W.; Scholes, G. D.; Rand, B. P. Efficient Perovskite Light-Emitting Diodes Featuring Nanometre-Sized Crystallites. Nat Photon 2017, 11, 108-115. (27) Ken T. Shimizu; Helmut Bechtel, O. B. S., Marcel Böhmer, Edward Kang,; Danielle Chamberlin, a. J. B. Toward Commercial Realization of Quantum Dot Based White LightEmitting Diodes for General Illumination. Photonics Res. 2017, 5, A1-A6.


Page 19 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(28) Li, F.; You, L.; Nie, C.; Zhang, Q.; Jin, X.; Li, H.; Gu, X.; Huang, Y.; Li, Q. Quantum Dot White Light Emitting Diodes with High Scotopic/Photopic Ratios. Opt. Express 2017, 25, 21901-21913. (29) Zhang, F.; Zhong, H.; Chen, C.; Wu, X.-g.; Hu, X.; Huang, H.; Han, J.; Zou, B.; Dong, Y. Brightly Luminescent and Color-Tunable Colloidal CH3NH3PbX3 (X = Br, I, Cl) Quantum Dots: Potential Alternatives for Display Technology. ACS Nano 2015, 9, 4533-4542. (30) Schmidt, L. C.; Pertegás, A.; González-Carrero, S.; Malinkiewicz, O.; Agouram, S.; Mínguez Espallargas, G.; Bolink, H. J.; Galian, R. E.; Pérez-Prieto, J. Nontemplate Synthesis of CH3NH3PbBr3 Perovskite Nanoparticles. J. Am. Chem. Soc. 2014, 136, 850853. (31) Xing, J.; Yan, F.; Zhao, Y. W.; Chen, S.; Yu, H. K.; Zhang, Q.; Zeng, R. G.; Demir, H. V.; Sun, X. W.; Huan, A., et al. High-Efficiency Light-Emitting Diodes of Organometal Halide Perovskite Amorphous Nanoparticles. ACS Nano 2016, 10, 6623-6630. (32) Sadhanala, A.; Ahmad, S.; Zhao, B.; Giesbrecht, N.; Pearce, P. M.; Deschler, F.; Hoye, R. L.; Godel, K. C.; Bein, T.; Docampo, P., et al. Blue-Green Color Tunable Solution Processable Organolead Chloride-Bromide Mixed Halide Perovskites for Optoelectronic Applications. Nano Lett. 2015, 15, 6095-6101. (33) Yasutaka, N.; Katie, H. K.; Rui, T.; Ruipeng, L.; Zhongwu, W.; Ou, C. Nanocube Superlattices of Cesium Lead Bromide Perovskites and Pressure‐Induced Phase Transformations at Atomic and Mesoscale Levels. Adv. Mater. 2017, 29, 1606666-6. (34) Hyuck, H. J.; Ho, S. D.; Hyuk, I. S. Planar CH3NH3PbBr3 Hybrid Solar Cells with 10.4% Power Conversion Efficiency, Fabricated by Controlled Crystallization in the Spin‐ Coating Process. Adv. Mater. 2014, 26, 8179-8183. 19 ACS Paragon Plus Environment


Page 20 of 22

(35) Tanaka, K.; Takahashi, T.; Ban, T.; Kondo, T.; Uchida, K.; Miura, N. Comparative Study on the Excitons in Lead-Halide-Based Perovskite-Type Crystals CH3NH3PbBr3 /CH3NH3PbI3. Solid State Commun. 2003, 127, 619-623. (36) Manders, J. R.; Bera, D.; Qian, L.; Holloway, P. H., Quantum Dots for Displays and Solid State Lighting. In Materials for Solid State Lighting and Displays, Kitai, A., Ed. John Wiley & Sons, Ltd: Oxford, 2017; pp 31-90. (37) Pathak, S.; Sakai, N.; Wisnivesky Rocca Rivarola, F.; Stranks, S. D.; Liu, J.; Eperon, G. E.; Ducati, C.; Wojciechowski, K.; Griffiths, J. T.; Haghighirad, A. A., et al. Perovskite Crystals for Tunable White Light Emission. Chem. Mater. 2015, 27, 8066-8075. (38) Li, G.; Rivarola, F. W. R.; Davis, N. J. L. K.; Bai, S.; Jellicoe, T. C.; de la Peña, F.; Hou, S.; Ducati, C.; Gao, F.; Friend, R. H., et al. Highly Efficient Perovskite Nanocrystal LightEmitting Diodes Enabled by a Universal Crosslinking Method. Adv. Mater. 2016, 28, 35283534. (39) Hintermayr, V. A.; Richter, A. F.; Ehrat, F.; Döblinger, M.; Vanderlinden, W.; Sichert, J. A.; Tong, Y.; Polavarapu, L.; Feldmann, J.; Urban, A. S. Tuning the Optical Properties of Perovskite Nanoplatelets through Composition and Thickness by Ligand-Assisted Exfoliation. Adv. Mater. 2016, 28, 9478-9485. (40) Lipiński, M.; Socha, R.; Kędra, A.; Gawlińska, K.; Kulesza-Matlak, G.; Major, Ł.; Drabczyk, K.; Łaba, K.; Starowicz, Z.; Gwóźdź, K., et al. Studying of Perovskite Nanoparticles in PMMA Matrix Used As Light Converter for Silicon Solar Cell. Arch. Metall. Mater. 2017, 62, 17331-1739.


Page 21 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(41) Zhuang, S.; Ma, X.; Hu, D.; Dong, X.; Zhang, B. Air-Stable All Inorganic Green Perovskite Light Emitting Diodes Based on ZnO/ CsPbBr3/NiO Heterojunction Structure. Ceram. Int. 2017, 44, 4685-4688. (42) Li, G.; Tan, Z.-K.; Di, D.; Lai, M. L.; Jiang, L.; Lim, J. H.-W.; Friend, R. H.; Greenham, N. C. Efficient Light-Emitting Diodes Based on Nanocrystalline Perovskite in a Dielectric Polymer Matrix. Nano Lett. 2015, 15, 2640-2644. (43) Zhang, J.; Xiaokun, Y.; Deng, H.; Qiao, K.; Farooq, U.; Ishaq, M.; Yi, F.; Liu, H.; Tang, J.; Song, H. Low-Dimensional Halide Perovskites and Their Advanced Optoelectronic Applications. Nano-Micro Lett. 2017, 9, 36.



Page 22 of 22

TOC Graphic


UV-Green Emission from Organolead Bromide Perovskite Nanocrystals

Recommend Documents