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Alkylamines with different chain lengths including n-butylamine, n-hexylamine, and n-octylamine, are applied to regulate the CsPbIBr2 perovskite film quality by strain engineering. The status of residual strains is controllably modulated, resulting in improved efficiency and stability of carbon-based hole-transport-material free CsPbIBr2 perovskite solar cells. [ABSTRACT FROM AUTHOR]

Renewable energy utilization by energy conversion devices is regarded as a promising solution to resolve energy crisis and environmental pollution problems. Solar energy occupies 99% of the total energy of the Earth; therefore, the development of photovoltaic technology to convert solar energy into electricity is attracting considerable interests. The state-of-the-art research in this field mainly focuses on the improvement of power conversion efficiency under the sunlight irradiation by new materials development, device structure optimization, technique innovation, etc. In real natural environments, there is no or negligible sunlight for at least half of the time, particularly during rainy, foggy days or at night. Therefore, it is a challenging but promising strategy to develop new-type solar cells that can persistently harvest waste energies from nature without sacrificing the solar-to-electric conversion ability. In theory, these photovoltaics may break through the theoretical efficiency limitation and maximize the total power output. In this frontier article, the status quo of these physical proof-of-concept hybrid solar cells as well as the preparation methods of the solar cell architectures, and why harvesting waste energies are discussed. According to the working principles, the possible strategies of improving waste energy conversion efficiency are also envisaged. [ABSTRACT FROM AUTHOR]

Solar cells have been considered as one of the foremost solutions to energy and environmental problems because of clean, high efficiency, cost-effective, and inexhaustible features. The historical development and state-of-the-art solar cells mainly focus on elevating photoelectric conversion efficiency upon direct sunlight illumination. It is still a challenging problem to realize persistent high-efficiency power generation in rainy, foggy, haze, and dark-light conditions (night). The physical proof-of-concept for all-weather solar cells opens a door for an upcoming photovoltaic revolution. Our group has been exploring constructive routes to build all-weather solar cells so that these advanced photovoltaic technologies can be an indication for global solar industry in bringing down the cost of energy harvesting. How the all-weather solar cells are built without reducing photo performances and why such architectures can realize electricity outputs with no visible-light are discussed. Potential pathways and opportunities to enrich all-weather solar cell families are envisaged. The aspects discussed here may enable researchers to develop undiscovered abilities and to explore wide applications of advanced photovoltaics. [ABSTRACT FROM AUTHOR]

Creation of robust and stable electrocatalysts is a persistent objective for high-efficiency hydrogen evolution by water splitting. We present here the experimental realization of one-dimensional Mo incorporated W 18 O 49 nanofibers (NFs) by a template-free solvothermal method. When utilized as electrocatalysts for hydrogen evolution through water splitting, the preliminary results demonstrate that the optimized catalytic electrode from 1 at% Mo doped W 18 O 49 NFs yields an onset overpotential of 89 mV and Tafel slope of 49 mV dec −1 as well as maximal exchange current density up to 1.60 × 10 −2 mA cm −2 . An overpotential as low as 462 mV is required to attain current density of 50 mA cm −2 in comparison with 587 mV for pristine W 18 O 49 NFs. Moreover, the Mo doped W 18 O 49 NFs display relative stability by applying a potential of 503 mV and a current density of 80 mA cm −2 over 24 h in 0.5 M H 2 SO 4 aqueous solution, making them promising in practical applications. [ABSTRACT FROM AUTHOR]

We report here robust electrocatalysts from metal doped W18O49 nanofibers (NFs) for high-efficiency hydrogen evolution. By tuning Pd dosages, the optimal 5 at% Pd doped W18O49 NFs yield an onset overpotential of only 65 mV and exchange current densities up to 2.36 × 10−3 mA cm−2. Moreover, the resultant electrocatalyst is relatively stable during persistent operation. [ABSTRACT FROM AUTHOR]

Application-specific requirements for future perovskite solar cells include lightweight, mechanical resilience, and deformability for multi-purpose utilizations ranging from electronic skin and implant in the body to wearable textiles. Here we demonstrate the experimental realization of intrinsically bendable, stretchable, twistable, and compressible perovskite solar cells made by adsorbing hole-transporting polyaniline, solvothermal-processed halide (5-AVA) y (CH 3 NH 3 ) 1−y PbI 3 or (5-AVA) y (CH 3 NH 3 ) 1−y PbI 3−x Cl x precursor as well as electron-transporting [6,6]-phenyl-C61-butyric acid methyl with three-dimensional amphiphilic gel matrix. The multi-deformable perovskite solar cell with CH 3 NH 3 PbI 3 crystals yields a power conversion efficiency of 3.62% at undeformed state and AM1.5 G sunlight irradiation, while the efficiency can increase to 4.51% at a bending angle of 140°, to 4.46% at an elongation of 220%, to 5.10% at a twist angle of 360°, and to 5.57% at a compression ratio of 80%. After hundreds of arbitrary deformations, the solar cell still remains ~130% efficiency. Owing to an amphiphilic surface, the solar cell is relatively stable for 7 days when exposed in 78%-humidity ambient air. This work represents a significant step forward, as it realizes the solvothermal synthesis of halide CH 3 NH 3 PbX 3 (X=I, Cl) precursors and low-temperature fabrication, arbitrary deformations without sacrificing power conversion efficiency along with promising humidity-resistance in ambient atmosphere for perovskite solar cells. [ABSTRACT FROM AUTHOR]

Solar cells that can harvest energy in all weathers are promising in solving the energy crisis and environmental problems. The power outputs are nearly zero under dark conditions for state-of-the-art solar cells. To address this issue, we present herein a class of platinum alloy (PtM x, M=Ni, Fe, Co, Cu, Mo) tailored all-weather solar cells that can harvest energy from rain and realize photoelectric conversion under sun illumination. By tuning the stoichiometric Pt/M ratio and M species, the optimized solar cell yields a photoelectric conversion efficiency of 10.38 % under simulated sunlight irradiation (AM 1.5, 100 mW cm−2) as well as current of 3.90 μA and voltage of 115.52 μV under simulated raindrops. Moreover, the electric signals are highly dependent on the dripping velocity and the concentration of simulated raindrops along with concentrations of cation and anion. [ABSTRACT FROM AUTHOR]

Solar cells that can harvest energy in all weathers are promising in solving the energy crisis and environmental problems. The power outputs are nearly zero under dark conditions for state-of-the-art solar cells. To address this issue, we present herein a class of platinum alloy (PtM x, M=Ni, Fe, Co, Cu, Mo) tailored all-weather solar cells that can harvest energy from rain and realize photoelectric conversion under sun illumination. By tuning the stoichiometric Pt/M ratio and M species, the optimized solar cell yields a photoelectric conversion efficiency of 10.38 % under simulated sunlight irradiation (AM 1.5, 100 mW cm−2) as well as current of 3.90 μA and voltage of 115.52 μV under simulated raindrops. Moreover, the electric signals are highly dependent on the dripping velocity and the concentration of simulated raindrops along with concentrations of cation and anion. [ABSTRACT FROM AUTHOR]

Precious platinum counter electrode (CE) has been an economic burden for future commercialization of dye-sensitized solar cells (DSSCs). Low-platinum alloy CE catalysts are promising in bringing down the solar cell cost without reducing photovoltaic performances. We present here a facile strategy of fabricating ZnO nanorods assisted platinum-nickel (PtNi) alloy microtube CEs for liquid-junction DSSCs. By adjusting the concentration of zinc precursors, the ZnO nanostructures and therefore PtNi alloys are optimized to maximize the electrocatalytic behaviors toward triiodide reduction reaction. The maximal power conversion efficiency is determined as high as 8.43% for liquid-junction DSSC device with alloyed PtNi microtube CE synthesized at 75 mM Zn(NO 3 ) 2 aqueous solution, yielding a 32.8% enhancement in cell efficiency in comparison with the solar cell from pristine platinum electrode. Moreover, the dissolution resistance and charge-transfer ability toward redox couples have also been markedly enhanced due to competitive dissolution reactions and alloyed effects. [ABSTRACT FROM AUTHOR]

Seawater splitting by complicated electrocatalytic processes is promising for hydrogen evolution. Here we present a series of robust electrodes by electrodepositing RuCo and RuCoMo x alloys on Ti foil substrates for hydrogen evolution from seawater splitting. The preliminary results demonstrate that Ti foil supported RuCo and RuCoMo x alloy electrodes require overpotentials of ∼387 and ∼550 mV to drive the hydrogen evolution reaction (HER) at a benchmark current density of 10 mA cm −2 , respectively. Moreover, the resultant Ti foil supported RuCoMo x electrode shows excellent stability under persistent operation at a constant current density of −1.2 V over 12 h. [ABSTRACT FROM AUTHOR]

Creation of transparent counter electrode (CE) electrocatalysts for bifacial dye-sensitized solar cells (DSSCs) is a persistent objective for reducing cost of photovoltaic conversion. We present here the experimental realization of highly transparent CuSe CEs by a mild solution method for liquid-junction bifacial DSSCs. The resultant CuSe CEs show superior electrocatalytic activity toward I 3 − reduction reaction. By optimizing the pH values in synthesizing CuSe electrodes, the maximal front efficiency of 6.21% and rear efficiency of 4.72% are recorded on the corresponding bifacial DSSC. Both catalytic activity and photovoltaic performances can be further elevated by alloying CuSe with Co or Fe, yielding promising efficiencies of 7.81% and 5.38% under front and rear irradiations, respectively. [ABSTRACT FROM AUTHOR]

All-weather solar cells are promising in solving the energy crisis. A flexible solar cell is presented that is triggered by combining an electron-enriched graphene electrode with a dye-sensitized solar cell. The new solar cell can be excited by incident light on sunny days and raindrops on rainy days, yielding an optimal solar-to-electric conversion efficiency of 6.53 % under AM 1.5 irradiation and current over microamps as well as a voltage of hundreds of microvolts by simulated raindrops. The formation of π-electron|cation electrical double-layer pseudocapacitors at graphene/raindrop interface is contributable to current and voltage outputs at switchable charging-discharging process. The new concept can guide the design of advanced all-weather solar cells. [ABSTRACT FROM AUTHOR]

All-weather solar cells are promising in solving the energy crisis. A flexible solar cell is presented that is triggered by combining an electron-enriched graphene electrode with a dye-sensitized solar cell. The new solar cell can be excited by incident light on sunny days and raindrops on rainy days, yielding an optimal solar-to-electric conversion efficiency of 6.53 % under AM 1.5 irradiation and current over microamps as well as a voltage of hundreds of microvolts by simulated raindrops. The formation of π-electron|cation electrical double-layer pseudocapacitors at graphene/raindrop interface is contributable to current and voltage outputs at switchable charging-discharging process. The new concept can guide the design of advanced all-weather solar cells. [ABSTRACT FROM AUTHOR]

Creation of cost-effective and platinum-free counter electrodes (CEs) is persistent for developing advanced dye-sensitized solar cells (DSSCs). We present here the fabrication of conducting polymers such as polyaniline (PANi), polypyrole (PPy), or poly(3,4-ethylenedioxythiophene) (PEDOT) intercalated reduced graphene oxide (rGO) CEs on flexible Ti foil or polyethylene-terephthalate substrate for liquid-junction DSSC applications. The ration architecture integrates the high electron-conducting ability of graphene and good electrocatalytic activity of a conducting polymer into a single CE material. The preliminary results demonstrate that the resultant CEs follow an order of rGO/PPy > rGO/PANi > rGO/PEDOT > rGO. A maximal cell efficiency of 6.23% is determined on the optimized solar cell device, yielding 104.9% enhancement in comparison to rGO based device. [ABSTRACT FROM AUTHOR]

We present here the realization of cylindrical dye-sensitized solar cells composed of Ti wire supported TiO2 nanotube anodes and transparent metal selenide counter electrodes. The optimized device yields a high efficiency of 6.63%, good stability over time, and identical efficiency output at arbitrary incident angles. [ABSTRACT FROM AUTHOR]

One of the challenges in developing advanced dye-sensitized solar cells (DSSCs) is the pursuit of cost-effective and robust counter electrodes (CEs). We present here the successful synthesis of binary Pt x M 100−x (M = Ni, Co, Fe) alloy nanostructures on Ti foil by a facile and environmental-friendly strategy for utilization as CEs in liquid-junction DSSCs. Due to the reasonable charge-transfer ability and excellent electrocatalytic activity, the resultant DSSC yields a promising power conversion efficiency (PCE) of 6.42% with binary Pt 0.28 Ni 99.72 CE in comparison with 6.18% for pristine Pt CE based device. The easy synthesis, cost-effectiveness, and good electrocatalytic property may help the Pt 0.28 Ni 99.72 nanostructure stand out as an alternative CE electrocatalyst in a DSSC. [ABSTRACT FROM AUTHOR]

Counter electrode (CE) is crucial in catalyzing triiodide reduction reaction and therefore in enhancing power conversion efficiency of a dye-sensitized solar cell (DSSC). We present here the alloying of Pt with Ni microtubes and Co nanosheets for cost-effective CE electrocatalyst using ZnO microrod templates. In comparison with pristine Pt electrode, the resultant PtNiCo alloy CE displays significantly elevated electrocatalytic activity and charge transfer ability, yielding an impressive efficiency of 8.85% in its liquid-junction DSSC platform. [ABSTRACT FROM AUTHOR]

A class of alloyed Pd–Co catalysts are prepared by a mild solution method and subsequently blended with poly(vinylidene fluoride) (PVDF) binder for coating cost-effective counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). The electrocatalytic activity for the I − /I 3 − redox electrolyte as well as photovoltaic performances of DSSCs are optimized by adjusting stoichiometric Pd/Co ratios. Due to the merits of resultant Pd–Co alloy CEs on good electrical conduction, rapid charge-transfer ability, and increased electrocatalytic activity, a maximum conversion efficiency of 6.44% is determined on the optimized DSSCs in comparable to 6.18% for Pt CE based DSSC. It is obvious that Pd–Co alloy CEs can be a better cost-effective and efficient alternative due to the expensive price and scarcity of Pt for the large scale applications of DSSCs. [ABSTRACT FROM AUTHOR]

Creation of dissolution-resistant counter electrodes (CEs) is a long-term objective for searching advanced dye-sensitized solar cell (DSSC) platforms. We present here the electrochemical deposition of PtM 0.1 (M = Fe, Co, Ni) alloy CEs and understanding of the dissolution-resistance by thermodynamical calculation. On behalf of interaction between host Pt and guest M atoms, the electrocatalytic activity of alloyed PtM 0.1 CEs is markedly enhanced in comparison with pristine Pt electrode. The competitive dissolution reactions from guest M atoms and liquid electrolyte contribute to the long-term stability of PtM 0.1 alloy CEs. Compared with the liquid-junction DSSC from pristine Pt CE, the solar cells with PtNi 0.1 , PtCo 0.1 , and PtFe 0.1 alloy CEs represent remarkable power conversion efficiencies of 8.77%, 8.26% and 7.84%, respectively. These PtM 0.1 CEs show great promise for commercial application as they allow for a maximum 21.8% improvement in cell efficiency in comparison to the Pt CE system without compromising device stability. [ABSTRACT FROM AUTHOR]

Pt counter electrode (CE) has been a burden for the commercialization of liquid-junction dye-sensitized solar cells (DSSCs). In searching for cost-effective CEs without sacrificing electrochemical activities, here we report the experimental realization of ZnO nanorods assisted Ni 1.1 Pt and Co 3.9 Pt alloy microtube (MT) CEs by combining a simple electrodeposition deposition on aligned ZnO nanorods and a galvanic displacement reaction. On behalf of the good charge-transfer ability along one-dimensional alloy electrocatalyst and electrocatalytic activity toward liquid electrolyte, the resultant DSSCs with Ni 1.1 Pt and Co 3.9 Pt MT CEs display promising power conversion efficiencies of 8.29% and 7.73%, yielding 30.6% and 21.7% enhancements, respectively. Similarly importantly, the alloyed CEs are still scalable, other alloyed low-Pt or non-Pt nano/microstructures can also be realized using the method reported here. [ABSTRACT FROM AUTHOR]

In order to enhance photovoltaic performances and to reduce fabrication cost of liquid-junction dye-sensitized solar cells (DSSCs), here we report platinum alloy decorated polyaniline (PANi/MPt, M = Mo, Pd, Co) counter electrodes (CEs) by an electrochemical deposition method. In comparison with pristine PANi electrode, the integration of PANi with MPt alloys markedly enhances the electrocatalytic activity towards I 3 − reduction reaction. The power conversion efficiencies of 8.08%, 7.26% and 6.83% are determined from DSSCs employing PANi/CoPt, PANi/PdPt, and PANi/MoPt CEs, respectively [ABSTRACT FROM AUTHOR]

A rising objective for high-efficiency dye-sensitized solar cells (DSSCs) is to create extraordinary and cost-effective counter electrode (CE) electrocatalysts. We present here a branching NiCuPt alloy CE synthesized by electrodepositing Ni on ZnO microrod templates and subsequently growing branched Cu as well as suffering from a galvanic displacement for Pt uptake. The resultant NiCuPt alloy CE displays a promising electrocatalytic activity toward redox electrolyte having I − /I 3 − couples. An impressive power conversion efficiency of 9.66% is yielded for the liquid-junction DSSC platform. [ABSTRACT FROM AUTHOR]

Pursuit of cost-effective counter electrode (CE) electrocatalysts with no sacrifice of photovoltaic performances has been a persistent objective for advanced dye-sensitized solar cell (DSSC) platforms. Here we demonstrate the experimental realization of CE electrocatalysts from Cu@M@Pt (M = Fe, Co, Ni) coaxial alloy nanowires for efficient DSSCs. The reasonable electrocatalytic activity is attributed to work function matching of alloy CEs to potential of I − / I 3 − and redistribute the electronic structure on the Pt surface. In comparison with 8.48% for the Pt nanotube CE based DSSC, the solar cells yield power conversion efficiencies up to 8.21%, 7.85%, and 7.30% using Cu@Fe@Pt, Cu@Co@Pt, and Cu@Ni@Pt NWs, respectively. This work represents an important step forward, as it demonstrates how to make the CE catalyst active and to accelerate the electron transport from CE to electrolyte for high-efficiency but cost-effective DSSC platforms. [ABSTRACT FROM AUTHOR]

Bifacial dye-sensitized solar cell (DSSC) is a promising solution to reduce the cost of photovoltaic conversion. We present here the experimental realization of bifacial quasi-solid-state DSSC from a TiO 2 photoanode, a semitransparent gel electrolyte, and a Ti grid supported metal selenide (MSe, M = Co, Ni, Ru) counter electrode (CE). In comparison with front efficiency of 4.87% and rear efficiency of 1.19% for Ti grid supported Pt based DSSC, the efficiencies are enhanced to 6.51% and 1.84% on the solar cell with cost-effective Ti grid supported RuSe CE. The preliminary results demonstrate that this architecture is promising in realizing cost-effective bifacial quasi-solid-state DSSCs without sacrificing photovoltaic performances. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cell (DSSC) is a promising solution to energy depletion, environmental pollution, and ecological destruction. In this communication, we have successfully prepared nanoporous titanium dioxide (TiO 2 ) framework by etching traditional TiO 2 nanoparticle film for DSSC applications. Due to the enhancement in light-scattering and fast electron transport, a promising power conversion efficiency of 8.29% is recorded from the DSSC employing TiO 2 nanoframework in comparison with 6.24% for the solar cell with pristine TiO 2 anode. [ABSTRACT FROM AUTHOR]

Aiming at reducing fabrication cost without sacrificing power conversion efficiency (PCE) of dye-sensitized solar cell (DSSC), transparent palladium selenide (Pd–Se) alloys are prepared by a cyclic voltammetric electrodeposition and utilized as counter electrodes (CEs) in bifacial DSSCs. The electrocatalytic activities of Pd–Se alloy CEs with adjustable stoichiometries are investigated, yielding an optimized alloy electrode at Pd 7 Se 4 . The PCE of the bifacial DSSC based on Pd 7 Se 4 alloy CE shows front and rear efficiencies of 6.70% and 2.38% in comparison with 6.43% and 0.01% from pyrolytic platinum based solar cell, respectively. The results demonstrate that the Pd 7 Se 4 alloy CE can serve as a good candidate for CE in DSSCs application. [ABSTRACT FROM AUTHOR]

Pursuit of an efficient strategy for quantum dot-sensitized photoanode has been a persistent objective for enhancing photovoltaic performances of quantum dot-sensitized solar cell (QDSC). We present here the fabrication of the indium sulfide (In 2 S 3 ) quantum dot-sensitized titanium dioxide (TiO 2 ) photoanode by combining successive ionic layer adsorption and reaction (SILAR) with solvothermal processes. The resultant QDSC consists of an In 2 S 3 sensitized TiO 2 photoanode, a liquid polysulfide electrolyte, and a Co 0.85 Se counter electrode. The optimized QDSC with photoanode prepared with the help of a SILAR method at 20 deposition cycles and solvothermal method yields a maximum power conversion efficiency of 1.39%. [ABSTRACT FROM AUTHOR]

Pursuit of cost-effective counter electrode (CE) electrocatalysts with no sacrifice of photovoltaic performances has been a persistent objective for dye-sensitized solar cells (DSSCs). Here we demonstrate the galvanic replacement realization of cost-effective CEs from Fe@M (M = Pd, Pt) nanospheres for DSSCs. Due to the enhanced catalytic activity originated from compressive strain and extended surface in tuning the electronic structure of Pd (or Pt) shell along with competitive dissolution reaction of Fe with electrolyte, the cells with high durability display efficiencies of 8.74% and 7.22%. The impressive results along with simple synthesis highlight the potential application of Fe@M nanospheres in robust DSSCs. [ABSTRACT FROM AUTHOR]

Alloys are a class of rising counter electrode (CE) electrocatalyst candidates for dye-sensitized solar cells (DSSCs). We present here the mild solution synthesis of NiM (M = Pt, Pd) alloys using zinc oxide nanorod templates and employment as CE electrocatalysts for liquid-junction DSSC applications. Due to the good matching of work functions to redox potential of I − /I 3 − redox couples and reduced charge-transfer resistance at CE/electrolyte interface, the electrocatalytic activity of NiPt CE and therefore cell performances have been markedly enhanced, yielding a promising power conversion efficiency of 8.27% in the liquid-junction DSSC platform. [ABSTRACT FROM AUTHOR]

Enhancement of light harvesting has been a persistent objective for elevating dye excitation and therefore power conversion efficiency of dye-sensitized solar cells (DSSCs). Here we launch a strategy of markedly enhancing light harvesting by caging TiO 2 nanoparticles with curved silica microsheets. The results show that the strategy is versatile in suppressing the recombination reaction of electrons with I 3 − species in liquid electrolyte. Due to the superior reflective behaviors of curved silica microsheets, an optimal efficiency of 9.22% is recorded under simulated air mass 1.5 global sunlight on the DSSC in comparison with 6.51% and 7.51% from pristine TiO 2 and planar silicate microsheet incorporated TiO 2 photoanode based solar cells, respectively. This strategy is also believed to be applicable to other solar cells such as perovskite solar cells and quantum dot-sensitized solar cells. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cell (DSSC) has been considered as a potentially cost-effective alternative to silicon solar cell. By optimizing three components of a typical DSSC including a dye-sensitized wide-bandgap semiconductor photoanode for creating and transporting electrons, n redox electrolyte, and a counter electrode (CE) for reducing oxidized species in electrolyte, a maximum power conversion efficiency of 13% has been determined. The high cost of DSSCs is to a large part dictated by the high loading of Pt required to catalyze the triiodide reduction reaction. Arguably one of the arising routes to reduce fabrication cost of DSSCs with no sacrifice of catalytic activity of CEs is to alloy Pt with other metals/nonmetals or to replace Pt with Pt-free alloys. In this perspective paper, we outline the advances of alloy CEs in comparison with other alternatives such as carbonaceous materials and conductive polymers and their hybrids including design concepts, fabrication approaches, and properties. Finally, this review launches prospects and challenges of promising alloy CEs for their applications in high-efficiency DSSCs. [ABSTRACT FROM AUTHOR]

The dissolution of platinum (Pt) has been one of the heart issues in developing advanced dye-sensitized solar cells (DSSCs). We present here the experimental realization of stable counter-electrode (CE) electrocatalysts by alloying Pt with transition metals for enhanced dissolution resistance to state-of-the-art iodide/triiodide (I−/I3−) redox electrolyte. Our focus is placed on the systematic studies of dissolution engineering for Pt M0.05 ( M=Ni, Co, Fe, Pd, Mo, Cu, Cr, and Au) alloy CE electrocatalysts along with mechanism analysis from thermodynamical aspects, yielding more negative Gibbs free energies for the dissolution reactions of transition metals. The competitive reactions between transition metals with iodide species (I3−, I2) could protect the Pt atoms from being dissolved by redox electrolyte and therefore remain the high catalytic activity of the Pt electrode. [ABSTRACT FROM AUTHOR]

The dissolution of platinum (Pt) has been one of the heart issues in developing advanced dye-sensitized solar cells (DSSCs). We present here the experimental realization of stable counter-electrode (CE) electrocatalysts by alloying Pt with transition metals for enhanced dissolution resistance to state-of-the-art iodide/triiodide (I−/I3−) redox electrolyte. Our focus is placed on the systematic studies of dissolution engineering for Pt M0.05 ( M=Ni, Co, Fe, Pd, Mo, Cu, Cr, and Au) alloy CE electrocatalysts along with mechanism analysis from thermodynamical aspects, yielding more negative Gibbs free energies for the dissolution reactions of transition metals. The competitive reactions between transition metals with iodide species (I3−, I2) could protect the Pt atoms from being dissolved by redox electrolyte and therefore remain the high catalytic activity of the Pt electrode. [ABSTRACT FROM AUTHOR]

Pursuit of a high efficiency and stability has been a persistent objective for quantum dot-sensitized solar cells (QDSCs). Here we launch a strategy of synthesizing graphene implanted polyacrylamide (PAAm-G) conducting gel electrolytes for quasi-solid-state QDSCs. With an aim of elevating the dosage of S 2− /S x 2− redox couples and therefore charge-transfer ability, both osmotic press across the PAAm-G and capillary force within the three-dimensional micropores are utilized as driving forces. A promising power conversion efficiency of 2.34% is recorded for the QDSCs by optimizing graphene dosage in the conducting gel electrolyte. The enhanced conversion efficiency of solar cell is attributed to the expanded catalytic area from counter electrolyte/electrolyte interface to both interface and the conducting gel electrolyte. [ABSTRACT FROM AUTHOR]

High power conversion efficiency and cost-effectiveness are two persistent objectives for dye-sensitized solar cell (DSSC). Electricity generation from either front or rear side of a bifacial DSSC has been considered as a facile avenue of bringing down the cost of solar-to-electric conversion. Therefore, the fabrication of a transparent counter electrode (CE) with a high electrocatalytic activity is a prerequisite to realize this goal. We present here the feasibility of utilizing transparent cobalt selenide (Co–Se) binary alloy counter electrode for bifacial DSSC application, in which binary Co–Se alloy electrode is synthesized by a mild solution strategy and the cell device is irradiated by either front or rear side. Due to the high optical transparency, charge-transfer ability, and electrocatalytic activity, maximum front and rear efficiencies of 8.30% and 4.63% are recorded under simulated air mass 1.5 (AM1.5) irradiation, respectively. The impressive efficiency along with fast start-up, multiple start capability, and simple preparation highlights the potential application of cost-effective and transparent Co–Se alloy CE in robust bifacial DSSCs. [ABSTRACT FROM AUTHOR]

Pursuit of cost-effective and efficient counter electrodes (CEs) is a persistent objective for dye-sensitized solar cells (DSSCs). We present here the design of transparent Fe–Se nanoporous alloy CEs for bifacial DSSC applications. Due to the superior charge-transfer ability for I − /I 3 − redox couples, electrocatalytic reduction toward I 3 − species, and optical transparency in visible-light region, the bifacial DSSC with FeSe alloy electrode yields maximum front and rear efficiencies of 9.16% and 5.38%, respectively. A fast start-up, high multiple start capability, and good stability of the FeSe alloy CE demonstrate the potential applications in driving solar panels. The impressive efficiency along with simple preparation of the cost-effective Fe–Se nanoporous alloy CEs highlights their potential application in robust bifacial DSSCs. [ABSTRACT FROM AUTHOR]

Elevation of power conversion efficiency and reduction of electricity-generation cost have been two persistent objectives for quantum dot-sensitized solar cells (QDSSCs). Here we report a bifacial QDSSC structure having impressive power conversion efficiencies of 2.11% and 1.28% for front and rear irradiations, respectively. The device comprises a CdS-sensitized TiO 2 anode, a transparent cobalt selenide (Co–Se) counter electrode (CE), and a liquid electrolyte containing S 2− /S n 2− redox couples. Due to high optical transparency of the binary Co–Se alloy CE, incident light can penetrate the QDSSC from either front or rear side for electron excitation. A fast start-up and modest photocurrent stability are determined in the bifacial QDSSCs due to the high electron transfer kinetics in CdS-sensitized TiO 2 photoanode and electrocatalytic kinetics in Co–Se CE. [ABSTRACT FROM AUTHOR]

Pursuit of cost−effective and efficient counter electrodes (CEs) has been a persistent objective for dye−sensitized solar cells (DSSCs). Aiming at reducing fabrication cost without sacrificing power conversion efficiency of DSSCs, here we report the successful design of binary Pt–Ni alloy CEs by a simple cyclic voltammetry technique. Due to the rapid charge transfer ability and electrocatalytic activity, the power conversion efficiency of the DSSC employing binary PtNi 0.75 alloy CE has been elevated to 8.59% in comparison with 6.98% from Pt−based solar cell. The impressive results along with simple synthesis highlight the potential application of low−Pt alloys in robust DSSCs. [ABSTRACT FROM AUTHOR]

Pursuit of a high power conversion efficiency and reduction of electricity-generation cost has been a persistent objective for quantum dot-sensitized solar cells (QDSSCs). We present here the fabrication of a QDSSC comprising a nanoflower-structured CdS anode, a liquid electrolyte having S 2− /S n 2− redox couples, and a transparent CoSe counter electrode. Nanoflower-structured CdS anodes are prepared by a successive ionic layer adsorption and reaction (SILAR) method and subsequently hydrothermal strategy free of any surfactant or template. The CdS nanoparticles synthesized by a SILAR method act as “seed crystal” for growth of CdS nanoflowers. The average electron lifetime is markedly elevated in nanoflower-structured CdS anode in comparison with CdS nanoparticle or nanoporous CdS microsphere anode. Herein, we study the effect of synthesis method on CdS morphology and solar cell's photovoltaic performance, showing a power conversion efficiency of 1.67% and 1.17% for nanoflower-structured CdS QDSSC under front and rear irradiations, respectively. [ABSTRACT FROM AUTHOR]

We present here the feasibility of growing well-aligned TiO2 nanorod arrays by a dc reactive magnetron sputtering strategy for flexible dye-sensitized solar cells. These flexible devices yield an efficiency of 5.3% in comparison to 1.2% from traditional TiO2 nanoparticles by a low-temperature technique. [ABSTRACT FROM AUTHOR]

Enhancement of light harvest for dye excitation is a persistent objective in dye-sensitized solar cell (DSSC). We present here the fabrication of titanium dioxide/calcium fluoride (TiO 2 /CaF 2 ) photoanodes for efficient DSSC applications. Owing to the interference effect of incident light beams reflected from TiO 2 /CaF 2 and CaF 2 /electrolyte interfaces, the light intensity and therefore dye excitation have been markedly enhanced. The crystal structure and therefore photovoltaic performance are optimized by adjusting CaF 2 dosage. A maximum power conversion efficiency of 7.66% is measured from the DSSC employing TiO 2 /0.5 wt% CaF 2 nanocrystallite in comparison with 6.02% for the solar cell with pristine TiO 2 anode. [ABSTRACT FROM AUTHOR]

Alloy materials have established themselves as alternative electrocatalysts for electrochemical devices because of their cost-effectiveness, high conductivity, good electrocatalytic activity, and reasonable stability. Aiming at reducing fabrication cost without sacrificing power conversion efficiency of dye-sensitized solar cells (DSSCs), we report the feasibility of designing transparent and cost-effective Fe–Se alloy counter electrodes for bifacial DSSCs. Due to the rapid charge transfer ability and electrocatalytic activity, maximum front and rear efficiencies of 7.64% and 4.95% are measured for the DSSC with FeSe alloy electrode in comparison with 6.97% and 3.56% from Pt-based solar cell. The impressive results along with simple synthesis highlight the potential application of Fe–Se alloys in robust bifacial DSSCs. [ABSTRACT FROM AUTHOR]

Storage of liquid electrolyte has been a persistent objective for liquid-state flexible dye-sensitized solar cells (DSSCs). We present here the feasibility of rear-irradiated flexible DSSC comprising of groove stored dye-sensitized TiO 2 on a Ti foil and conductive plastic supported transparent cobalt selenide alloy counter electrode. After being injected into the groove, the liquid electrolyte containing I − /I 3 − redox couples can be well sealed. The flexible cells are optimized by adjusting groove depth and stoichiometry of cobalt selenide electrodes, generating a maximum power conversion efficiency of 7.52% under one sun irradiation. The research demonstrates some new insights on how to improve liquid electrolyte retention and elevate photovoltaic performances of flexible DSSCs. [ABSTRACT FROM AUTHOR]

The exploration of cost-effective and transparent counter electrodes (CEs) is a persistent objective in the development of bifacial dye-sensitized solar cells (DSSCs). Transparent counter electrodes based on binary-alloy metal selenides (M-Se; M=Co, Ni, Cu, Fe, Ru) are now obtained by a mild, solution-based method and employed in efficient bifacial DSSCs. Owing to superior charge-transfer ability for the I−/I3− redox couple, electrocatalytic activity toward I3− reduction, and optical transparency, the bifacial DSSCs with CEs consisting of a metal selenide alloy yield front and rear efficiencies of 8.30 % and 4.63 % for Co0.85Se, 7.85 % and 4.37 % for Ni0.85Se, 6.43 % and 4.24 % for Cu0.50Se, 7.64 % and 5.05 % for FeSe, and 9.22 % and 5.90 % for Ru0.33Se in comparison with 6.18 % and 3.56 % for a cell with an electrode based on pristine platinum, respectively. Moreover, fast activity onset, high multiple start/stop capability, and relatively good stability demonstrate that these new electrodes should find applications in solar panels. [ABSTRACT FROM AUTHOR]

The exploration of cost-effective and transparent counter electrodes (CEs) is a persistent objective in the development of bifacial dye-sensitized solar cells (DSSCs). Transparent counter electrodes based on binary-alloy metal selenides (M-Se; M=Co, Ni, Cu, Fe, Ru) are now obtained by a mild, solution-based method and employed in efficient bifacial DSSCs. Owing to superior charge-transfer ability for the I−/I3− redox couple, electrocatalytic activity toward I3− reduction, and optical transparency, the bifacial DSSCs with CEs consisting of a metal selenide alloy yield front and rear efficiencies of 8.30 % and 4.63 % for Co0.85Se, 7.85 % and 4.37 % for Ni0.85Se, 6.43 % and 4.24 % for Cu0.50Se, 7.64 % and 5.05 % for FeSe, and 9.22 % and 5.90 % for Ru0.33Se in comparison with 6.18 % and 3.56 % for a cell with an electrode based on pristine platinum, respectively. Moreover, fast activity onset, high multiple start/stop capability, and relatively good stability demonstrate that these new electrodes should find applications in solar panels. [ABSTRACT FROM AUTHOR]

Enhancement of power conversion efficiency has been a long-term objective for dye-sensitized solar cells (DSSCs). In the current work, mesoporous TiO 2 anodes are synthesized by a gel-hydrothermal method using polyvinylpyrrolidone (PVP) as a pore-forming agent in order to elevate the dye loading, incident light illumination for dye excitation as well as electron transportation along conducting channels from TiO 2 nanoparticles. In comparison with dense TiO 2 anode, the dye illumination is also significantly enhanced, resulting in an increased photoelectron density on conduction band of TiO 2 . The photovoltaic performances are optimized by adjusting PVP dosage in synthesizing mesoporous TiO 2 anode. An impressive power conversion efficiency of 9.86% is recorded under one sun illumination. The power conversion efficiency is increased by ∼53.8% in comparison with the dense TiO 2 anode based DSSC. The high conversion efficiency in combination with simple preparation demonstrates the potential use of the approach in designing efficient DSSCs. [ABSTRACT FROM AUTHOR]

Exploration of cost–effective counter electrodes (CEs) with simple technique for large–scale synthesis has been a persistent objective for dye–sensitized solar cells (DSSCs). In the current work, binary cobalt–platinum (Co–Pt) alloys are synthesized by a mild solution method and implanted into poly(vinylidene fluoride) (PVDF) for coating cost–effective CEs. Owing to the excellent adhesiveness of PVDF, Co–Pt alloys are solidly attached on conductive glass substrate. The electrical conduction ability and electrochemical behavior of interconnected Co–Pt channels demonstrate the potential use of PVDF–implanted Co–Pt alloy CE in robust DSSCs. The electrochemical properties as well as photovoltaic performances are optimized by adjusting stoichiometric ratios of Co/Pt. An optimal power conversion efficiency of 7.61% is recorded from DSSC employing PVDF–implanted Co 2 Pt alloy CE, which is better than 6.02% from expensive Pt CE or 1.45% from PVDF–implanted Co–CE based DSSC. Relatively stabilities in photocurrent and multiple start/stop cycles are determined for the cell with PVDF–implanted Co–Pt alloy CE. [ABSTRACT FROM AUTHOR]

Abstract: Liquid electrolytes containing redox species have been widely used in dye-sensitized solar cells (DSSCs), whereas the volatility of organic solvents has been a tremendous obstacle for their commercial application. To assemble durable DSSCs, here we report the synthesis of full-ionic liquid electrolyte, in which 1-butyl-3-methylimidazolium nitrate is employed as solvent and 1-methyl-3-propylimidazolium iodide is iodide source. Using the imbibition performance of amphiphilic poly(acrylic acid/gelatin) [poly(AA/GR)] and poly(acrylic acid/cetyltrimethyl ammonium bromide) [poly(AA/CTAB)] matrices, full-ionic liquid electrolytes are imbibed into three-dimensional framework of poly(AA/GR) or poly(AA/CTAB) to form stable gel electrolytes. Room-temperature ionic conductivities as high as 17.82 and 18.44 mS cm−1 are recorded from full-ionic liquid imbibed poly(AA/GR) and poly(AA/CTAB) gel electrolytes, respectively. Promising power conversion efficiencies of 7.19% and 7.15% are determined from their DSSC devices in comparison with 6.55% and 6.12% from traditional acetonitrile-based poly(AA/GR) and poly(AA/CTAB) gel electrolytes, respectively. The new concept along with easy fabrication demonstrates the full-ionic liquid electrolytes to be good alternatives for robust gel electrolytes in quasi-solid-state DSSCs. [Copyright &y& Elsevier]

Dye-sensitized solar cells (DSSCs) have attracted growing interest because of their application in renewable energy technologies in developing modern low-carbon economies. However, the commercial application of DSSCs has been hindered by the high expenses of platinum (Pt) counter electrodes (CEs). Here we use Pt-free binary Co-Ni alloys synthesized by a mild hydrothermal strategy as CE materials in efficient DSSCs. As a result of the rapid charge transfer, good electrical conduction, and reasonable electrocatalysis, the power conversion efficiencies of Co-Ni-based DSSCs are higher than those of Pt-only CEs, and the fabrication expense is markedly reduced. The DSSCs based on a CoNi0.25 alloy CE displays an impressive power conversion efficiency of 8.39 %, fast start-up, multiple start/stop cycling, and good stability under extended irradiation. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) have attracted growing interest because of their application in renewable energy technologies in developing modern low-carbon economies. However, the commercial application of DSSCs has been hindered by the high expenses of platinum (Pt) counter electrodes (CEs). Here we use Pt-free binary Co-Ni alloys synthesized by a mild hydrothermal strategy as CE materials in efficient DSSCs. As a result of the rapid charge transfer, good electrical conduction, and reasonable electrocatalysis, the power conversion efficiencies of Co-Ni-based DSSCs are higher than those of Pt-only CEs, and the fabrication expense is markedly reduced. The DSSCs based on a CoNi0.25 alloy CE displays an impressive power conversion efficiency of 8.39 %, fast start-up, multiple start/stop cycling, and good stability under extended irradiation. [ABSTRACT FROM AUTHOR]