Development of a donor polymer using a B ← N unit for suitable LUMO/HOMO energy levels and improved photovoltaic performance

2015 ◽  
Vol 6 (46) ◽  
pp. 8029-8035 ◽  
Author(s):  
Zijian Zhang ◽  
Zicheng Ding ◽  
Chuandong Dou ◽  
Jun Liu ◽  
Lixiang Wang
Keyword(s):  
Energy Levels ◽  
Photovoltaic Performance ◽  
Homo Energy ◽  
Novel Approach

We report a novel approach to tune the LUMO/HOMO energy levels of polymer donors by replacing a C–C unit with a B ← N unit. The polymer containing a B ← N unit exhibits lower LUMO/HOMO levels and a narrower bandgap, leading to an improved photovoltaic performance.

scholarly journals Novel Approach to Tooth Chemistry: Quantification of Human Enamel Apatite in Context for New Biomaterials and Nanomaterials Development

2020 ◽  
Vol 22 (1) ◽  
pp. 279
Author(s):  
Andrzej Kuczumow ◽  
Renata Chałas ◽  
Jakub Nowak ◽  
Wojciech Smułek ◽  
Maciej Jarzębski
Keyword(s):  
Biomedical Applications ◽  
Energy Levels ◽  
New Class ◽  
Novel Approach ◽  
Human Enamel ◽  
Linear Profiles ◽  
Resistant Form ◽  
Molar Teeth ◽  
Stable Core ◽  
Nanoscale Level

A series of linear profiles of the elements of the enamel in human molar teeth were made with the use of an electron microprobe and a Raman microscope. It is postulated that the enamel can be treated as the superposition of variable “overbuilt” enamel on the stable “core” enamel at the macro-, micro- and nanoscale level. The excessive values characterize the “overbuilt enamel”. All the profiles of excessive parameters along the enamel thickness from the enamel surface to the dentin enamel junction (DEJ) can be approximated very precisely with the use of exponential functions, where Ca, P, Cl and F spatial profiles are decaying while Mg, Na, K and CO32− ones are growing distributions. The “overbuilt” apatite formed on the boundary with DEJ, enriched in Na, Mg, OH and carbonates, reacts continuously with Ca, Cl and F, passing into an acid-resistant form of the “overbuilt” enamel. The apparent phases arriving in boundary regions of the “overbuilt enamel” were proposed. Microdiffraction measurements reveal relative variation of energy levels during enamel transformations. Our investigations are the milestones for a further new class of biomaterial and nanomaterial development for biomedical applications.

A novel approach of an infrared transparent Er:Y2O3–MgO nanocomposite for eye-safe laser ceramics

2018 ◽  
Vol 6 (41) ◽  
pp. 11096-11103 ◽  
Author(s):  
Ho Jin Ma ◽  
Wook Ki Jung ◽  
Youngtae Park ◽  
Do Kyung Kim
Keyword(s):  
Photoluminescence Spectrum ◽  
Energy Levels ◽  
Laser Ceramics ◽  
Novel Approach

Photoluminescence spectrum and energy levels of an Er:Y2O3–MgO nanocomposite.

scholarly journals Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

2017 ◽  
Vol 13 ◽  
pp. 863-873 ◽  
Author(s):  
Vinila N Viswanathan ◽  
Arun D Rao ◽  
Upendra K Pandey ◽  
Arul Varman Kesavan ◽  
Praveen C Ramamurthy
Keyword(s):  
Molecular Orbital ◽  
Architectural Design ◽  
Density Functional ◽  
Short Circuit ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Hole Mobility ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Lowest Unoccupied Molecular Orbital

A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at −5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2, were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3.

scholarly journals Polymerized small molecular acceptor based all-polymer solar cells with an efficiency of 16.16% via tuning polymer blend morphology by molecular design

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaqi Du ◽  
Ke Hu ◽  
Jinyuan Zhang ◽  
Lei Meng ◽  
Jiling Yue ◽  
...  
Keyword(s):  
Solar Cells ◽  
Molecular Design ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Photovoltaic Performance ◽  
Electronic Energy ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Electronic Energy Levels ◽  
20 Nm

AbstractAll-polymer solar cells (all-PSCs) based on polymerized small molecular acceptors (PSMAs) have made significant progress recently. Here, we synthesize two A-DA’D-A small molecule acceptor based PSMAs of PS-Se with benzo[c][1,2,5]thiadiazole A’-core and PN-Se with benzotriazole A’-core, for the studies of the effect of molecular structure on the photovoltaic performance of the PSMAs. The two PSMAs possess broad absorption with PN-Se showing more red-shifted absorption than PS-Se and suitable electronic energy levels for the application as polymer acceptors in the all-PSCs with PBDB-T as polymer donor. Cryogenic transmission electron microscopy visualizes the aggregation behavior of the PBDB-T donor and the PSMA in their solutions. In addition, a bicontinuous-interpenetrating network in the PBDB-T:PN-Se blend film with aggregation size of 10~20 nm is clearly observed by the photoinduced force microscopy. The desirable morphology of the PBDB-T:PN-Se active layer leads its all-PSC showing higher power conversion efficiency of 16.16%.

Molecular engineering of the hole-transporting material spiro-OMeTAD via manipulation of alkyl groups

RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 60587-60594 ◽  
Author(s):  
D. Tomkute-Luksiene ◽  
M. Daskeviciene ◽  
T. Malinauskas ◽  
V. Jankauskas ◽  
R. Degutyte ◽  
...  
Keyword(s):  
Energy Levels ◽  
Substituent Effects ◽  
Molecular Engineering ◽  
Homo Energy ◽  
Molecular Glasses ◽  
Alkyl Groups ◽  
Hole Transporting ◽  
Aliphatic Substituent ◽  
Hole Transporting Material

Aliphatic substituent effects on the HOMO energy levels and the ability to transport charge and form stable molecular glasses of systematically modified spiro-OMeTAD analogues were investigated.

Detailed finer features in spectra of interfacial waves for characterization of a bubble-laden drop

2017 ◽  
Vol 831 ◽  
pp. 698-718 ◽  
Author(s):  
Udugama R. Sumanasekara ◽  
Sukalyan Bhattacharya
Keyword(s):  
Small Deviation ◽  
Energy Levels ◽  
Bond Number ◽  
Small Deviations ◽  
Quantum Numbers ◽  
Novel Approach ◽  
Arbitrary Location ◽  
The Individual ◽  
Concentric Geometry

This article describes unexplored details of the intriguing spectral manifestation of the small-amplitude waves at the surfaces of a bubble-laden drop. Its natural frequencies of interfacial pulsation reveal a non-trivial variation with the position of the cavity inside the liquid. This configurational dependence of spectra is calculated for arbitrary location of the void by using a novel approach under low capillary number and low Bond number limits. The analysis is based on expansion in two sets of basis functions where their mutual transformations are utilized to enforce interfacial boundary conditions. The obtained results quantify a few important features which have both scientific and technological significance. For a concentric geometry, the inherent azimuthal degeneracy makes the frequencies for a number of vibrational modes exactly the same. For an eccentric position of the bubble, however, this degeneracy disappears, creating small deviations in the spectral values corresponding to different azimuthal modes. Such behaviour is akin to fine-structure split in an atomic system, where different quantum numbers ensure small deviation in energy levels of the states. The formulated mathematical procedure can determine the individual frequency values for the interfacial oscillation even if these are grouped closely together in bands. The paper shows how the number of fine structures inside a band and their specific values can be exploited to predict the size and position of the cavity in an opaque drop without any direct visualization of its interior.

Fine-tuning HOMO energy levels between PM6 and PBDB-T polymer donors via ternary copolymerization

2020 ◽  
Vol 63 (9) ◽  
pp. 1256-1261 ◽  
Author(s):  
Xiaojun Li ◽  
Ruijie Ma ◽  
Tao Liu ◽  
Yiqun Xiao ◽  
Gaoda Chai ◽  
...  
Keyword(s):  
Energy Levels ◽  
Fine Tuning ◽  
Homo Energy
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