Saturated Red Light-Emitting Copolymers of Poly(aryleneethynylene)s with Narrow-Band-Gap (NBG) Units: Synthesis and Luminescent Properties

We report here on the utilization of variable band gap conjugated polymers for optoelectronic redox applications comprising organic photovoltaics, color tunable light emitting diodes, and electrochromics. For the evaluation of morphology in photovoltaicdevices, atomic force microscopy, and optical microscopy provided direct visualization of the blend film structure. The evolution of the morphology in two and three component blends incorporating poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenlenevinylene] (MEH-PPV), poly(methylmethacrylate) (PMMA), and [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) was investigated. It was found that while insulating PMMA can be used to modulate the phase separation in these blends, a bicontinuous network of donor and acceptor was required to achieve the best device results. Similarily, a MEH-PPVcopolymer with a decreased conjugation length has been used for investigating inter- and intramolecular photoinduced charge transfer in the presence of PMMA and PCBM.We fabricated MEH-PPV/PCBM solar cells that have power conversion efficiencies up to 1.5% with a range of 0.7–1.5%, dependent on the nature of the MEH-PPV used. This further indicates that in addition to blend morphology, polymer structure is critical for optimizing device performance. To this end, the concept of an ideal donor for photovoltaic devices based on poly[2,5-di(3,7-dialkoxy)-cyanoterephthalylidene] is described and two donor-acceptor polymers based on cyanovinylene (CNV) and dioxythiophene are discussed as representative examples of soluble narrow band gap polymers synthesized in our group. For light emitting applications, utilization of two blue emitting conjugated polymers poly (9,9-dioctylfluorene) (PFO) and poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,ethyl-3,6-carbazole)] (PFH-PEtCz)is presented for a color tunable polymer light emitting diode that emits orange, green, and blue light with a voltage range of 7–10 V as a function of the total conjugated polymer content in PMMA and is attributed to the phase separation between the conjugated polymers. Finally, the narrow band gap conjugated polymer, poly[bis(3,4-propylenedioxythiophene-dihexyl)]-cyanovinylene has been characterized for its electrochromic properties, illustrating the multifunctional nature of variable band gap conjugated polymers.

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Narrow-Band-Gap Polymer Photovoltaic Materials Synthesis and Photovoltaic Research

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.273.468 ◽

2013 ◽

Vol 273 ◽

pp. 468-472

Author(s):

Yong Sen Wei

Keyword(s):

Band Gap ◽

Energy Gap ◽

Narrow Band ◽

Field Effect Transistors ◽

Materials Synthesis ◽

Photovoltaic Properties ◽

Light Emitting ◽

Photovoltaic Materials ◽

Photovoltaic Characteristics ◽

Photovoltaic Material

In recent years, research of the narrow-band-gap polymer photovoltaic (PV) materials in the field of light-emitting diodes, field effect transistors, solar cells and sensors has made tremendous progress and its application becomes more widely. In order to obtain a better performance of the photovoltaic material, in the process of design the polymer, we must consider the spectral range, the energy gap, the balance between the LUMO and HOMO level. Through the analysis of the narrow-band-gap polymers, this paper described the synthesis of the photovoltaic material, and detailed analyzes its photovoltaic characteristics. This paper introduces the double bonds to combine DTBT receptors and different electron donor, to synthesize new narrow-band-gap polymer photovoltaic materials with photovoltaic properties.

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Preparation and luminescent properties of a rare earth borate red light-emitting material

Materials Science-Poland ◽

10.2478/msp-2018-0057 ◽

2018 ◽

Vol 36 (3) ◽

pp. 359-363

Author(s):

B. Ying ◽

W.G. Sheng

Keyword(s):

Crystal Structure ◽

Rare Earth ◽

Solution Method ◽

Water Solution ◽

Red Light ◽

Luminescent Properties ◽

Spontaneous Crystallization ◽

Light Emitting ◽

Structure Morphology ◽

Rare Earth Borate

AbstractA new hydrated rare earth borate K2O·CaO·4B2O3·12H2O:Eu was prepared by water solution method. The crystal structure, morphology, luminescence properties were investigated via XRD, IR, TG-DSC and SEM, respectively, and it was shown that one single crystal was obtained via spontaneous crystallization. The luminescent properties were also investigated by F-4600 spectrophotometer.

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Synthesis and luminescent properties of novel red-emitting M7Sn(PO4)6:Eu3+(M= Sr,Ba) phosphors

Processing and Application of Ceramics ◽

10.2298/pac1801008f ◽

2018 ◽

Vol 12 (1) ◽

pp. 8-12

Author(s):

Guo Feng ◽

Weihui Jiang ◽

Jianmin Liu ◽

Cong Li ◽

Quan Zhang

Keyword(s):

Solid State ◽

Solid State Reaction ◽

Red Light ◽

Luminescent Properties ◽

Solid State Reaction Method ◽

Formula Unit ◽

Conventional Solid State Reaction ◽

Light Emitting ◽

Reaction Method ◽

Uv Leds

Novel Eu3+-activated M7Sn(PO4)6 (where M = Sr, Ba) red-emitting phosphors were synthesized via conventional solid-state reaction method at 1200 ?C for 2 h. The luminescence properties of the prepared samples and quenching concentration of Sr7-xSn(PO4)6 :xEu3+ and Ba7-xSn(PO4)6 :xEu3+ were investigated. These phosphors can be efficiently excited by UV (395 nm) and visible blue (465 nm) light nicely matching the output wavelengths of the near-UV LEDs and InGaN blue LED chips and emit the red light. The critical concentrations of the Eu3+ activator were found to be 0.175mol and 0.21mol per formula unit for Sr7-xSn(PO4)6 :xEu3+ and Ba7-xSn(PO4)6 :xEu3+, respectively. The M7-xSn(PO4)6 :xEu3+ (M = Sr, Ba) phosphor may be a good candidate for light-emitting diodes application.

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