Colloidal Nanocrystals Embedded in Macrocrystals: Methods and Applications

Adam, Marcus; Gaponik, Nikolai; Eychmüller, Alexander; Erdem, Talha; Soran‐Erdem, Zeliha; Demir, Hilmi Volkan

doi:10.1021/acs.jpclett.6b01699

Cited by 32 publications

(38 citation statements)

References 35 publications

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“…Obviously, the low QY in the solid state significantly limits the applicability of the polymers in the fabrication of optoelectronic devices as color converters. To find a solution to this problem, here we followed the approach of integrating light‐emitting materials into crystalline matrices . For this purpose, we embedded our polymers into NaCl, sucrose, and trehalose matrices.…”

Section: Resultsmentioning

confidence: 99%

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Erdem

Idris

Demir

et al. 2017

Macro Materials & Eng

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they pose significantly lower risks to environment and health compared to other optical materials such as cadmiumbased quantum dots [10] and lead-based perovskites. [11] Despite the potential of conjugated polymers, a decrease in the fluorescence quantum yield (QY) and a low emission stability in their solid state turn out to be an important bottleneck. These problems mainly arise from the changes in the polymer morphology upon film casting, which affects the inter and intrachain interactions. To decrease these interactions and consequently, achieve higher QYs in solid films, various approaches have been adopted including the utilization of nonradiative energy transfer to light-emitting polymers [12,13] and the incorporation of the polymers into inorganic nanoparticles. [14][15][16] Alternatively, chemical entities such as dendrones have been attached to the polymer backbone in order to weaken the π-π stacking.[17] Insulation of the conjugated polymer backbones via rotaxanation, which can be considered as threading the polymer chain using a macrocyclic ring, also steps forward as a promising solution. [18][19][20] In the literature, cyclodextrins and cucurbit[n]urils (CB[n]) have been shown to successfully isolate the polymer backbone leading to enhanced fluorescence QY. [21][22][23][24][25][26] For instance, our group has recently demonstrated fourfold increase in the fluorescence QY of poly(9,9′-bis(6″-(N,N,N-trimethylammonium)hexyl)fluorene-alt-co-thiophenelene) accompanied by blue-shifted fluorescence spectrum and prolonged fluorescence lifetime after threading with CB7. [27] Despite the improvements in the QY of polyrotaxane solutions, their solid films still suffered from decreased fluorescence QY. Therefore, a solution to maintain the fluorescence QY is of significant importance for their use in solid-state lighting.A possible solution to this problem might come from the research on the colloidal quantum dots, which similarly suffered from decreasing QYs in their solid films. Otto et al. [28] showed that the quantum dots in water can be successfully incorporated into crystalline salt matrices. Later, this approach was shown to improve the fluorescence QY, [29] and emission stability. [30,31] Moreover, this method was also extended to nonionic crystals including sucrose [32] and anthracene [33] and to quantum dots in nonpolar solvents [30,34] and applied in lightemitting diodes (LEDs) [31] and sensors. [35] Recently, our group has evaluated the potential of this technique by incorporating π-Conjugated Polyrotaaxanes π-Conjugated polymers suffer from low quantum yields (QYs) due to chainchain interactions. Furthermore, their emission in solid films is significantly quenched due to aggregation leading further decrease in QY. These are the two main issues of these materials hampering their widespread use in optoelectronic devices. To address these issues, here the backbone of poly(9,9′-bis (6″-(N,N,N-trimethylammonium)hexyl)fluorene-alt-co-thiophenelene) is isolated by threading with cucurbit[7]uril (CB7). Su...

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Section: Resultsmentioning

confidence: 99%

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Erdem

Idris

Demir

et al. 2017

Macro Materials & Eng

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“…[11][12][13][14][15][16] However,i fa n additional accessibility of the individual nanoparticles is still needed, as for instance in photocatalysis,animmobilization of the nanoparticles onto aporous scaffold material is desirable. Many optical and electronic properties of nanostructures,however,will depend on the precise control of the size, shape and composition.…”

Section: Embedding Nanoparticles Into Gelsmentioning

confidence: 99%

Modern Inorganic Aerogels

et al. 2017

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Essentially, the term aerogel describes a special geometric structure of matter. It is neither limited to any material nor to any synthesis procedure. Hence, the possible variety of materials and therefore the multitude of their applications are almost unbounded. In fact, the same applies for nanoparticles. These are also just defined by their geometrical properties. In the past few decades nano-sized materials have been intensively studied and possible applications appeared in nearly all areas of natural sciences. To date a large variety of metal, semiconductor, oxide, and other nanoparticles are available from colloidal synthesis. However, for many applications of these materials an assembly into macroscopic structures is needed. Here we present a comprehensive picture of the developments that enabled the fusion of the colloidal nanoparticle and the aerogel world. This became possible by the controlled destabilization of pre-formed nanoparticles, which leads to their assembly into three-dimensional macroscopic networks. This revolutionary approach makes it possible to use precisely controlled nanoparticles as building blocks for macroscopic porous structures with programmable properties.

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“…It has been proved that the incorporation of QDs into macrocrystal matrix can significantly enhance their thermal stability and photostability, such that these dot‐in‐matrix nanocomposites have been widely adopted in practical optoelectronic devices, such as light‐emitting diodes and displays . In this work, we fabricated the ligands‐free CsPbBr 3 nanocrystals embedded in Cs 4 PbBr 6 host matrix (CsPbBr 3 /Cs 4 PbBr 6 perovskite nanocomposites) by low temperature solution‐phase synthesis with the aim to enhance the temperature tolerance of CsPbBr 3 nanocrystals (see the Experimental Section for details).…”

mentioning

confidence: 99%

Solution‐Grown CsPbBr₃/Cs₄PbBr₆ Perovskite Nanocomposites: Toward Temperature‐Insensitive Optical Gain

Wang

et al. 2017

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With regards to developing miniaturized coherent light sources, the temperature-insensitivity in gain spectrum and threshold is highly desirable. Quantum dots (QDs) are predicted to possess a temperature-insensitive threshold by virtue of the separated electronic states; however, it is never observed in colloidal QDs due to the poor thermal stability. Besides, for the classical II-VI QDs, the gain profile generally redshifts with increasing temperature, plaguing the device chromaticity. Herein, this paper addresses the above two issues simultaneously by embedding ligands-free CsPbBr nanocrystals in a wider band gap Cs PbBr matrix by solution-phase synthesis. The unique electronic structures of CsPbBr nanocrystals enable temperature-insensitive gain spectrum while the lack of ligands and protection from Cs PbBr matrix ensure the thermal stability and high temperature operation. Specifically, a color drift-free stimulated emission irrespective of temperature change (20-150 °C) upon two-photon pumping is presented and the characteristic temperature is determined to be as high as ≈260 K. The superior gain properties of the CsPbBr /Cs PbBr perovskite nanocomposites are directly validated by a vertical cavity surface emitting laser operating at temperature as high as 100 °C. The results shed light on manipulating optical gain from the advantageous CsPbBr nanocrystals and represent a significant step toward the temperature-insensitive frequency-upconverted lasers.

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Colloidal Nanocrystals Embedded in Macrocrystals: Methods and Applications

Cited by 32 publications

References 35 publications

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Modern Inorganic Aerogels

Solution‐Grown CsPbBr₃/Cs₄PbBr₆ Perovskite Nanocomposites: Toward Temperature‐Insensitive Optical Gain

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Colloidal Nanocrystals Embedded in Macrocrystals: Methods and Applications

Cited by 32 publications

References 35 publications

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Highly Luminescent CB[7]‐Based Conjugated Polyrotaxanes Embedded into Crystalline Matrices

Modern Inorganic Aerogels

Solution‐Grown CsPbBr3/Cs4PbBr6 Perovskite Nanocomposites: Toward Temperature‐Insensitive Optical Gain

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Solution‐Grown CsPbBr₃/Cs₄PbBr₆ Perovskite Nanocomposites: Toward Temperature‐Insensitive Optical Gain