Dihydrophenazine-based double-anchoring dye for dye-sensitized solar cells

A novel dihydrophenazine-based organic di-anchoring dye DK-11 was synthesized by utilizing a simple synthetic protocol. The dye was characterized by optical and electrochemical studies and used as a sensitizer for dye-sensitized solar cell. The proposed butterfly structure was supported by IR experiments which ensured the binding of both carboxylic acid units on the semiconductor surface. Using the dye DK-11 , the device generated an efficiency of 5.07% with J_SC, V_OC, and FF values of 10.65 mA/cm², 0.67 V, and 0.71, respectively.     

Deuterated Epoxides and Their Polymers. I. Synthesis of cis- and trans-Propylene Oxide-1-d and Their NMR Spectra

Abstract

cis- and trans-Propylene oxide-1-d were synthesized from the corresponding propenyl halides via propenyllithium and propylene bromohydrin. Their NMR spectra (about 3% in benzene) were analyzed in terms of ABX₃ spin system and the assignment was carried out. The chemical shift of the methylene proton in cis position to the methyl group was found to be Δ = 1.86 ppm and that of the methylene proton in trans position Δ = 2.18 ppm (downfield from HMDS). The H-D couplings were observed in the methine-methylene part spectra decoupled from methyl protons. The observed J_HD's agree with the theoretical relation: J_HH = 6.5 14 X J_HD.     

Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation

To achieve high power conversion efficiency (PCE), three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent (J_sc) and photovoltage (V_oc). On basis of the XW4, a benzothiadiazole (BTD) unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability. As a result, a J_sc of 13.72 mA/cm² has been obtained for XW57, higher than that of XW4. On this basis, XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups, and the superior anti-aggregation character raises the V_oc from 781 mV (XW4) to 844 mV. When both the BTD unit and the bulky groups are introduced to the acceptor and donor units, respectively, the resulting sensitizer XW59 exhibits a highest PCE value of 7.34% with synergistically enhanced J_sc of 13.19 mA/cm² and V_oc of 793 mV. These results provide further insight into developing high performance dye-sensitized solar cells     

Luminescence characteristics and electronic levels of Eu(III) in the N,N-dimethyl-diphenyl-phosphinamide (DDPA) adduct of europium perrhenate

Optical absorption and emission spectra (1200-200 nm) of Eu(ReO₄)₃ · 2DDPA are measured between 77 and 650 K. Based on a C_s symmetry of the Eu(III) ion, a group theoretical analysis has been carried out and tentative assignments of ⁵D_J and ⁷F_J′ energy levels and their Stark splitting are made. The emission spectra measured with various Ar⁺ laser lines exhibit prominent fluorescence exclusively from ⁵D₀ to ⁷F_J′ levels. The relative intensities of the ⁵D_J emissions exhibit a temperature dependence showing a continuously decreasing intensity for the J ≥ 1 states. The ⁵D₀ state remains only a fluorescence state at higher temperatures (above ∼450 K). For J ≥ 1, the excited Eu(III) ions in these states decay by a combination of radiative transitions to the ⁷F_J′ levels and nonradiative processes operative within the ⁵D_J manifold.     

A NMR study of tetrathiofulvalene and tetracyanoquinodimethane: relative proton geometries and order parameters using nematic solvents; carbon-proton spin spin coupling constants for TTF

From proton magnetic resonance spectra of TTF and TCNQ partially oriented in nematic liquid crystal solvents the ratio of length to width of the proton rectangle is 3.124 ± 0.03 for TTF and 1.765 ± 0.024 for TCNQ. Values of J_CH obtained for TTF dissolved in d₆-acetone, are J_CH = 187.9 ± 0.3 Hz, J_CCH = 6.7 ±0.1 Hz and J_CSCH = 9.0 ±0.2 Hz.     

Structure and photoluminescence of Mg-Al-Eu ternary hydrotalcite-like layered double hydroxides

A series of Mg-Al-Eu ternary hydrotalcite-like layered double hydroxides (LDHs), with Eu/Al atomic ratios of ∼0.06 and Mg/(Al+Eu) atomic ratios ranging from 1.3 to 4.0, were synthesized by a coprecipitation method. The Mg-Al-Eu ternary LDHs were investigated by various techniques. X-ray diffraction (XRD) results indicated that the crystallinity of the ternary LDHs was gradually improved with the increase of Mg²⁺/(Al³⁺+Eu³⁺) molar ratio from 1.3/1 to 4/1, and all the samples were a single phase corresponding to LDH. The photoluminescent (PL) spectra of the ternary Mg-Al-Eu LDHs were described by the well-known ⁵D₀-⁷F_J transition (J=1, 2, 3, 4) of Eu³⁺ ions with the strongest emission for J=2, suggesting that the host LDH was favorable to the emissions of Eu³⁺ ions. The asymmetry parameter (R) relevant to ⁵D₀-⁷F_J transition (J=1, 2) dependant of the atomic ratios of Mg²⁺/(Al³⁺+Eu³⁺) was discussed, and was consistent with the result of XRD.     

19F nuclear magnetic resonance spectra of some trisubstituted metal trifluorophosphine complexes. Examples of [AX3]3 nuclear spin systems

The ¹⁹F NMR spectra of π-allyl-tris(trifluorophosphine)rhodium(I), [A], benzene-tris(trifluorophosphine)chromium(0), [B], and nitrosyl-tris(trifluorophosphine) rhodium(-I), [C], are presented. These are examples of [AX₃]₃ nuclear spin systems (A = phosphorus, X = fluorine). The spectra of [A] and [B] have been completely analysed to afford values of ¹J(PF), ²J(PP′), ³J(PF′) and ⁴J(FF′).     

A new study on solid-state cyanine dye-sensitized solar cells

A new cyanine dye, 7-{1-[2-(4-morpholine-1,8-naphthalimide)ethyl]-1H-1,2,3-triazol-4-}-2-[3-(5-carboxyl-1,3-dihydro-3,3-dimethyl-1-butyl-indolin-2-methylene)-propenyl]-1,1-dimethyl-3-buty-1H-benzo[e]indolium iodide (BIDC), has been synthesized and identified with regard to its structure and photoelectrochemical properties used as a sensitizer on dye-sensitized solar cells. A novel solid-state electrolyte with polyaniline-loaded carbon black (PACB)-1-methyl-3-propylimidazolium iodide (MPII) composite was investigated on these dye-sensitized solar cells (DSCs). The short-circuit photocurrent density (J _sc), open-circuit photovoltage (V _oc) and fill factor (ff) under 200 W/m² white light from a xenon lamp are 0.44 mA/cm², 550 mV and 0.58, respectively, yielding an overall conversion efficiency (η) of 0.7%. The most merit of the solid-sate electrolyte was free of volatile and flammable fluid components and easy of encapsulation for DSCs.     

Highly Efficient Dye‐Sensitized Solar Cells Based on Panchromatic Ruthenium Sensitizers with Quinolinylbipyridine Anchors

Panchromatic Ru^II sensitizers TF‐30–TF‐33 bearing a new class of 6‐quinolin‐8‐yl‐2,2′‐bipyridine anchor were synthesized and tested under AM1.5 G simulated solar irradiation. Their increased π conjugation relative to that of the traditional 2,2′:6′,2′′‐terpyridine‐based anchor led to a remarkable improvement in absorptivity across the whole UV–Vis–NIR spectral regime. Furthermore, the introduction of a bulky tert‐butyl substituent on the quinolinyl fragment not only led to an increase in the J_SC value owing to the suppression of dye aggregation, but remarkably also resulted in no loss in V_OC in comparison with the reference sensitizer containing a tricarboxyterpyridine anchor. The champion sensitizer in DSC devices was found to be TF‐32 with a performance of J_SC=19.2 mA cm^?2, V_OC=740 mV, FF=0.72, and η=10.19 %. This 6‐quinolin‐8‐yl‐2,2′‐bipyridine anchor thus serves as a prototype for the next generation of Ru^II sensitizers with any tridentate ancillary.     

Magnetic study of Cr ion in M2CrV3O11−x (MZn, Mg) compounds

Electron paramagnetic resonance (EPR) and magnetic susceptibility measurements on the recently synthesized vanadates M₂CrV₃O_11−x (M=Zn, Mg) have been analyzed. Two absorption lines with g≈2.0 (type I) and g≈1.98 (type II) were recorded in the EPR spectra, which can be attributed to V⁴⁺ ions and Cr³⁺ ion clusters (pairs), respectively. The exchange constant J between Cr³⁺ ions has been calculated, using both EPR and magnetic susceptibility data. Fitting of the EPR and magnetic susceptibility data has been carried out. The sign of J is a negative one for all samples and indicates antiferromagnetic interactions. Some difference in the J constant value among samples has been obtained. Volumetric titration confirms distinctly the presence of vanadium V⁴⁺ ions in the investigated compounds.     

A high-efficiency cyanine dye for dye-sensitized solar cells

A novel organic cyanine dye containing triphenylamine-benzothiadiazole dyad has been synthesized and applied successfully to sensitization of nanocrystalline TiO₂-based solar cell. Their absorption spectra, electrochemical, and photovoltaic properties were studied. Upon adsorption on a TiO₂ electrode, the absorption spectra of the cyanine dye are all broadened at both the red and blue spectral ends relative to its respective spectra in acetonitrile and ethanol mixture solution. An overall conversion efficiency of 7.62% (J_sc=22.10 mA cm⁻², V_oc=0.54 V, ff=0.48) is achieved under irradiation with 75 mW cm⁻² white light from a Xe lamp.     

Measurement of deuterium quadrupole coupling in CH3OD

K = 1 → 0 transitions in CH₃OD for J = 1, 2, 3 and 4 E₂-type states were measured using a beam maser spectrometer with 6 kHz linewidth (fwhm). Analysis of J = 1 and J = 2 spectra provided a deuterium quadrupole coupling strength along the O-D bond dijection of eg_zzQ = 303 ± 12 kHz.     

Chemo-and stereoselectivity of the reaction of aromatic aldehydes with triphenylphosphine and trichloroacetic acid derivatives

Aromatic aldehydes react with triphenylphosphine and ethyl trichloroacetate or trichloroacetonitrile to give the corresponding benzylidene dichlorides or α-chlorocinnamic acid derivatives. The chemo-and regioselectivity of these reactions depend on both the substituent in the aromatic ring and reaction conditions. The product configuration was determined on the basis of the coupling constants ² J _CH and ³ J _CH in the ¹³C NMR spectra.     

29Si and 13C NMR Studies of organofunctional di- and trisilanes

A series of di- and trisilanes of general structure Ph₃SiSiMe₂R and (Ph₃Si)₂SiR′R″ were synthesized, and the ²⁹Si and ¹³C chemical shifts and one-bond siliconsilicon coupling constants (¹J_SiSi) were measured. The coupling constants of the disilanes were found to be primarily dependent upon the inductive effect of the alkyl group, R, as measured by the Taft o^★ constant. In both series of compounds, increasing alkyl substitution at silicon led to a decrease in ¹J_SiSi.     

Comparison of 7FJ←5DO emission spectra for Eu(III) in crystalline environments of octahedral,near-octahedral,and trigonal symmetry

Isotropic ⁷F_J←⁵D_O emission spectra are reported for Eu(III) in four different crystalline system. These systems differ with respect to Eu(III) site symmetry, coordination number, coordination geometry, and the chemical nature of the coordinated ligands. Comparison between the spectra obtained on these systems reveal major differences in the relative intensities of the ⁷F_J←⁵D_O emission, and these differences are discussed in terms of ligand modulated 4f — 4f intensity mechanism.     

The effect of the nitrogen non-bonding electron pair on the NMR and X-ray in 1,3-diazaheterocycles

The effect of the nitrogen nonbonding electron pair on the ¹J_C,H values of 1,3-diazaheterocycles was analyzed and compared to 1,5-diazabiciclo[3.2.1]octanes, which have a restricted conformation. The ¹J_C,H values were measured by observing the ¹³C satellites in the ¹H NMR spectra and then determining the ¹H-coupled ¹³C NMR spectra. The ¹J_C,H values are 10 Hz larger when the α-hydrogen is synperiplanar rather than antiperiplanar to the nonbonding electron pair on the nitrogen, which serves as experimental evidence of the orbital n_N→σ¹_C,Hap interactions. In addition, the homoanomeric effect from the interactions of the nitrogen lone pair with the antibonding orbital of the equatorial hydrogen, which was in the β position, was discussed (n_N→σ¹_C(β),Heq).     

Novel organic sensitizers containing a bulky spirobifluorene unit for solar cell

Three organic sensitizers JK-87, JK-88, and JK-89 containing a bulky spirobifluorene unit in the bridged group are designed and synthesized. Under standard global A.M. 1.5 solar condition, the JK-89 sensitized cell gave a short-circuit photocurrent density (J_sc) of 13.02 mA cm⁻², an open-circuit voltage (V_oc) of 0.75 V, and a fill factor of 0.70, corresponding to an overall conversion efficiency η of 6.83%. The η of JK-89 is higher than those of other two cells due to the larger J_sc. The improved J_sc value is mainly attributed to the broad and red-shifted absorption band.     

NMR study (1H, 13C and 29Si) of (CH3)4−x Si(CHCH2)x compounds where x = 0, 1, 2, 3, 4

The ¹H, ¹³C and ²⁹Si NMR spectra of the various methylvinylsilanes have been analysed with the aid of a special simulation program. From considerations of the chemical shifts and of the coupling constants ^2,3j_¹H-¹H, ¹J_¹³C-¹H, ¹J_{²⁹Si-¹³C} and ²J_{²⁹Si-C-¹H} it is shown that a mesomeric —M effect from the vinyl group to the Me—Si group is important, in very good agreement with previously published PES results [1–3]. The mesomeric interaction in this series is ascribed to a {d, σ^*—π} hyperconjugation in accordance with theoretical considerations [4].     

Temperature dependence of broadening and shifts of methane lines in the ν4 band

We have recorded high-resolution absorption spectra of methane broadened by dry air and by N₂ at temperatures from −63 to 41°C using a Fourier transform spectrometer. These spectra have been analyzed to determine pressure broadening and line-shift coefficients, along with their temperature dependences, for 148 lines in the ν₄ fundamental band of ¹²CH₄. The experimental uncertainties for lines with J″≤10 are generally <2% for the broadening coefficient b⁰_L, 6–12% for its temperature dependence exponent n, 6–20% for the line-shift coefficient δ⁰, and 20–40% for its temperature dependence coefficient δ′; for J″> 10 the experimental uncertainties are somewhat larger. These results, especially for N₂-broadening, are in excellent agreement with other recent measurements. Since the present results cover a wide range of rotational quantum numbers (J″ up to 14), the variation of the temperature dependence of the half-widths and shifts from line to line within the ν₄ band is also examined.     

Influence of effective two- and three-particle interactions on atomic fine structure in mixed configurations (5d+6s) N

The influence of all effective two- and three-particle interactions appearing in second order of perturbation theory was investigated for the 5d-shell atoms Hf, Ta, W, Re, and Os. The radial parts of the effective operators were treated as free parameters which were determined by a least squares fit of calculated energy levels to the observed ones. An appreciable reduction of the mean deviation was achieved in all spectra considered. A test of the eigenvectors of the effective Hamiltonian was performed by a comparison of calculatedg _J values andg _J values, which were measured with high precision by radiofrequency spectroscopy. The agreement found is typically better than a few parts in 10⁴.