Band gap tuning of new light emitting conjugated polymers

2003 ◽  
Vol 21 (1-3) ◽  
pp. 199-203 ◽  
Author(s):  
Do-Hoon Hwang ◽  
Nam Sung Cho ◽  
Byung-Jun Jung ◽  
Hong-Ku Shim ◽  
Jeong-Ik Lee ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Band Gap ◽  
Light Emitting ◽  
Band Gap Tuning

Band-gap tuning of carbazole-containing donor–acceptor type conjugated polymers by acceptor moieties and π-spacer groups

Polymer ◽  
2008 ◽  
Vol 49 (1) ◽  
pp. 192-199 ◽  
Author(s):  
Tsuyoshi Michinobu ◽  
Kensuke Okoshi ◽  
Haruka Osako ◽  
Hiroe Kumazawa ◽  
Kiyotaka Shigehara
Keyword(s):  
Conjugated Polymers ◽  
Band Gap ◽  
Donor Acceptor ◽  
Band Gap Tuning

Variable band gap conjugated polymers for optoelectronic and redox applications

2005 ◽  
Vol 20 (12) ◽  
pp. 3188-3198 ◽  
Author(s):  
Young-Gi Kim ◽  
Barry C. Thompson ◽  
Nisha Ananthakrishnan ◽  
G. Padmanaban ◽  
S. Ramakrishnan ◽  
...  
Keyword(s):  
Phase Separation ◽  
Conjugated Polymers ◽  
Band Gap ◽  
Conjugated Polymer ◽  
Narrow Band ◽  
Acid Methyl Ester ◽  
Light Emitting ◽  
Donor And Acceptor ◽  
Color Tunable ◽  
Variable Band Gap

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.

Band-gap tuning of pendant polymers for organic light-emitting devices and photovoltaic applications

2011 ◽  
Vol 161 (9-10) ◽  
pp. 856-863 ◽  
Author(s):  
Akhil Gupta ◽  
Scott E. Watkins ◽  
Andrew D. Scully ◽  
Th. Birendra Singh ◽  
Gerard J. Wilson ◽  
...  
Keyword(s):  
Band Gap ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Photovoltaic Applications ◽  
Organic Light Emitting Devices ◽  
Band Gap Tuning

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

Color Variable Bipolar/AC Light-Emitting Devices Based on Conjugated Polymers

1997 ◽  
Author(s):  
Y. Z. Wang ◽  
D. D. Gebler ◽  
D. K. Fu ◽  
T. M. Swager ◽  
A. J. Epstein
Keyword(s):  
Conjugated Polymers ◽  
Light Emitting ◽  
Light Emitting Devices

scholarly journals Encapsulated Passivation of Perovskite Quantum Dot (CsPbBr3) Using a Hot-Melt Adhesive (EVA-TPR) for Enhanced Optical Stability and Efficiency

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 419
Author(s):  
Saradh Prasad ◽  
Mamduh J. Aljaafreh ◽  
Mohamad S. AlSalhi ◽  
Abeer Alshammari
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Surface Defects ◽  
Optoelectronic Devices ◽  
Ethylene Vinyl Acetate ◽  
Light Emitting ◽  
Optical Stability ◽  
Perovskite Quantum Dots ◽  
Polymer Light Emitting Diodes ◽  
Hot Melt

The notable photophysical characteristics of perovskite quantum dots (PQDs) (CsPbBr3) are suitable for optoelectronic devices. However, the performance of PQDs is unstable because of their surface defects. One way to address the instability is to passivate PQDs using different organic (polymers, oligomers, and dendrimers) or inorganic (ZnS, PbS) materials. In this study, we performed steady-state spectroscopic investigations to measure the photoluminescence (PL), absorption (A), transmission (T), and reflectance (R) of perovskite quantum dots (CsPbBr3) and ethylene vinyl acetate/terpene phenol (1%) (EVA-TPR (1%), or EVA) copolymer/perovskite composites in thin films with a thickness of 352 ± 5 nm. EVA is highly transparent because of its large band gap; furthermore, it is inexpensive and easy to process. However, the compatibility between PQDs and EVA should be established; therefore, a series of analyses was performed to compute parameters, such as the band gap, the coefficients of absorbance and extinction, the index of refractivity, and the dielectric constant (real and imaginary parts), from the data obtained from the above investigation. Finally, the optical conductivities of the films were studied. All these analyses showed that the EVA/PQDs were more efficient and stable both physically and optically. Hence, EVA/PQDs could become copolymer/perovskite active materials suitable for optoelectronic devices, such as solar cells and perovskite/polymer light-emitting diodes (PPLEDs).

scholarly journals Crystal‐size‐induced band gap tuning in perovskite films

2021 ◽  
Author(s):  
Amita Ummadisingu ◽  
Simone Meloni ◽  
Alessandro Mattoni ◽  
Wolfgang Tress ◽  
Michael Grätzel
Keyword(s):  
Band Gap ◽  
Crystal Size ◽  
Band Gap Tuning

scholarly journals Strain-tunable band alignment and band gap of GaSe/WTe2 heterojunction for water splitting and light-emitting

2021 ◽  
pp. 104605
Author(s):  
Qingyi Feng ◽  
Hongxiang Deng ◽  
Hongdong Yang ◽  
Shasha Ke ◽  
Haifeng Lv ◽  
...  
Keyword(s):  
Band Gap ◽  
Water Splitting ◽  
Band Alignment ◽  
Light Emitting
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