Wireless Information Transmission System Powered by an Abiotic Biofuel Cell Implanted in an Orange

An “abiotic” biofuel cell composed of catalytic electrodes modified with inorganic nanoparticles (NPs) deposited on carbon black (CB) was used to activate a wireless information transmission system. The cathode and anode were made of carbon paper modified with Pt‐NPs/CB and buckypaper modified with Au₈₀Pt₂₀‐NPs/CB, respectively. The cathode/anode pair was implanted in orange pulp extracting power from its content (glucose and fructose in the juice). The open circuit voltage, V_oc, short circuit current density, j_sc, and maximum power produced by the biofuel cell, P_max, were found as 0.36 V, 1.3 mA cm^?2 and 182 µW, respectively. The voltage produced by the biofuel cell was amplified with an energy harvesting circuit and applied to a wireless transmitter. The present study continues the research line where different implantable biofuel cells are used for activation of electronic devices.     

Molecular Engineering of Simple Phenothiazine‐Based Dyes To Modulate Dye Aggregation,Charge Recombination,and Dye Regeneration in Highly Efficient Dye‐Sensitized Solar Cells

A series of simple phenothiazine‐based dyes, namely, TP , EP , TTP , ETP , and EEP have been developed, in which the thiophene (T), ethylenedioxythiophene (E), their dimers, and mixtures are present to modulate dye aggregation, charge recombination, and dye regeneration for highly efficient dye‐sensitized solar cell (DSSC) applications. Devices sensitized by the dyes TP and TTP display high power conversion efficiencies (PCEs) of 8.07 (J_sc=15.2 mA cm^?2, V_oc=0.783 V, fill factor (FF)=0.679) and 7.87 % (J_sc=16.1 mA cm^?2, V_oc=0.717 V, FF=0.681), respectively; these were measured under simulated AM 1.5 sunlight in conjunction with the I^?/I₃^? redox couple. By replacing the T group with the E unit, EP ‐based DSSCs had a slightly lower PCE of 7.98 % with a higher short‐circuit photocurrent (J_sc) of 16.7 mA cm^?2. The dye ETP , with a mixture of E and T, had an even lower PCE of 5.62 %. Specifically, the cell based on the dye EEP , with a dimer of E, had inferior J_sc and V_oc values and corresponded to the lowest PCE of 2.24 %. The results indicate that the photovoltaic performance can be finely modulated through structural engineering of the dyes. The selection of T analogues as donors can not only modulate light absorption and energy levels, but also have an impact on dye aggregation and interfacial charge recombination of electrons at the interface of titania, electrolytes, and/or oxidized dye molecules; this was demonstrated through DFT calculations, electrochemical impedance analysis, and transient photovoltage studies.     

p-DSSCs with BiOCl and BiOBr semiconductor and polybromide electrolyte

BiOCl and BiOBr nanodiscs (100–150 nm in diameter, 15–25 nm in thickness) are prepared via water-based nucleation and purified by a phase-transfer reaction, including oleylamine-induced transfer of the as-prepared nanodiscs from the polar water phase to the non-polar toluene phase. The oleylamine-capping is then removed by hydrazine treatment, and the BiOCl/BiOBr nanodiscs are redispersed in 2-propanol. The as-prepared nanodiscs are finally deposited as a porous, p-type semiconductor layer to obtain dye-sensitized solar cells (DSSCs). Herein, coumarin 343 is applied as sensitizer together with BiOCl as p-type semiconductor and a KI–I₂ electrolyte. In addition, eosin Y is applied as sensitizer together with BiOBr as p-type semiconductor and a [C₄MPyr]₂[Br₂₀] polybromide electrolyte (C₄MPyr: N-butyl-N-methylpyrrolidinium). Such polybromide electrolyte is firstly applied in a DSSC and allows for a higher redox potential. Both here established p-DSSCs show the characteristic features and function of a solar cell (BiOCl/coumarin 343/KI–I₂: V_oc = 120 mV, J_sc = 57 μA cm⁻², FF = 40.6%, η = 0.003; BiOBr/eosin Y/[C₄MPyr]₂[Br₂₀]: V_oc = 78 mV, J_sc = 3.1 μA cm⁻², FF = 28.6%, η = 0.0005) as a result of this conceptual study.     

Rotating-disc electrode studies of the anodic oxidation of iodide in concentrated iodine + iodide solutions

The anodic oxidation of iodide on platinum in concentrated iodine + iodide solutions has been investigated using a rotating disc electrode. The conventional limiting diffusion current, which is produced by the diffusion of iodide ions towards the electrode, was not observed due to the formation of an iodine film on the electrode. On the other hand, the steady-state anodic current after a current/time transient is the genuine limiting diffusion current in the anodic oxidation due to diffusion of iodine species from the electrode surface towards the bulk solution. Thus, the dissolution-diffusion control mechanism of the iodine film is confirmed. This is interesting as a typical example of an anodic process in a redox system governed by diffusion of the anodic product species from the electrode surface towards the bulk solution. When an iodine film is formed on the electrode, the maximum driving force of the iodine species is Δm_I2,max, which is defined as the extent of unsaturation of the iodine, and the limiting current of the anodic oxidation of iodide is always directly proportional to Δm_I2,max, regardless of the forms of iodine species in the solution, which may be I₂, I⁻₃, i₅⁻, etc. δm_I2,max is clearly determined by the solution composition and temperature, and it is different in definition and value from the usual degree of unsaturation of iodine.     

Structural and optical properties of tripod-like ZnO thin film and its application in dye-sensitized solar cell

In this work, we have synthesized Zinc oxide (ZnO) tripods and used its thin film as photoanode in dye-sensitized solar cells. SEM micrographs of the as-prepared sample of ZnO confirmed tripod-like morphology consisting of three cylindrical arms with well-defined ends, joined at a common core. The prepared sample of ZnO tripods was further characterized by EDX, XRD, UV-VIS, and FTIR. The dye N719-sensitized solar cell fabricated with photoanode of ZnO prepared in this work provided the open-circuit photo voltage (V _oc)?=?0.558 V, short-circuit photocurrent (J _sc)?=?6.368 mA?cm^-2, fill factor (FF)?=?0.50, and total conversion efficiency (η)?=?0.88 % under full light illumination (intensity 200 mW?cm^?2). When cell was illuminated by visible light (150 mW/cm²), V _oc?=?0.546 V, J _sc?=?4.437 mA/cm², FF?=?0.54, and η?=?0.88 % were obtained.     

Novel organic dyes containing bis-dimethylfluorenyl amino benzo[b]thiophene for highly efficient dye-sensitized solar cell

Novel organic dyes, JK-16 and JK-17 containing bis-dimethylfluorenyl amino benzo[b]thiophene are designed and synthesized. Under standard global AM 1.5 solar condition, the JK-16 sensitized cell gave a short circuit photocurrent density (J_sc) of 15.33 mA cm⁻², open circuit voltage (V_oc) of 0.74 V, and a fill factor of 0.66, corresponding to an overall conversion efficiency η of 7.43%, and the JK-17 sensitized cell gave a J_sc of 12.66 mA cm⁻², V_oc of 0.67 V, and a fill factor of 0.65, corresponding to an overall conversion efficiency η of 5.49%.     

Anthracene based organic dipolar compounds for sensitized solar cells

Organic dyes that consist of an anthracene moiety between a triphenylamine donor group and a cyanoacrylic acid acceptor group displayed remarkable solar-to-energy conversion efficiency in dye-sensitized solar cells. The planar geometry of anthracene and its bulky substituents helped the dyes to form a high quality monolayer on the surface of TiO₂. A typical device made with the dye AN-Bu displayed a maximal photon-to-current conversion efficiency (IPCE) 65% in the region of 350–510 nm, a short-circuit photocurrent density (J_sc) 12.78 mA cm⁻², an open-circuit photovoltage (V_oc) 0.73 V, and a fill factor (FF) 0.67, corresponding to an overall conversion efficiency 6.23%. In an experiment of using deoxycholic acid (DCA) as a co-absorbent, the values of V_oc stayed in a similar range, yet the values of J_sc were reduced in ca. 11% due to a decrease of loading amounts. This result indicated that the quality of the dye films cannot be further improved by the adding of DCA. The photophysical properties were analyzed with the aid of a time-dependent density functional theory (TDDFT) model with the B3LYP functional.     

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     

Organic dyes with a novel anchoring group for dye-sensitized solar cell applications

Two novel trialkylsilyl-containing organic sensitizers (JK-53 and JK-54) have been designed and synthesized. Nanocrystalline TiO₂–silica-based dye-sensitized solar cells (DSSCs) were fabricated using these dyes. Under standard global AM 1.5 solar conditions, the JK-53-sensitized cell gave a short-circuit photocurrent density (J_sc) of 6.37 mA cm^?2, an open-circuit voltage (V_oc) of 0.70 V, and a fill factor of 0.74. These values correspond to an overall conversion efficiency (η) of 3.31%. By comparison, the JK-54-sensitized cell resulted in a J_sc of 7.52 mA cm^?2, a V_oc of 0.71 V, and a fill factor of 0.75. These values give an overall conversion efficiency of 4.01%.     

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.     

Photovoltaic properties of new cyanine-naphthalimide dyads synthesized by ‘Click’ chemistry

Two novel cyanine dyads, in which a naphthalimide unit is attached to benzoindole ring of unsymmetric trimethine cyanine, have been synthesized via ‘Click’ reaction and characterized by ¹H NMR, ¹³C NMR, and MS-ESI. Under the illumination of AM 1.5 (75 mW cm⁻²), the power conversion efficiency of cyanine I reached 4.8% (J_sc = 14.5 mA cm⁻², V_oc = 0.50, FF = 0.49). The results show that the two cyanine dyes are promising sensitizers for nanocrystalline dye-sensitized solar cell.     

Photovoltaic characteristics of dye-sensitized surface-modified nanocrystalline SnO2 solar cells

Zinc-modified nanocrystalline SnO₂ electrodes are prepared by chemical treatment of the commercial SnO₂ colloid with zinc acetate and their thickness effects on photovoltaic characteristics are investigated. Open-circuit voltage (V_oc) and fill factor increase with increasing zinc concentration, while short-circuit photocurrent (J_sc) decreases. The normalized incident photon-to-current conversion efficiency (IPCE) shows that increase of zinc concentration utilizes long wavelength light. Concerning the conversion efficiency, optimal concentration within the present experiment is found to be 10 mol.% Zn²⁺ with respect to Sn⁴⁺. As increasing thickness of the films based on 10 mol.% zinc-modified SnO₂ ranging from 0.76 to 8.12 μm, J_sc increases, reaches maximum and then decreases without change in V_oc. The highest conversion efficiency of about 3.4% is achieved under 1 sun of AM 1.5 irradiation for the ∼6.3 μm-thick 10 mol.% zinc-modified SnO₂ film with J_sc of 9.09 mA/cm², V_oc 600 mV and fill factor 62%.     

Photoelectrochemical behavior of coupled SnO2|CdSe nanocrystalline semiconductor films

A photoelectrochemical cell with a coupled SnO₂|CdSe nanocrystalline semiconductor electrode has been prepared by sequential deposition of SnO₂ and CdSe films onto an optically transparent electrode (OTE), and its photoelectrochemical behavior has been studied. The results show that the coupling of CdSe with SnO₂ leads to an improvement in the performance of OTE|SnO₂|CdSe over OTE|CdSe cells in terms of increased incident photon-to-current conversion efficiency, increased stability and smaller reversal of current. The favorable positioning of the energy bands of SnO₂ and CdSe is responsible for the above observations. Various photoelectrochemical parameters of the OTE|SnO₂|CdSe cell obtained for an incident light power of 0.31 mW cm⁻² at 470nm, are as follows: I_sc ≈ 25–30 μA cm⁻², V_oc ≈ 0.5–0.6 V, ƒƒ = 0.47 and a power conversion efficiency of about 2.25%.     

Effect of TiO2 nanostructure morphology on the performance of a photoelectrochemical cell of ITO/TiO2/electrolyte/platinum

The morphology of photovoltaic material is able to influence of the performance of photoelectrochemical cell. Polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), and hexamethylenetetramine (HMT) surfactant were used to modify the morphology nanostructure of TiO₂ films by a simple technique, namely, liquid phase deposition during their growth process. It was found that the untreated surfactant TiO₂ film produces the morphology with the mixture nanosphere and nanoflower. The film treated with PVP, CTAB, and HMT produce the nanostructure shape of nanoflower, nanowire, and nanorod, respectively. These TiO₂ samples were utilized as photovoltaic materials in a photoelectrochemical cell of ITO/TiO₂/electrolyte/platinum. It was found that the photovoltaic parameters such as short-circuit current density (J _sc), open-circuit voltage (V _oc) and fill factor are influenced by the morphology in terms of shape and particle size of the TiO₂ nanostructure. The cell utilizing the TiO₂ nanowire treated with PVP possesses the highest J _sc and V _oc of 0.100 mAcm^?2 and 0.44 V. The length of the TiO₂ nanowire is 6?±?2 nm, while the cell with the untreated surfactant TiO₂ sample demonstrates the lowest performance. It was also found that the J _sc and V _oc increase with the decrease in the length of the TiO₂ nanostructures. The smallest length of TiO₂ possesses the best interfacial contact at TiO₂/electrolyte containing iodide/triiodide redox couple. Thus, the redox reaction is optimized at this interface.     

Anthracene‐Containing Wide‐Band‐Gap Conjugated Polymers for High‐Open‐Circuit‐Voltage Polymer Solar Cells

The synthesis, characterization, and photophysical and photovoltaic properties of two anthracene‐containing wide‐band‐gap donor and acceptor (D–A) alternating conjugated polymers ( P1 and P2 ) are described. These two polymers absorb in the range of 300–600 nm with a band gap of about 2.12 eV. Polymer solar cells with P1 :PC₇₁BM as the active layer demonstrate a power conversion efficiency (PCE) of 2.23% with a high V_oc of 0.96 V, a J_sc of 4.4 mA cm⁻², and a comparable fill factor (FF) of 0.53 under simulated solar illumination of AM 1.5 G (100 mW cm⁻²). In addition, P2 :PC₇₁BM blend‐based solar cells exhibit a PCE of 1.42% with a comparable V_oc of 0.89 V, a J_sc of 3.0 mA cm⁻², and an FF of 0.53.

     

Cyclometalated Ruthenium(II) Complexes Featuring Tridentate Click‐Derived Ligands for Dye‐Sensitized Solar Cell Applications

A series of heteroleptic bis(tridentate) Ru^II complexes featuring N^C^N‐cyclometalating ligands is presented. The 1,2,3‐triazole‐containing tridentate ligands are readily functionalized with hydrophobic side chains by means of click chemistry and the corresponding cyclometalated Ru^II complexes are easily synthesized. The performance of these thiocyanate‐free complexes in a dye‐sensitized solar cell was tested and a power conversion efficiency (PCE) of up to 4.0 % (J_sc=8.1 mA cm^?2, V_oc=0.66 V, FF=0.70) was achieved, while the black dye ((NBu₄)₃[Ru(Htctpy)(NCS)₃]; Htctpy=2,2′:6′,2′′‐terpyridine‐4′‐carboxylic acid‐4,4′′‐dicarboxylate) showed 5.2 % (J_sc=10.7 mA cm^?2, V_oc=0.69 V, FF=0.69) under comparable conditions. When co‐adsorbed with chenodeoxycholic acid, the PCE of the best cyclometalated dye could be improved to 4.5 % (J_sc=9.4 mA cm^?2, V_oc=0.65 V, FF=0.70). The PCEs correlate well with the light‐harvesting capabilities of the dyes, while a comparable incident photon‐to‐current efficiency was achieved with the cyclometalated dye and the black dye. Regeneration appeared to be efficient in the parent dye, despite the high energy of the highest occupied molecular orbital. The device performance was investigated in more detail by electrochemical impedance spectroscopy. Ultimately, a promising Ru^II sensitizer platform is presented that features a highly functionalizable “click”‐derived cyclometalating ligand.     

Conjugated polymer consisting of dibenzosilole and quinoxaline as donor materials for organic photovoltaics

The new D–A type polymers poly(dibenzosilole-diphenylquinoxaline) (PSiPDTQ) and dibenzosilole-dibenzophenazine) (PSiFDTQ), both of which adopted benzosilole as a donor, were polymerized through a Suzuki coupling reaction. PSiPDTQ and PSiFDTQ were able to be dissolved in organic solvents and exhibited high thermal stability. Due to the appropriate LUMO energy levels, an effective charge transport was observed in PSiPDTQ and PSiFDTQ. According to X-ray diffraction measurements, a single broad diffraction peak was detected at approximately 20.5°. The π–π stacking distances (d_π) for PSiPDTQ and PSiFDTQ were 4.4 and 4.3 Å, respectively. When PSiPDTQ and PC₇₁BM were blended in a 1:3 ratio and used as the active layer in a solar cell, the resulting V_oc, J_sc, FF and PCE were 0.89 V, 5.1 mA/cm², 30.2% and 1.4%, respectively. For solar cells using a 1:6 ratio of PSiFDTQ to PC₇₁BM, the resulting V_oc, J_sc, FF and PCE were 0.98 V, 3 mA/cm², 52.8% and 1.6%, respectively. In addition, for a PSiPDTQ and PC₇₁BM blended film (1:3 ratio) with an additional layer of PFN, the PCE of the resulting solar cells was improved (relative to solar cells without PFN) to 2.1% due to the interfacial adhesion of PFN.     

Synthesis and Photovoltaic Properties of the Copolymers Based on Carbazole with Tetrathiophene Porphyrin Side Chains Linked by a Flexible Alkyl‐interval

Four copolymers (XP10, XP11, XP12 and XP13) based on diketopyrrolopyrrole (DPP) and carbazole units with tetrathiophene porphyrin (TTP) side chains linked by a flexible alkyl‐interval were designed and synthesized. The effects of the introduction of TTP on the optical and electrochemical properties, the morphology, the mobility and the photovoltaic performance of copolymers were systematically studied. The results revealed that XP11 with a TTP/DPP ratio of 2/8 possessed the best performances, i.e., broad absorption spectra, balanced hole/electron mobility and suitable microphase separation. After optimizing via solution vapor annealing, the organic solar cell devices based on XP11 and PC₇₁BM showed the best power conversion efficiency of 5.11% with a short‐circuit current density (J_sc) of 10.36 mA·cm^–2, an open‐circuit voltage (V_oc) of 0.77 V, and a fill factor (FF) of 0.64.     

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.