Charge self-compensated doped polymers (Conference Presentation)

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

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Developing Eco-Friendly and Cost-Effective Porous Adsorbent for Carbon Dioxide Capture

Molecules ◽

10.3390/molecules26071962 ◽

2021 ◽

Vol 26 (7) ◽

pp. 1962

Author(s):

Mahboubeh Nabavinia ◽

Baishali Kanjilal ◽

Noahiro Fujinuma ◽

Amos Mugweru ◽

Iman Noshadi

Keyword(s):

Carbon Dioxide ◽

Surface Area ◽

Co2 Capture ◽

High Surface ◽

Scale Up ◽

Polymer Networks ◽

High Surface Area ◽

Excellent Thermal Stability ◽

Doped Polymers ◽

Metal Doped

To address the issue of global warming and climate change issues, recent research efforts have highlighted opportunities for capturing and electrochemically converting carbon dioxide (CO2). Despite metal doped polymers receiving widespread attention in this respect, the structures hitherto reported lack in ease of synthesis with scale up feasibility. In this study, a series of mesoporous metal-doped polymers (MRFs) with tunable metal functionality and hierarchical porosity were successfully synthesized using a one-step copolymerization of resorcinol and formaldehyde with Polyethyleneimine (PEI) under solvothermal conditions. The effect of PEI and metal doping concentrations were observed on physical properties and adsorption results. The results confirmed the role of PEI on the mesoporosity of the polymer networks and high surface area in addition to enhanced CO2 capture capacity. The resulting Cobalt doped material shows excellent thermal stability and promising CO2 capture performance, with equilibrium adsorption of 2.3 mmol CO2/g at 0 °C and 1 bar for at a surface area 675.62 m2/g. This mesoporous polymer, with its ease of synthesis is a promising candidate for promising for CO2 capture and possible subsequent electrochemical conversion.

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n-type charge transport in heavily p-doped polymers

Nature Materials ◽

10.1038/s41563-020-00859-3 ◽

2021 ◽

Author(s):

Zhiming Liang ◽

Hyun Ho Choi ◽

Xuyi Luo ◽

Tuo Liu ◽

Ashkan Abtahi ◽

...

Keyword(s):

Charge Transport ◽

Doped Polymers

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Overcoming the water oxidative limit for ultra-high-workfunction hole-doped polymers

Nature Communications ◽

10.1038/s41467-021-23347-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Qi-Mian Koh ◽

Cindy Guanyu Tang ◽

Mervin Chun-Yi Ang ◽

Kim-Kian Choo ◽

Qiu-Jing Seah ◽

...

Keyword(s):

Organic Semiconductors ◽

Water Oxidation ◽

Soft Materials ◽

Bulk Water ◽

Oxidation Potential ◽

Doped Semiconductors ◽

Good Thermal Stability ◽

Doped Polymers ◽

Super Acid ◽

Maximum Work

AbstractIt is widely thought that the water-oxidation reaction limits the maximum work function to about 5.25 eV for hole-doped semiconductors exposed to the ambient, constrained by the oxidation potential of air-saturated water. Here, we show that polymer organic semiconductors, when hole-doped, can show work functions up to 5.9 eV, and yet remain stable in the ambient. We further show that de-doping of the polymer is not determined by the oxidation of bulk water, as previously thought, due to its general absence, but by the counter-balancing anion and its ubiquitously hydrated complexes. The effective donor levels of these species, representing the edge of the ‘chemical’ density of states, can be depressed to about 6.0 eV below vacuum level. This can be achieved by raising the oxidation potential for hydronium generation, using large super-acid anions that are themselves also stable against oxidation. In this way, we demonstrate that poly(fluorene-alt-triarylamine) derivatives with tethered perfluoroalkyl-sulfonylimidosulfonyl anions can provide ambient solution-processability directly in the ultrahigh-workfunction hole-doped state to give films with good thermal stability. These results lay the path for design of soft materials for battery, bio-electronic and thermoelectric applications.

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Quadratic electroabsorption spectroscopy as a probe of χ(3)mechanisms in dye-doped polymers

10.1117/12.165273 ◽

1993 ◽

Author(s):

Constantina Poga ◽

Mark G. Kuzyk ◽

Sergio Martinez ◽

Carl W. Dirk

Keyword(s):

Doped Polymers ◽

Electroabsorption Spectroscopy

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Volume phase gratings in DMPA-doped polymers

Applied Physics A Solids and Surface ◽

10.1007/bf00323617 ◽

1994 ◽

Vol 58 (4) ◽

pp. 401-405 ◽

Cited By ~ 3

Author(s):

P. Dre� ◽

T. Kardinahl ◽

H. Franke

Keyword(s):

Volume Phase ◽

Doped Polymers

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Photoconductivity of Low-Bandgap Polymer and Polymer: Fullerene Bulk Heterojunction Studied by Constant Photocurrent Method

Organic Photonics and Photovoltaics ◽

10.1515/oph-2015-0011 ◽

2015 ◽

Vol 3 (1) ◽

Cited By ~ 2

Author(s):

V. V. Malov ◽

A. R. Tameev ◽

S. V. Novikov ◽

M. V. Khenkin ◽

A. G. Kazanskii ◽

...

Keyword(s):

Molecular Orbital ◽

Bulk Heterojunction ◽

Inorganic Materials ◽

Fullerene Derivative ◽

Approximation Procedure ◽

Photoelectric Properties ◽

Highest Occupied Molecular Orbital ◽

Donor Acceptor ◽

Lowest Unoccupied Molecular Orbital ◽

Doped Polymers

AbstractOptical and photoelectric properties of modern photosensitive polymers are of great interest due to their prospects for photovoltaic applications. In particular, an investigation of absorption and photoconductivity edge of these materials could provide valuable information. For these purpose we applied the constant photocurrent method which has proved its efficiency for inorganic materials. PCDTBT and PTB7 polymers were used as objects for the study as well as their blends with a fullerene derivative PC71BM. The measurements by constant photocurrent method (CPM) show that formation of bulk heterojunction (BHJ) in the blends increases photoconductivity and results in a redshift of the photocurrent edge in the doped polymers compared with that in the neat polymers. Obtained from CPM data, spectral dependences of absorption coefficient were approximated using Gaussian distribution of density-of-states within HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) bands. The approximation procedure allowed us to evaluate rather optical than electrical bandgaps for the studied materials. Moreover, spectra of polymer:PC71BM blends were fitted well by the sum of two Gaussian peaks which reveal both the transitions within the polymer and the transitions involving charge transfer states at the donor-acceptor interface in the BHJ.

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