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Tuning photoluminescence of organic rubrene nanoparticles through a hydrothermal process.

Kim MS, Cho EH, Park DH, Jung H, Bang J, Joo J - Nanoscale Res Lett (2011)

Bottom Line: The light-emitting color distribution of the NPs was confirmed using confocal laser spectrum microscope.Filtered-up rubrene NPs treated at 170°C and 180°C exhibited blue luminescence due to the decrease of intermolecular excimer densities with the rapid increase in size.Variations in PL of hydrothermally treated rubrene NPs resulted from different size distributions of the NPs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-713, Korea. jjoo@korea.ac.kr.

ABSTRACT
Light-emitting 5,6,11,12-tetraphenylnaphthacene (rubrene) nanoparticles (NPs) prepared by a reprecipitation method were treated hydrothermally. The diameters of hydrothermally treated rubrene NPs were changed from 100 nm to 2 μm, depending on hydrothermal temperature. Photoluminescence (PL) characteristics of rubrene NPs varied with hydrothermal temperatures. Luminescence of pristine rubrene NPs was yellow-orange, and it changed to blue as the hydrothermal temperature increased to 180°C. The light-emitting color distribution of the NPs was confirmed using confocal laser spectrum microscope. As the hydrothermal temperature increased from 110°C to 160°C, the blue light emission at 464 to approximately 516 nm from filtered-down NPs was enhanced by H-type aggregation. Filtered-up rubrene NPs treated at 170°C and 180°C exhibited blue luminescence due to the decrease of intermolecular excimer densities with the rapid increase in size. Variations in PL of hydrothermally treated rubrene NPs resulted from different size distributions of the NPs.

No MeSH data available.


CLSM images. (a)-(d) CLSM images of the filtered-up pristine and HT rubrene NPs. (e)-(h) CLSM images of the filtered-down pristine and HT rubrene NPs. (i) Color distribution of the filtered-up pristine and HT NPs as a function of hydrothermal temperature. (j) Color distribution of the filtered-down pristine and HT NPs as a function of hydrothermal temperatures.
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Figure 5: CLSM images. (a)-(d) CLSM images of the filtered-up pristine and HT rubrene NPs. (e)-(h) CLSM images of the filtered-down pristine and HT rubrene NPs. (i) Color distribution of the filtered-up pristine and HT NPs as a function of hydrothermal temperature. (j) Color distribution of the filtered-down pristine and HT NPs as a function of hydrothermal temperatures.

Mentions: The evolution of PL characteristics of rubrene NPs through the hydrothermal process was confirmed by CLSM. Figure 5a-d and 5e-h are CLSM images for filtered-up and filtered-down rubrene NPs, respectively. For pristine NPs, the red (R), green (G), and blue (B) luminescence color distributions are 45.08%, 25.86%, and 29.06% for the filtered-up samples and 56.48%, 12.33%, and 31.19% for the filtered-down ones, respectively. Red luminescence dominated for both kinds of pristine NPs. These results are qualitatively consistent with PL characteristics shown in Figures 2b, 4a. The distribution of green luminescence for all filtered-up and filtered-down rubrene NPs were 18% to approximately 34% and 15% to approximately 26%, respectively, as shown in Figure 5i. As shown in Figure 5i, the distributions of red and blue luminescence abruptly changed for the HT-160 and HT-170 rubrene NPs, indicating the transition temperature for PL characteristics of HT rubrene NPs is 160°C to approximately 170°C. This transition temperature corresponds to the rapid variation in diameter of HT rubrene NPs, shown in Figure 3e. For filtered-up HT-180 rubrene NPs, blue luminescence increased to 78%, while that of red decreased to 18%, as shown in Figure 5i. For filtered-down rubrene NPs, blue luminescence increased from 31% in the pristine samples to 85% for the HT-180 ones, while that of red decreased from 56% in the pristine samples to 0% in the HT-180 ones. For both filtered-up and filtered-down HT-180 rubrene NPs, the dominance of blue luminescence agreed with the PL properties shown in Figure 4f.


Tuning photoluminescence of organic rubrene nanoparticles through a hydrothermal process.

Kim MS, Cho EH, Park DH, Jung H, Bang J, Joo J - Nanoscale Res Lett (2011)

CLSM images. (a)-(d) CLSM images of the filtered-up pristine and HT rubrene NPs. (e)-(h) CLSM images of the filtered-down pristine and HT rubrene NPs. (i) Color distribution of the filtered-up pristine and HT NPs as a function of hydrothermal temperature. (j) Color distribution of the filtered-down pristine and HT NPs as a function of hydrothermal temperatures.
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Related In: Results  -  Collection

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Figure 5: CLSM images. (a)-(d) CLSM images of the filtered-up pristine and HT rubrene NPs. (e)-(h) CLSM images of the filtered-down pristine and HT rubrene NPs. (i) Color distribution of the filtered-up pristine and HT NPs as a function of hydrothermal temperature. (j) Color distribution of the filtered-down pristine and HT NPs as a function of hydrothermal temperatures.
Mentions: The evolution of PL characteristics of rubrene NPs through the hydrothermal process was confirmed by CLSM. Figure 5a-d and 5e-h are CLSM images for filtered-up and filtered-down rubrene NPs, respectively. For pristine NPs, the red (R), green (G), and blue (B) luminescence color distributions are 45.08%, 25.86%, and 29.06% for the filtered-up samples and 56.48%, 12.33%, and 31.19% for the filtered-down ones, respectively. Red luminescence dominated for both kinds of pristine NPs. These results are qualitatively consistent with PL characteristics shown in Figures 2b, 4a. The distribution of green luminescence for all filtered-up and filtered-down rubrene NPs were 18% to approximately 34% and 15% to approximately 26%, respectively, as shown in Figure 5i. As shown in Figure 5i, the distributions of red and blue luminescence abruptly changed for the HT-160 and HT-170 rubrene NPs, indicating the transition temperature for PL characteristics of HT rubrene NPs is 160°C to approximately 170°C. This transition temperature corresponds to the rapid variation in diameter of HT rubrene NPs, shown in Figure 3e. For filtered-up HT-180 rubrene NPs, blue luminescence increased to 78%, while that of red decreased to 18%, as shown in Figure 5i. For filtered-down rubrene NPs, blue luminescence increased from 31% in the pristine samples to 85% for the HT-180 ones, while that of red decreased from 56% in the pristine samples to 0% in the HT-180 ones. For both filtered-up and filtered-down HT-180 rubrene NPs, the dominance of blue luminescence agreed with the PL properties shown in Figure 4f.

Bottom Line: The light-emitting color distribution of the NPs was confirmed using confocal laser spectrum microscope.Filtered-up rubrene NPs treated at 170°C and 180°C exhibited blue luminescence due to the decrease of intermolecular excimer densities with the rapid increase in size.Variations in PL of hydrothermally treated rubrene NPs resulted from different size distributions of the NPs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-713, Korea. jjoo@korea.ac.kr.

ABSTRACT
Light-emitting 5,6,11,12-tetraphenylnaphthacene (rubrene) nanoparticles (NPs) prepared by a reprecipitation method were treated hydrothermally. The diameters of hydrothermally treated rubrene NPs were changed from 100 nm to 2 μm, depending on hydrothermal temperature. Photoluminescence (PL) characteristics of rubrene NPs varied with hydrothermal temperatures. Luminescence of pristine rubrene NPs was yellow-orange, and it changed to blue as the hydrothermal temperature increased to 180°C. The light-emitting color distribution of the NPs was confirmed using confocal laser spectrum microscope. As the hydrothermal temperature increased from 110°C to 160°C, the blue light emission at 464 to approximately 516 nm from filtered-down NPs was enhanced by H-type aggregation. Filtered-up rubrene NPs treated at 170°C and 180°C exhibited blue luminescence due to the decrease of intermolecular excimer densities with the rapid increase in size. Variations in PL of hydrothermally treated rubrene NPs resulted from different size distributions of the NPs.

No MeSH data available.