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Design, Synthesis and Application of Imidazole-Based Organic Dyes in Dye Sensitized Solar Cells
摘要： Metal-free D–D–p–A type dyes (i.e., Car-Cy, Car-Rh, Dpa-Cy, and Dpa-Rh) were designed and synthesized for dye-sensitized solar cells (DSSCs). In the structure of the sensitized dyes, an imidazole ring is connected to a carbazole or diphenylamine moiety as a donor while cyanoacetic acid or rhodanine-3-acetic acid was introduced as an acceptor/anchor. The molecular structures of D–D–p–A type dyes were characterized using IR, NMR and MS spectral data. The optical, electrochemical, theoretical, light harvesting property, HOMO/LUMO levels, redox behavior, and photovoltaic properties of the synthesized dyes were evaluated. Among the fabricated photovoltaic devices based on the prepared dye, Dpa-Cy dye containing diphenylamine as a donor and cyanoacetic acid as an acceptor exhibited a high-power conversion efficiency of 1.70% with a short-circuit current density (JSC) of 4.48 mA cm?2, an open-circuit photovoltage (VOC) of 0.53 V and a fill factor of 72% under AM1.5 illumination (85 mW cm?2) in comparison with other dyes. Plane-wave calculations indicate that the dye binds reasonably strongly to the TiO2 surface, and the generated DOS picture shows an overlap of the molecular orbitals of the dye and the TiO2 bands. We conclude that the dyes have a promising role as sensitizers in DSSCs.
关键词： rhodanine-3-acetic acid,cyanoacetic acid,carbazole,DSSCs,diphenylamine
更新于2025-09-23 15:21:01
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Diphenylamine/triazine hybrids as bipolar hosts for phosphorescent organic light-emitting diodes
摘要： The bipolar host materials employing diphenylamine (DPA) as donor unit and triazine (TRZ) as acceptor unit could achieve suitable energy levels and balanced charge transporting properties, which are necessary for high performance of organic light-emitting diodes (OLEDs). In this work, three DPA/TRZ based host materials, named 2-(4-(N,N-diphenylamino)phenyl)-4,6-diphenyl-1,3,5-triazine (DPA-TRZ), 2,4-bis(4-(N,N-diphenylamino)phenyl)-6-phenyl-1,3,5-triazine (DDPA-TRZ), and 2,4,6-tris(4-(N,N-diphenylamino)phenyl)-1,3,5-triazine (TDPA-TRZ) were designed and synthesized. Their thermal, photophysical, electrochemical, and carrier transporting properties were investigated to reveal the relationship between molecular structure and properties. The number of DPA units could regularly tune the optical and electrical properties of the hybrids. The triplet excited state energy (ET) values of DPA-TRZ, DDPA-TRZ, and TDPA-TRZ are 2.38, 2.51, and 2.73 eV, respectively. To evaluate the electroluminescent properties of the three host materials, blue, green, red, and white phosphorescent OLEDs (PhOLEDs) were fabricated and characterized. With the highest ET value, TDPA-TRZ can afford from blue to red phosphorescent emitters. All these devices exhibited EQEs of over 20% with relatively low efficiency roll-offs. The single-host white PhOLEDs based on TDPA-TRZ showed impressive color stability and superior color rendition. These results demonstrate that the combination of DPA and TRZ is an effective way to construct highly efficient bipolar host materials.
关键词： diphenylamine,triazine,phosphorescent organic light-emitting diodes,charge transporting properties,bipolar host materials
更新于2025-09-23 15:19:57
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Solution-Processible Blue Fluorescent Dendrimers with Carbazole/Diphenylamine Hybrid Dendrons for Power-Efficient Organic Light-Emitting Diodes
摘要： Two blue ?uorescent dendrimers named PVAC2 and PVACA have been newly synthesized and investigated, where the carbazole/diphenylamine hybrid dendron is adopted instead of oligocarbazole. Compared with the reference dendrimer PVCt3, the emission maxima of PVAC2 and PVACA are found to be red-shifted accompanied by a slight reduction of the photoluminescence quantum yield in ?lms. Most importantly, the highest occupied molecular orbital level is elevated from ?5.35 eV of PVCt3 to ?5.20 eV of PVAC2 and ?4.95 eV of PVACA. Because of the favored hole injection, the turn-on voltage is accordingly decreased from 3.6 to 3.2 and 2.6 V. The value of PVACA is even lower than the theoretical limit of 2.78 V. In addition, PVAC2 exhibited the best nondoped device performance, showing a nearly doubled power e?ciency of 4.80 lm/W relative to PVCt3 (2.37 lm/W). The results clearly indicate that dendron engineering is also a promising strategy to develop solution-processible blue ?uorescent dendrimers capable of being used for power-e?cient organic light-emitting diodes.
关键词： solution-processible,blue fluorescent dendrimers,power-efficient organic light-emitting diodes,carbazole/diphenylamine hybrid dendron
更新于2025-09-12 10:27:22
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The LH2 Complexes (B800-850 and B800-830) Are Assembled in the Cells of the Sulfur Bacterium Thiorhodospira sibirica Strain Kir-3 without Carotenoids
摘要： The results of assembling the light-harvesting complexes in the cells of the purple sulfur bacterium Thiorhodospira (T.) sibirica strain Kir-3 while suppressing the biosynthesis of carotenoids with diphenylamine (DPA) were studied. LH2 complexes (B800-850 and B800-830) with different carotenoid composition were isolated from the cells obtained. Maximum inhibition of carotenoid biosynthesis (~90% of the control) was reached at an inhibitor concentration of 53.25 μ M (9 mg/L). It was established that changes in the qualitative and quantitative composition of carotenoids do not affect the assembly of B800-830 and B800-850 complexes. It is assumed that, in the population of DPA-LH2 complexes from T. sibirica strain Kir-3, both the carotenoidless complexes and the complexes containing one or two carotenoid molecules can be assembled. These results support the hypothesis that carotenoids are not required for assembling B800-850 and B800-830 complexes.
关键词： Thiorhodospira sibirica,diphenylamine,B800-850,carotenoids,B800-830,LH2 complexes
更新于2025-09-11 14:15:04
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SYNTHESIS, CHARACTERIZATION OF A NOVEL CONJUGATED STRUCTURAL OLIGOMER
摘要： An octupolar star-shaped ladder–type oligomer composed of electron deriving from 1,3,5-triazine core end-capped by either an electron donating carbazolemoiety(TA(TL)-Ph(3)-CBZ) have been designed and synthesized to investigate the structure-properties relationship of highly efficient multiphoton absorbing materials. The newly synthesized molecules were characterized by 1H NMR, 13C NMR and mass spectrometry. Linear optical properties of the oligomer were investigated by UV-vis and fluorescence spectrometries, as well as the nonlinear optical properties were characterized by two-photon excited fluorescence (2PEF) measurement.
关键词： TA(TL)-Ph (3)-CBZ,Oligomer,ter(p-phenylene),diphenylamine,MPA
更新于2025-09-09 09:28:46