Luminescence of heat-treated silicon-based polymers: promising materials for LED applications

Menapace, Ilaria; Mera, Gabriela; Riedel, Ralf; Erdem, Emre; Eichel, Rüdiger‐A.; Pauletti, Alberto; Appleby, G. A.

doi:10.1007/s10853-008-2882-9

Cited by 45 publications

(59 citation statements)

References 28 publications

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“…6 Menapace et al observed remarkable increase of dangling bonds during precursor pyrolysis up to 700 • C, and assigned them to carbon radicals. 30 In summary, bond cleavage of Si−CH 3 in the precursor and incorporation of sp 3 carbon in amorphous Si−O−C(−H) network is suggested to occur at the temperature range of 750-850 • C. First chemical step of such incorporation would be formation of Si−CH 2 −Si bridges. In the process, Si radicals capture neighborhood methyl groups effectively.…”

Section: Author(s) All Article Content Except Where Otherwise Notedmentioning

confidence: 96%

Investigation of photoluminescence of Si−O−C(−H) ceramics at an early stage of decarbonization by using high energy excitation

et al. 2014

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Si−O−C(−H) ceramics with reduced carbon contents were prepared by pyrolyzing polysiloxane particles in hydrogen at temperatures of 750, 800 and 850 °C. Under HeCd laser irradiation (325 nm), the obtained ceramics show broad spectra peaking at 400–415 nm. On the other hand, the excitation on the higher energy region by an ArF excimer laser (193 nm) induces new PL bands located at short wavelength region of 300 and 355 nm. Such high energy PL bands appear prominently in the ceramics synthesized at 750 °C, and are minor in ceramics synthesized at 800 and 850 °C.

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Section: Author(s) All Article Content Except Where Otherwise Notedmentioning

confidence: 96%

Investigation of photoluminescence of Si−O−C(−H) ceramics at an early stage of decarbonization by using high energy excitation

et al. 2014

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“…Although there have been reports on observation of PL from amorphous SiOC in the visibleultraviolet range, 38) strong PL from ZnO turns out to be dominant in the same photon-energy range for the present SiOCZnO composites.…”

Section: Resultsmentioning

confidence: 45%

“…29), 30) The polysiloxane-derived ceramics have many advantages as an encapsulating phase for ZnO: low processing temperature, 31),32) excellent mechanical strength 33)35) despite the amorphous phase, good thermochemical stability, 36),37) and luminescence. 38) This paper firstly reports a simple processing technique of encapsulated ZnO in porous polysiloxane-derived ceramic matrix. In addition, the effects of polysiloxane content and heat-treatment atmosphere on the porosity, flexural strength, and luminescence of the produced ceramics are investigated.…”

Section: )9)mentioning

confidence: 99%

Processing and structural characteristics of encapsulated ZnO in porous polysiloxane-derived ceramics

Kim

Eom

Kim

2011

J. Ceram. Soc. Japan

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A facile processing strategy based on a simple pressing and heat-treatment at 800°C in air or argon was successfully demonstrated for fabricating encapsulated ZnO in porous polysiloxane-derived ceramic matrix. The composite samples contain ZnO crystallites with wurtzite structure embedded in amorphous SiO 2 or SiOC matrix and have 5158% porosity depending on the starting polysiloxane content and heat-treatment atmosphere. For the samples heat-treated in air, the one with more ZnO content in the batch composition showed higher green-emission intensity as well as lower excitonic-emission intensity in photoluminescence (PL) spectrum compared to the one with less ZnO content. The result can be understood in terms of the amount of defects such as oxygen vacancies in the ZnO crystallites: the former has higher defect density than the latter. Raman spectra for the two samples support the interpretation. The samples heat-treated in argon exhibit weaker PL strength compared to the air-treated ones in the whole photon-energy range, attributable to the secondary phase (ZnSiO 3 ) formation.

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“…17) The reason for the black color of the PDC has been generally ascribed to the presence, in the ceramic structure of free carbon. 18) For this reason, optical properties of the PDCs, especially the polymerderived ternary SiCN materials are scarcely exploited since the absorption of visible light, which hinders their capability for the production of optical devices.…”

Section: )8)mentioning

confidence: 99%

“…dangling bonds) could be occurred. 9),10), 18) In the spectrum of 400°C-heat treated SDC, there were two excitation peaks and each excitation wavelengths lead to the different PL emission. At and below 700°C, the PL emission peaks located at longer wavelength (435473 nm) appeared with the crystallization process of ¡-SiC 2 N 4 phase by increasing the heat-treatment temperature, while those located at the shorter wavelengths (385401 nm) in the PL emission disappeared ( Table 1).…”

Section: Jcs-japanmentioning

confidence: 99%

Synthesis and characterization of luminescent properties of ceramics derived from polysilylcarbodiimides

Shimokawa

Fujiwara

Ionescu

et al. 2014

J. Ceram. Soc. Japan

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The luminescence properties related to the thermal polymer/ceramic conversion behavior of silicon dicarbodiimide {SDC, [Si(N=C=N) 2 ] n } have been investigated. SDC was synthesized by the non-oxidic solgel condensation reaction of silicon tetrachloride with bis(trimethylsilyl)carbodiimide. As-synthesized SDC showed no luminescence under UV light, while heat-treated SDC showed an appreciable photoluminescence (PL) and the maximum visible PL emission intensity was achieved by heat treatment at 400°C. Even after the heat treatment up to 970°C, the SDC preserved most of the N=C=N groups to keep whitish gray color without distinct free carbon formation, and emitted visible blue luminescence. The 400°C-heat treated SDC exhibited the intense luminescence excited at 281 and 379 nm wavelengths, while there was no PL emission excited by the N=C=N groupderived host absorption at 214 nm. The PL properties of the heat-treated SDCs could be correlated with their preservation of the local structure including N=C=N groups and defects formation during the heat treatment. Moreover, Eu 3+ -modified SDC was prepared by the same solgel method using Eu(III) chloride as the Eu 3+ -source. The results of Si NMR spectroscopic analyses revealed a complex formation between the Eu(III) chloride and bis(trimethylsilyl)carbodiimide. As a result, the Eu 3+ -modified SDC exhibited a characteristic PL red emission at around 600 nm attributed to the f-f-transition of Eu .

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Luminescence of heat-treated silicon-based polymers: promising materials for LED applications

Cited by 45 publications

References 28 publications

Investigation of photoluminescence of Si−O−C(−H) ceramics at an early stage of decarbonization by using high energy excitation

Investigation of photoluminescence of Si−O−C(−H) ceramics at an early stage of decarbonization by using high energy excitation

Processing and structural characteristics of encapsulated ZnO in porous polysiloxane-derived ceramics

Synthesis and characterization of luminescent properties of ceramics derived from polysilylcarbodiimides

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