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Large-area uniform MoSe2@WSe2 HS prepared by EPD, achieves better catalytic activity, HER, and supercapacitor performance.

Assistive technology involving auditory feedback is generally utilized by those who are visually impaired or have speech and language difficulties. Therefore, here we concentrate on an auditory human-machine interface that uses audio as a platform for conveying information between visually or speech-disabled users and society. We develop a piezoresistive tactile sensor based on a black phosphorous and polyaniline (BP@PANI) composite by the facile chemical oxidative polymerization of aniline on cotton fabric. Taking advantage of BP’s puckered honeycomb lattice structure and superior electrical properties as well as the vast wavy fabric surface, this BP@PANI-based tactile sensor exhibits excellent sensitivity, low-pressure sensitivity, reasonable response time, and good cycle stability. For a real-world application, a prototype device employs six BP@PANI tactile sensors that correspond to braille characters and can convert pressed text into audio on reading or typing to assist visually or speech-disabled persons. Overall, this research offers promising insight into the material candidates and strategies for the development of auditory feedback devices based on layered and 2D materials for human-machine interfaces.

Mesoscopic photovoltaic devices (MPDs) are significantly promising for sustainable light-harvesting through solid-state compact designs. Materials with multifunctional properties play a vital role in improving the processability, stability, and cost of such devices. Here, a single-route synthesized sensitizer and multifunctional organic ionic plastic crystals (OIPCs) are introduced, and OIPCs are employed as a redox couple and light-harvesting contributor as a binary sensitizer-electrolyte system enabled via energy transfer in a photovoltaic device. Materials OIPC-I, OIPC-Br, and SK4 sensitizer possess a typical N-alkyl-phenoxazine (POZ)–N-alkyl-benzimidazole (BM)-type architecture, and OIPCs hold additional iodide and bromide anions at the quaternary nitrogen of BM. OIPCs show redox potential generated from anions corresponding to I−/I3− and Br−/Br3− as well as suitable molecular energy levels due to the POZ–BM donor–acceptor pathway, which results in a self-regenerative photovoltaic response in FTO/p-TiO2/OIPC/Pt configuration without any sensitizer. The SK4 sensitizer has suitable energy levels below the redox potential level of OIPCs, which are well regenerated by OIPCs during the photo-electricity generation in the photovoltaic device. Here, an OIPC–Br-based device with high photovoltage (0.98 (±0.02) V) and pronounced photocurrent from extra electrons gained through the POZ donor present in OIPC by the energy transfer mechanism shows 45% energy transfer towards the dye or TiO2. The OIPC-I based device demonstrated 43% (±3) higher efficiency compared to the conventional benzimidazolium-based electrolyte due to improved photocurrent and photovoltage. Single component OIPC-I based solid-state MPD devices show excellent ∼95% stability up to 5000 h, which is more than the OIPC–Br based device.

Two-dimensional (2D) transition metal dichalcogenide (TMDC) heterostructure is a new age strategy to achieve high electrocatalytic activity and ion storage capacity. The less complex and cost-effective applicability of the large-area TMDC heterostructure (HS) for energy applications require more research. Herein, we report the MoSe

Owing to the rise of miniaturized wearable electronic devices in the last decade, significant demands have arisen to obtain high-performance flexible supercapacitors (FSCs). Recently, a lot of research has been focused on developing smart components of FSCs and integrating them into new device configurations. In this work, FSCs based on a Ti3C2 nanosheet (NS) and an organic ionic conductor (OIC)-induced hydrogel as the electrode and the electrolyte, respectively, were used. The FSCs fabricated have three different configurations (sandwich, twisted fiber, and interdigitated) and a comparative study of their electrochemical performance was investigated in terms of cycle stability, bending stability, power density, and energy density. Finally, the experimental validation of practical application was conducted, which suggested excellent electrochemical stability of Ti3C2 NS FSCs for driven commercial electronic gadgets. This study presents mechanically robust, lightweight, high-performance FSCs, which can be assembled in different configurations for powering wearable electronic devices.

We report here the rational architecture of heteroanthracene-based metal-free organic D−π–A sensitizers (DS-1 and DS-2) and solid organic redox shuttles (ORSs) with common donor moieties phenothiaz...

Summary Direct utilization of abundantly available solar energy is a promising way to create a sustainable society. Here, we report a ferroelectric-semiconductor (BaTiO3@BiVO4) hybrid that uses an effective strategy to enhance charge separation and transfer during water oxidation. The tetragonal BaTiO3 can induce an outward vector of built-in electric field after positive polarization, which aids in increasing the photovoltage and accelerating holes’ transfer to BiVO4’s surface. A super-hygroscopic metal hydrogel serves as an atmospheric humidity harvester for continuous water supply to the hybrid, where water oxidation takes place. As the hydrogel absorbs moisture from ambient humid air, it functions as a dehumidifying agent and carries water to the photoanode for power generation, being connected in series with a solar cell, further boosting the carrier’s mobility. This photoanode-hydrogel and solar-cell intelligent assembly can generate a photocurrent of 0.4 mA/cm2 with a relative humidity reduction of 12.0% under an illumination of 10 mW/cm2.

Flexible supercapacitors (FSCs) have received a lot of interest as portable power sources for wearable electronics. The biocompatibility of electrodes and electrolytes in wearable FSCs is important to consider although research into these topics is still in its early stages. In this work, we developed a wearable FSC that uses MXene Ti

Many exciting developments have unfolded on the recently emerged research topic of solar-driven interfacial evaporation, which is a promising technology for water purification. However, the sole heat source, i.e., solar energy, has put a limit on the maximum achievable evaporation rate. Therefore, to boost the evaporation beyond the limit, we here in this work have put forth a new photothermal system with a trilayered structure (TLS) that is capable of simultaneously harvesting hybrid energy in addition to solar energy for enhanced evaporation. A carbon-based material with broad-band light absorption that can be facilely synthesized through dehydration effect is also reported. Demonstrations of TLS evaporator by recovering the free thermal energy from sources like ground surficial heat and waste heat from laboratory facility and building walls together with solar radiation have been carried out. A remarkable synergic evaporation rate exceeding 2.4 kg m-2 h-1 is achieved, and moreover, the hybrid heating makes evaporation independent of solar intermittency. Besides, a TLS integrated hybrid water-purification bottle with outstanding portability is further demonstrated, which is expected to be of great significance to the development of mobile water purification and safe water security in the future.

Low intensity indoor lightings are often wasted and unutilized, when they could be harvested to produce electrical energy. Unfortunately there is currently no solar cells which could harvest low light intensity efficiently. Therefore, this work reports the synthesis of energy transfer redox couples (ETRCs) that aid in the harvesting of low light intensity for photoelectrochemical cells. Such ETRCs are excellent choices as electrolytes in solid-state photoelectrochemical cells owing to their multifunctional attributes like faster dye regeneration, more efficient light absorption and faster energy transfer kinetics. Electrochemical characterizations reveal that Forster Resonance Energy Transfer (FRET) is occurring between ERTC electrolyte (donor) and the N719 dye (acceptor). Photovoltaic efficiency of the reported device is 28% higher than the conventional silicon solar cells, tested under low light intensity. Additionally, the idiosyncratic design of this device makes it versatile to be used in indoor conditions or can be mounted at a wide range of incidence angle with an ability to retain a high efficiency of 21.08%. Superior ionic-conductivity imparted by the single-component electrolyte provides a platform for future directions in energy harvesting and storage.

Five new triphenylamine (TPA) based D-π-A structural motifs were strategically designed and synthesized in high purity. The photophysical, electrochemical, photovoltaic properties were studied and the optimized geometry calculations of D-π-A chromophores and dyes were ascertained by DFT and TD-DFT methods. Photoluminescence properties of all the chromophores were studied in different organic solvents as well as in aggregated states. Three chromophores emit blue fluorescence in ethanol solution. However, two chromophores TPA-PHA [(E)-4′-(4-(diphenylamino)styryl)-[1,1′-biphenyl]-4-carbaldehyde], TPA-PFA [(E)-4′-(4-(diphenylamino)styryl)-2-fluoro-[1,1′-biphenyl]-4-carbaldehyde] exhibited Aggregation-induced emission enhancement (AIEE) revealing the formation of excimer in excited state. The TPA-PFA had lesser quantum yield than TPA-PHA in an aggregated state, since the m-fluorine substitution on phenyl containing chromophore makes an “inductive effect”. Substitution of aldehyde group causes enhanced formation of ICT from donor to acceptor. From FE-SEM analysis we concluded that both AIEE chromophores exhibit two different kinds of “nano-aggregates” in the solid state. The AIEE chromophores (TPA-PHA and TPA-PFA) and its derivatives i.e., Dye-1, Dye-2 were utilized in DSSC application for the first time. The dye-1 and dye-2 exhibit power conversion efficiencies (PCE) of 1.9% (Jsc = 4.68 mA/cm2, Voc = 0.70 V and FF = 0.59) and 2.1% (Jsc = 5.05 mA/cm2, Voc = 0.68 V and FF = 0.61), respectively.

Five (MA1-MA5) hemicyanine based sensitizer having N, N-diethyl aniline as a primary donor and hydroxy or alkoxy as an auxiliary donor have been synthesized to establish a correlation between amphiphilic nature of the sensitizer and charge recombination. A strong electron withdrawing 3-(carboxymethyl)-2-methylbenzo[d]thiazol-3-ium bromide has been explored as an acceptor. All the dyes were characterized by 1H-NMR, 13C-NMR and CHN analysis. The photophysical properties of these dyes were recorded in seven different solvents which do not show any significant impact on absorption and emission maxima while molar absorptivity coefficient decreases with increase in alkyl chain length. These dyes show very poor emission in all the solvents. Nano-crystalline mesoporous TiO2 based dye-sensitized solar cells were fabricated using MA1 to MA5 sensitizers to evaluate their photovoltaic performance. MA5 having six carbon alkyl chain shows maximum efficiency of 4.97% while MA1 without any alkyl chain shows the lowest efficiency of 3.40%. As the length of alkyl chain increase efficiency increase due to increment in short circuit current (Jsc) and retardation in the recombination process. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were explored to obtain vertical excitation, HOMO-LUMO energy and electron density distribution.

Six push–pull sensitizers (MD1 to MD6) having rhodanine-3-acetic acid acting as an electron withdrawing group and N-alkyl/aryl amine as a donor moiety were planned and prepared to rationalize the influence of donor alteration on absorption/emission properties and photon to current conversion efficiency (η). The structures of all the sensitizers were ascertained by 1H-NMR, 13C-NMR, mass spectroscopy and CHN analysis. The photophysical parameters of these sensitizers were recorded in nine solvents having different polarities to study the solvatochromic behavior of these dyes. Nanocrystalline mesoporous TiO2 based DSSCs were constructed by employing MD1 to MD6. The overall photon to current conversion efficiency was obtained in the range from 2.75% to 5.06% where the MD2 chromophore shows the highest efficiency of 5.06%. All efficiencies were correlated with the structural modification of the donor moiety to establish a structure–property relationship. The improved light to power conversion efficiency of MD2 is because of its high short circuit current Jsc (12.70 mA), high resistance in electron recombination and longer lifetime of injected electrons. The rigidity of the donor moiety (MD1) results in stabilization of the HOMO energy level, which increases the band gap and shows a decrease in efficiency along with a blue shift in the photophysical properties. N-Alkylation of the donor moiety (MD4–MD6) causes an increase in the molar absorptivity but affects the conjugation and shows a negative impact on efficiency. Lack of planarity in the pi-conjugation (MD3) has a negative impact on the photophysical and photovoltaic properties. An extensive DFT study reveals that the experimental absorption of all the dyes has very good correlation with theoretical vertical excitation obtained by time-dependent density functional theory (TD-DFT).

Flexible energy storage devices are becoming significantly important to power wearable and portable devices that monitor physiological parameters for many biomedical applications. Many hybrid nanomaterials based on 2D materials are used in order to improve the performance of flexible energy storage devices. Here, a hybrid nanocomposite is synthesized through in situ polymerization of aniline in the presence of black phosphorus (BP) nanoflakes. This nanocomposite, polyaniline (PANI)@BP, is employed to fabricate flexible supercapacitor (FSC) electrodes. PANI@BP FSCs can provide a power source for biometric devices. The generated signal can be transmitted to a smartphone in real time via wireless communication. Such a compact and lightweight integrated device has been used to track a human heart beat while powered by PANI@BP FSC. These findings are providing a promising example of a flexible energy storage device that can be integrated with different real-time health monitoring devices.

Nano/micromotor technology is evolving as an effective method for water treatment applications in comparison to existing static mechanisms. The dynamic nature of the nano/micromotor particles enable faster mass transport and a uniform mixing ensuring an improved pollutant degradation and removal. Here we develop thermosensitive magnetic nanorobots (TM nanorobots) consisting of a pluronic tri-block copolymer (PTBC) that functions as hands for pollutant removal. These TM nanorobots are incorporated with iron oxide (Fe

An evolving trend toward the ever-growing market of portable and wearable electronics has accelerated development in the construction of multifunctional energy generation and storage systems that can be twisted and folded to multiple deformations while retaining their electrochemical performance. The latest advances and well developed approaches for the design of heterocyclic solid-state organic ionic conductors (SOICs) in flexible energy generation and storage devices are discussed here. The development of SOICs with improved physical, optical, and electrochemical properties provides new prospects for flexible photoelectrochemical cells and supercapacitors. Equipped with a better knowledge of SOICs' multifunctional properties, researchers have made considerable progress in their development that allows modification according to the requirements of different types of flexible energy devices. Within this review, we highlight the design of efficient SOICs and their incorporation into flexible energy generation and storage devices, and address exciting instances that profile the multifunctionality of SOICs such as three-dimensional (3D) ionic channels, excellent thermal stability, dual functionality (hole/ions transportation), one-dimensional (1D) lamellar network, light-harvesting, and non-toxicity to mention a few. It is expected that innovative and customizable properties utilized in the development of multifunctional SOICs will provide a forum for future advancement in flexible and wearable energy generation and storage devices.

Photosynthetic proteins carry out photochemical charge separation with a near-unity quantum efficiency and provide interesting materials for sustainable solar energy conversion in man-made photoelectrochemical devices. The three-dimensional architectures of natural photosynthesisers on both macroscopic and microscopic length scales contrast strikingly with the essentially two-dimensional architectures of commercial photovoltaic devices. In this work we fabricated flexible and semi-transparent bio-photoelectrochemical cells (BPEC) that showed excellent flexibility and durability in response to repeated mechanical deformation. A three-dimensional stack of five such BPECs connected in parallel produced a peak photocurrent of 2900 nA under simulated sunlight in the laboratory and 2400 nA when tested outdoors. Placement of the BPEC stack within either a regular solid reflective well or a Johnson solid reflective well further boosted these photocurrents, computational analysis indicating that the strongest boost that more than doubled output was the consequence of multiple reflections within the Johnson solid that increased the light intensity incident on the BPEC stack. These design features, inspired by natural structures for absorbing and reflecting sunlight, improved the relative performance of the BPECs under non-peak insolation, such that the photocurrent output under natural sunlight was relatively uniform between 10 a.m. and 5 p.m. We discuss how the flexibility, durability and partial transparency of the individual BPECs enable the fabrication of cell arrays with a range of three-dimensional architectures.

Additive manufacturing technology, referred as 3D printing technology, is a growing research field with broad applications from nanosensors fabrication to 3D printing of buildings. Nowadays, the world is dealing with a pandemic and requires the use of simple sensing systems. Here, the strengths of fast screening by a lab-on-a-chip device through electrochemical detection using 3D printing technology for SARS-CoV-2 sensing are combined. This system comprises a PDMS microfluidic channel integrated with an electrochemical cell fully 3D-printed by a 3D printing pen (3D-PP). The 3D-PP genosensor is modified with an ssDNA probe that targeted the N gene sequence of SARS-CoV-2. The sensing mechanism relies on the electro-oxidation of adenines present in ssDNA when in contact with SARS-CoV-2 RNA. The hybridization between ssDNA and target RNA takes a place and ssDNA is desorbed from the genosensor surface, causing a decrease of the sensor signal. The developed SARS-CoV-2/3D-PP genosensor shows high sensitivity and fast response.

A series of low cost phenothiazine (PTZ) based small organic hole transporting materials (OHTMs) with high conductivity , hole mobility and low crystallinity were synthesized and systematically investigated for solid state photoelectrochemical cells/dye sensitized solar cells (DSSCs). Thermal, optical, photoelectrical and electrochemical properties of all OHTMs were evaluated using thermal techniques, cyclic voltammetry (CV), UV–vis absorption and other techniques. Density functional theory (DFT) was used to calculate optical and electrochemical properties of OHTMs and compared with experimental data. Role of these OHTMs in solid state photoelectrochemical cells with metal-free carbazole dye, SK3 in presence of additives like lithium bis(trifluoromethyl sulfonyl)imide salt (LiTFSI) and tert-butyl pyridine (TBP) are discussed along with the thickness of photoanode. In order to take an insight into photovoltaic performance , electron transfer kinetics and electron recombination in the OHTMs with different thickness of TiO 2 thin film based ss-DSSCs were characterized by I–V , electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD). The hole mobility, conductivity and photovoltaic performance of OHTMs are comparable with commercially available Spiro-OMeTAD. The highest power conversion efficiency ( PCE), 4.91% is achieved from thiophene substituted (at 3,6 positions) phenothiazine based SJH-11, is comparable with reference device incorporating Spiro-OMeTAD as HTM with SK3 sensitizer. All the ss-DSSCs with OHTMs exhibit good long-term stability under 1 sun illumination and ambient humidity conditions. The results are promising and have scope for improvement upon optimization of substitution at 3 and 6 positions of PTZ central/core moiety.

We have synthesized a novel solid organic ionic conductor (SOIC) that acts as a redox mediator and a light absorbing material at the same time. Such dual function of SOICs has not been reported before. It was achieved by substituting N,N′-dimethyl benzimidazolium iodide (BIMI) with hetero-anthracene (phenoxazine (POZ)/phenothiazine (PTZ)) which are labeled as SOIC-1 and SOIC-2, respectively. These substitutions caused the absorption spectrum of BIMI to be extended over 100 nm into the red spectrum and at the same time exhibit excellent redox capability and ionic conductivity. In addition, these synthesized SOICs also enhance the total electron injection into the TiO2 matrix with the metal-free SK3 dye sensitizer. Density functional theory (DFT) was used to optimize the structure and geometrical arrangement of the SOICs. To evaluate the role of PTZ/POZ substitution on BIMI and how pore filling can affect the device performance, solid-state DSSC (ss-DSSC) devices were prepared with two different thickness of TiO2 (8 μm and 12 μm) photoanode. The 8 μm thick TiO2 photoanode with SOIC-1 has an overall PCE of 7.9% which is about 72% higher than the unmodified BIMI (PCE of 4.4%) under AM1.5 illumination. Last but not least, the synthesized SOICs have high thermal stability up to 120 °C which is way beyond the operating temperatures of solar cells which make them ideal for real-world applications.

Four (MC1–MC4) 4-substituted coumarin dyes having N,N-diethyl aniline as donor and rhodanine-3-acetic acid as acceptor have been synthesized for use in nano-crystalline TiO2-based dye-sensitized solar cells (DSSCs). The alteration at the 4-position of coumarin was carried out by substituting H atom by chlorine (–Cl), piperidine (–NC5H10), and cyano group (–CN) to study the effect of substitution on the efficiency of the DSSCs. All the dyes were characterised by 1H-NMR and 13C-NMR spectroscopy and CHN analysis. The absorption and emission spectra of these coumarin dyes were recorded in eight different solvents and show positive solvatochromism. The TiO2-based DSSCs were fabricated using the four dyes and their photovoltaic properties were estimated. A maximum efficiency of 4.60% was obtained for the MC4 device, which has an electron-withdrawing cyano group at the 4-position of coumarin, while 2.64% efficiency was obtained for the MC1 device, which has only hydrogen at the 4-position. The efficiencies of the MC2 and MC3 devices lie between those of MC1 and MC4, suggesting the significance of substitution at the 4-position. The introduction of a cyano group, which acts as an electron trap, increases the electron-withdrawing capacity of the dye; thus, more electron density is withdrawn from the donor, resulting in enhanced efficiency. These dyes were studied by using density functional theory (DFT) and time dependent density functional theory (TD-DFT) to obtain the vertical excitation, HOMO–LUMO energy levels, band gap and electron distribution in the ground and excited state. The calculated values showed good correlation with the experimental values. Our results suggest that substitution at the 4-position is essential for enhancing the efficiency of coumarin-based DSSCs.

Photoelectrochemical solar cells have gained impetus over the past two decades owing to several advantages over conventional Si solar cells. The redox capabilities of the electrolyte play a major role in determining the overall photo-conversion efficiency (PCE) of dye sensitized solar cells. In this work we report a novel low toxicity and environmentally friendly aqueous organic ionic conductor (AOIC) for high efficiency DSSCs. This study presents the effect of water on the photocurrent density (Jsc) and stability of DSSCs. Interestingly we have also found that the addition of water to the OICs strongly alters the flat band potential (Efb) of nano-crystalline TiO2, hinders the recombination at the TiO2–AOIC interface and positively shifts the redox potential of I−/I3−. Under 1 sun illumination, OICs with 3-methoxypropionitrile solvent and OICs in water show a PCE of 6.02% and 3.57% respectively. This reduced PCE and J–V characteristics are attributed to the negative influence of water on the electron lifetime, electron recombination kinetics and the dark current. Substituting the electron withdrawing group present in the para-position of pyridinium salts mitigates the toxicity and enhances the cationic effect in the electrolyte. The DSSCs fabricated using AOICs showed excellent stability for more than 20 days.

Two novel thiophene 3,4-disubstituted organic dyes with double acceptors at 2,5-position framework photosensitizers were carefully designed and synthesized for the dye sensitized solar cell (DSSC) application. In this submission, the influence of carbazole (Cz) and triphenylaime (NPh3) units substitution at 3,4-position of thiophene is studied. Both the planar structure of carbazole based dyes and three dimension structure of triphenylamine based dyes are found to effectively inhibit the I − /I 3 − and Co +2 /Co +3 electrolyte on TiO 2 surface. The results show that varying the donor position in dyes also effectively works for DSSC application, even if it does not broaden the absorption peak in visible region (for both the dyes) due to the blocking of electron delocalization at 2,5-positions by acceptor units. With two twisted donors at 3,4-position in Cz-Th-Dye, NPh3-Th-Dye the dye aggregation and charge recombination retarded. The optical, electrochemical, density functional theory and TRPL studies were used to estimate the photovoltaic properties of the dyes. The dye having two acceptors on both sides (2,5-position) of thiophene moiety showed efficient electron extraction from the electron donor part. Without using any additives, Cz-Th dye and NPh3-Th dye in presence of cobalt (II/III) redox shuttle, resulted in the power conversion efficiency (η, PCE) of ∼3.4% and 3.1% respectively. By replacing one acceptor with any other donor, these thiophene moiety can effectively work as a new π-spacer in DSSC application.

The performance of DSSCs (dye sensitized solar cells) with a new series of dyes having different halide groups (i.e. F, Cl and Br) on o-position substituted phenyl spacers with same coumarin donor moieties have been reported. Optical, electrochemical, molecular orbital and photovoltaic properties were studied by varying the halide groups using these dyes. The replacement of halide atoms in same coumarin based dye had a significant effect on the short circuit current density (Jsc), open circuit voltage (Voc), and photo conversion efficiency (PCE). The Jsc and PCE of dye CD-1 (fluorine substituted) are 10.3 mA/cm2 and 5.2% respectively, which is higher than CD-2 (chlorine substituted) and CD-3 (bromine substituted) dyes (having PCE 4.1% and 3.5% respectively) devices. The optimized geometry calculation of o-halide phenyl π-spacer dyes were ascertained by density functional theory (DFT) using the B3LYP/6-31G(d,p) basis set. Moreover, we have checked the effect of various substituents in the same dye structure by DFT analysis.

Efficient electron donors, phenothiazine (PTZ)/phenoxazine (POZ) substituted imidazolium (IMI) and benzimidazolium (BIMI) iodide solid organic ionic conductors (SOICs) possessing good thermal stability and high conductivity are synthesized. The high conductivity arises due to the presence of the effective electron donor moiety PTZ/POZ and hence, these SOICs were used as single component solid electrolytes in solid state dye sensitized solar cells (ss-DSSCs). The ss-DSSC devices operate proficiently without any post-treatment to dye loaded TiO2 and additives in the electrolyte matrix. The presence of unsaturation and hetero-atoms in PTZ/POZ is responsible for the hole mobility and enhancement in light harvesting properties. Hence, when SOICs were excited along with a metal-free sensitizer, SK 1,the higher LUMO levels of SOICs increased the total electron injection in the TiO2 interface with the electrons of SK 1. Under illumination of solar light (100 mW cm−2 with an AM1.5G filter), ss-DSSCs with POZ substituted IMI and BIMI as single component solid electrolytes showed power conversion efficiency (PCE) of about 5.7%, which is quite comparable with the conventional imidazolium/benzimidazolium salt based liquid electrolytes and SK 1 sensitizer. The ss-DSSC devices with all four SOICs exhibit good long-term stability (∼1000 h) under 1 sun illumination and ambient humidity conditions. The present report paves the way for the development of single component solid organic ionic conductors having high electronic conductivity and better light harvesting ability as well as thermal stability.

Summary Dual attributes of UV-photo-responsive organic-ionic conductors are exploited in bio-photoelectrochemical cells based on photosynthetic RC-LH1 proteins from Rhodobacter sphaeroides. These UV enhancer molecules (UVEM) can generate small photocurrents in the absence of protein and are also effective electrolytes for photocurrent generation by RC-LH1 complexes in response to near-infrared excitation. Mixing RC-LH1 and UVEM components strongly enhanced UV photocurrents relative to those obtained with protein or UVEM alone, an effect that is attributed to energy transfer from the hetero-anthracene chromophore of the UVEM to the carotenoids of the RC-LH1 complex. RC-LH1/UVEM bio-photoelectrochemical cells were superior to conventional RC-LH1 cells in terms of UV external quantum efficiency, photo-response sensitivity, and photocurrent rise-decay times. These bio-photodetectors could detect weak UV radiation with intensities as low as 2 μW/cm2. This combination of photosynthetic proteins with dual-function electrolytes is the first attempt to construct fully functional bio-photoelectrochemical UV photodetector based on natural components.

The development of new technologies that use sunlight as an energy source is adding to pressure on finite natural resources and the challenges of recycling and disposal. Looking to nature for material assistance, we describe a proof-of-concept flexible and biodegradable photoelectrochemical cell based almost entirely on pigments, proteins, polysaccharides, and graphene platelets. In addition to being largely environmentally benign, such devices present opportunities for the recovery of valuable components such as, in the present case, the geologically scarce metal indium and the precious metal gold. Recovery is achieved through dissolution in ethanol followed by physical separation of the heavy element, leaving a residue made up from common elements that can be recycled through natural biodegradation. Potential applications for flexible, biomolecule-based photoelectrochemical cells are considered.

ZnS nanoparticles with Ni 2+ as dopant ions, have been synthesized and characterized by X-ray Diffraction, Inductive Coupled Plasma-Atomic Emission spectroscopy and Transmission Electron Microscopy. UV–vis absorption and photoluminescence spectroscopies were employed to investigate different photo-processes occurring on exposure to UV–vis light. The synthesized NPs were evaluated as photocatalyst for the removal of the color of aqueous solution of rhodamine B (RhB) dye as test solution under 250 W High Pressure Mercury Vapor lamp. Mott-Schottky, Cyclic Voltammetery, and hot-probe measurements suggest the change in the ‘type’ of semiconductor from n to p as well as phase change (cubic to wurtzite) take place on increasing the amount of dopant to 10%. The newly appeared phase forms ‘local pockets’ in an overall cubic matrix of ZnS NPs, this way created defects at the local grain boundaries of dissimilar phases. These provide active sites for the adsorption of dye molecules, in turn, improve the efficiency of the material as photocatalyst.

A series of new organic dyes based on fluorine substituted phenyl moiety, used as a π-linker in various dyes, were designed and synthesized for dye sensitized solar cell (DSSC) application. These dyes share same anchoring group (Cyano acrylic acid) with different donors such as carbazole, thiopene substituted carbazole, triphenylamine and phenothiazine moieties. For effective electron flow, the dyes were incorporated with novel D-π-A or D-A-A framework. The optical, electrochemical, time-resolved photoluminescence (TRPL) spectra and photovoltaic properties of the dyes were carefully studied. The results reveal that without addition of any co-adsorbent, among all fluoro-phenyl spacer dyes, the Cz-dye showed highest open circuit voltage (Voc), short circuit current (Jsc) and exhibited enhanced PCE value of 4.2 (±0.2) %, due to the deeper HOMO level of dye, planarity of backbone with better charge transfer occurring form D to A. The optimization calculations for the geometries of all the dyes with fluoro phenyl substituted π-linkers were ascertained by Density functional theory (DFT) using B3LYP/631G (d,p) basis set.

Summary This article addresses two major issues in the plasmonic dye solar cell; (i) protection of plasmonic nanoparticles from electrolyte attack and (ii) design of appropriate molecular dye to harvest photon near the plasmonic resonance. This report reveals the synthesis of D-π-A carbazole dye and incorporation of plasmonic Ag nanoparticles (AgNPs) into TiO 2 film using Ag–TiO 2 gel. We have designed and synthesized an efficient D-π-A carbazole dye molecule whose absorption maxima matches the plasmonic resonance of AgNPs leading to augmented near field effect, enhancing photon harvesting property of dye molecule. This article also describes a strategy to incorporate AgNPs into the TiO 2 photoelectrode by Ag–TiO 2 gel. The plasmonic photoanode was characterized using SEM and optical spectroscopy. Dye solar cells were characterized by J – V characteristics and electrochemical impedance technique in order to take insight into photovoltaic performance and electron transfer kinetic. This engineered DSSC achieves 45% enhancement in current due to the plasmon enhanced near field effect at thin film (3 μm).

Humic acid (HA), a natural polymer and soil component, was explored as a photosensitizer in dye-sensitized solar cells (DSSCs). Photophysical and electrochemical properties show that HA covers a broad visible range of the electromagnetic spectrum and exhibits a quasi-reversible nature in cyclic voltammetry (CV). Because of its abundant functionalities, HA was able to bind onto the nano-titania surface and possessed good thermal stability. HA was employed as a sensitizer in DSSCs and characterized by various photovoltaic techniques such as I–V, incident-photo-to-current conversion efficiency (IPCE), electrochemical impedance spectroscopy (EIS), and Tafel polarization. The HA-based device shows a power conversion efficiency (PCE) of 1.4% under 1 sun illumination. The device performance was enhanced when a coadsorbent, chenodeoxycholic acid (CDCA), along with HA was used and displayed 2.4% PCE under 0.5 sun illumination. The DSSCs employing HA with CDCA showed excellent stability up to 1000 h. The reported efficiency of devices with HA is better than that of devices with all natural sensitizers reported so far.

Half sandwich cationic mononuclear rhodium(III) and iridium(III) complexes [(η5-C5Me5)M(L)Cl]Cl·2H2O where L = dipyridylamine (dpa) (M = Rh, 1 and Ir, 2) and dipyridylketone (dpk) (M = Rh, 3 and Ir, 4) have been synthesized and characterized. The structure of a representative complex (1) was authenticated by single crystal X-ray diffraction analysis. Complexes 1–4 have been fully characterized by various physicochemical techniques, namely elemental analysis, spectral (IR, 1H, NMR, UV–Vis), electrochemical studies (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). Notably, the UV absorption spectral titrations of the synthesized complexes with DNA reveal that the complexes bind to calf thymus DNA (CT-DNA) through the intercalation mode. The DNA solution hydrodynamic volume (viscosity) measurements show that the interaction of the compounds with CT-DNA occurs by classical intercalation. A molecular docking study suggested intercalation between the synthesized compounds and nucleotide base pairs. Cyclic voltammetry studies of the complexes indicate irreversible oxidation and reduction potentials. A gel electrophoresis assay demonstrates the ability of the complexes to cleave pUC19 DNA. The antibacterial activities were assayed against selected Gram(−ve) and Gram(+ve) microorganisms. The cytotoxic properties of the metal complexes have been evaluated using a brine shrimp lethality bioassay. The results suggest that the binding affinity of 1–4 lies in the order 1 > 4 > 2 > 3.

The influence of TiO2 film thickness on the performance of DSSCs with a new series of dyes having ortho-fluorine substituted phenyl spacers and different donor moieties is reported. Optical, electrochemical, molecular orbital and photovoltaic properties were studied by varying the TiO2 thickness (9 and 12 μm) using these dyes. The thickness variation of TiO2 films had a significant effect on the open circuit voltage (Voc), short circuit current (Jsc) and efficiency. The Jsc and Voc of dye 1b with a TiO2 film thickness of 12 μm (8.91 mA cm−2 and 0.63 V) were larger than those of the 9 μm film thickness device (8.40 mA cm−2 and 0.57 V). This could be due to the variation in the thickness of the TiO2 film. However, at an optimized thickness of the TiO2 film (12 μm), 1b exhibited the highest power conversion efficiency (η) of 4.0% (average 3.6%). This highest efficiency value for 1b from 3.3% to 4.0% without using any co-absorbents was solely based on changing the thickness of the TiO2 film. In addition 1b had a planar structure, whereas dyes 2b and 3b had three and two dimensional structures. The optimized geometry calculation of o-fluoro phenyl π-spacer dyes was ascertained by density functional theory (DFT) using the B3LYP/631G(d,p) basis set. These results reveal that dye 1b has higher efficiency due to the deeper HOMO level and it exhibited better charge transfer from donor to acceptor, compared to the other dyes.

Natural photosynthetic proteins can convert solar energy into electrical energy with close to 100% quantum efficiency, and there is increasing interest in their use for sustainable photoelectrochemical devices. The primary processes of photosynthesis remain operational and efficient down to extremely low temperatures, and natural photosystems exhibit a variety of self-healing mechanisms. Herein we demonstrate the use of an amphiphilic triblock copolymer, Pluronic F127, to fabricate a self-healing photosynthetic protein photoelectrochemical cell that operates optimally at sub-zero temperatures. A concentration of 30% (w/w) Pluronic F127 depressed the freezing point of an electrolyte comprising 50 mM ubiquinone-0 in aqueous buffer such that optimal device solar energy conversion was seen at -12 °C rather than at room temperature. Fabrication of the protein photoelectrochemical cells with flexible electrodes enabled the demonstration of self-healing of damage caused by repeated mechanical deformation. Multiple bending cycles caused a marked deterioration of the photocurrent response to around a third of initial levels due to damage to the gel phase of the electrolyte, but this could be restored to ~95% by simply cooling and rewarming the device. This self-recoverability of the electrolyte extended the operational life of the protein cell through a process that increased its photoelectrochemical output during the repair. Utility of the cells as components of a touch sensor operational across a wide temperature range, including freezing conditions, is demonstrated.