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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]

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]

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]

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 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]

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]

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]

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]

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]

Abstract: With an aim of enhancing the light-to-electric power conversion efficiency of dye-sensitized solar cell (DSSC), here we synthesize PtRu nanofiber alloys using a low-temperature hydrothermal technique which are employed as counter electrodes (CEs) for DSSCs. Owing to the good electrical conduction and electrocatalysis, light-to-electric power conversion efficiencies of PtRu-based DSSCs have been elevated in comparison with that of Pt CE based DSSC. The DSSC employing PtRu3 alloy CE gives a power conversion efficiency of 6.80% in comparison with 6.17% from Pt-based DSSC. The reasonable conversion efficiency, simple preparation, and scalability demonstrate the potential use of PtRu alloys in efficient DSSCs. [Copyright &y& Elsevier]

Highlights: [•] PANi-SWCNT complexes are synthesized by a reflux method for rapid charge-transfer. [•] (PANi−SWCNT/GO)n multilayer CEs are fabricated by a self-assembly technique. [•] The charge-transfer ability toward iodide reduction is significantly enhanced. [•] A conversion efficiency of 6.88% is obtained in its DSSC. [•] The strategy provides new opportunities for efficient DSSC assembly. [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate here the growth of spiny polyaniline (PANi) nanofibers on Pt layer through a stepwise control of current density and employment as CE in DSSC. The superiority of this new nanostructure is evaluated by electrochemical characterizations. The resulting PANi nanostructures give an enhanced electrocatalytic activity toward iodides. Careful examination of data and characterizations indicates that the promising properties are impressive to fulfill the task of CEs. A promising power conversion efficiency of 7.66% is obtained in Pt/spiny PANi nanofiber CE in comparison with 5.89% from Pt-only CE and 6.30% from traditional PANi nanofiber CE. This strategy provides new opportunities for fabricating highly efficient DSSCs. [Copyright &y& Elsevier]

Highlights: [•] (GO/PANi)n multilayer counter electrodes are fabricated by a self-assembly technique. [•] The charge-transfer ability toward iodide reduction is significantly enhanced. [•] A conversion efficiency of 7.41% is obtained in its DSSC in comparison with that of PANi-only. [•] The strategy provides new opportunities for efficient DSSC assembly. [Copyright &y& Elsevier]

Abstract Developing efficient and cost-effective counter electrodes (CEs) to catalyze triiodide reduction reaction is a persistent objective for high-performance dye-sensitized solar cells (DSSCs). One promising solution is to design electron-enriched electrode materials by combining conductive polymers with alloys. In this work, ternary hybrid PtM@polyaniline (M = Ni, FeNi) CEs are synthesized by one-step replacement reaction and in-situ polymerization reaction. When assembling into liquid-junction DSSCs, the power conversion efficiencies of 8.52% and 8.39% for the devices tailored with PtNi@polyaniline and PtFeNi@polyaniline CEs can be obtained. The experimental results demonstrate that the enhanced photovoltaic performances are mainly attributed to matching work function and high electrocatalytic activity of these well-designed hybrid CEs. Arising from the competitive reactions between transition metal and I 2 /I 3 − species, the dissolution reaction of Pt in liquid electrolyte is restricted and therefore the long-term stability of corresponding devices are significantly enhanced. Graphical abstract Image 1 Highlights • Ternary hybrid PtM@PANi CEs are prepared by one-step method. • Ternary hybrid PtM@PANi CEs are used for DSSC applications. • The hybrid CEs present matching work functions and enhanced catalytic activities. • The device yields a maximized PCE of 8.52% under one sun illumination. [ABSTRACT FROM AUTHOR]

The preferred platinum counter electrode (CE) has been a burden for commercialization of dye-sensitized solar cell (DSSC) due to high expense and chemical corrosion by liquid electrolyte. In the current study, we have successfully realized the multistep deposition of platinum alloy CEs including PtNi, PtFe, and PtCo for liquid-junction DSSC applications. The preliminary results demonstrate that the enhanced electrochemical activities are attributable to high charge-transfer ability and matching work functions of the PtM (M = Ni, Fe, Co) alloy CEs to redox potential of I − /I 3 − electrolyte. The resultant DSSCs yield impressive power conversion efficiencies of 8.65%, 7.48%, and 7.08% with PtNi, PtFe, and PtCo CEs, respectively. On behalf of the competitive reactions between transition metals with liquid electrolyte, the PtM alloy CEs display enhanced long-term stability. [ABSTRACT FROM AUTHOR]

The practical commercialization of dye-sensitized solar cells (DSSCs) requires persistent exploration of cost-effective counter electrodes (CEs). Aiming at increasing the active sites and accelerating charge transfer of a CE electrocatalyst, cobalt sulfide decorated aniline complexes are synthesized by a reflux technique and subsequently in-situ polymerized for Pt-free polyaniline-cobalt sulfide (PANi-CoS) electrocatalysts in liquid-junction DSSCs. The preliminary results suggest that an enhanced electrocatalytic activity for I 3 − reduction is ascribed to the fast electron-transfer ability of PANi and the high catalytic activity of CoS. The optimized DSSC device based on PANi-7 wt% CoS yields an impressive power conversion efficiency up to 8.55% under an illumination of air mass 1.5 global simulated solar light, which is much higher than 5.65% and 5.79% for the solar cells with pure PANi and pristine Pt CEs, respectively. [ABSTRACT FROM AUTHOR]

Understanding the electrocatalytic behaviours of counter electrode (CE) electrocatalysts favors to tune the sluggish triiodide (I 3 − ) reduction kinetics and to compare their catalytic activities. We present here the experimental realization of cost-effective CE electrocatalysts from urchin-like NiM (M = Pt, Ru, Pd) for studying the profounding charge transfer processes without sacrificing photovoltaic performances of DSSCs. Our focus is placed on the systematic studies of catalytic activities along with modeling of I 3 − reduction reaction rate constant, extracting k = 4π Dr a N B for zero-dimensional electrocatalysts. The DSSCs yield conversion efficiencies of 9.08%, 7.74%, and 6.86% with NiPt, NiRu, and NiPd CEs, respectively. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its merits on clean, cost-effectiveness, relatively high efficiency, and easy fabrication. However, the reduction of fabrication cost without sacrifice of power conversion efficiencies of the DSSCs is a golden rule for their commercialization. Here we design a new binary ruthenium selenide (Ru–Se) alloy counter electrodes (CEs) by a low-temperature hydrothermal reduction method. The electrochemical behaviors are evaluated by cyclic voltammogram, electrochemical impedance, and Tafel measurements, giving an optimized Ru/Se molar ratio of 1:1. The DSSC device with RuSe alloy CE achieves a power conversion efficiency of 7.15%, which is higher than 5.79% from Pt-only CE based DSSC. The new concept, easy process along with promising results provide a new approach for reducing cost but enhancing photovoltaic performances of DSSCs. [ABSTRACT FROM AUTHOR]

Abstract: An inexpensive microporous polyaniline (PANI) is used as a substitute for platinum to construct the counter electrode in dye-sensitized solar cells (DSSCs). The PANI counter electrode with microporosity and a size diameter of about 100nm possesses lower charge-transfer resistance and higher electrocatalytic activity for the redox reaction than Pt electrode does. The overall energy conversion efficiency of the DSSC with PANI counter electrode reaches 7.15%, which is higher than that of the DSSC with Pt counter electrode. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow PANI electrode to be a credible alternative for DSSCs. [Copyright &y& Elsevier]

Graphical abstract Co/Se and Ni/Se nanocomposite films deposited on FTO glasses via magnetron sputtering are used as counter electrodes in dye-sensitized solar cells, yielding a maximized power conversion efficiency of 6.43%. Highlights: • Co/Se and Ni/Se nano-films are prepared by magnetron sputtering method. • The as-prepared films are employed as CEs for DSSCs. • The DSSC with Co/Se CE delivers a PCE of 6.43%. Abstract Dye-sensitized solar cells are promising solutions to energy and environmental problems. By addressing the high cost of preferred platinum counter electrode, Co/Se and Ni/Se nanocomposite counter electrodes are prepared by magnetron sputtering targets onto fluorine-doped tin oxide glass for dye-sensitized solar cell applications. The binary nanocomposite counter electrodes exhibit superior electrocatalytic activity toward I 3 − reduction compared to pure Ni, Se and Co electrodes. In particular, the dye-sensitized solar cell based on Co/Se counter electrode achieves a power conversion efficiency of 6.43%, which is much higher than 0.87%, 2.91%, 3.77% and 5.23% for Ni, Se, Co and Ni/Se solar cells, respectively. The preliminary results demonstrate it is a promising strategy to prepare robust counter electrodes by magnetron sputtering technique for dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

Bifacial dye-sensitized solar cells (DSSCs) are regarded as promising photovoltaics to harvest solar energy from both front and rear sides because of their significantly increased total power outputs. Transparent counter electrodes (CEs) with cost-effectiveness and high electrocatalytic activity are crucial to make these high-performance bifacial devices. Herein, a category of transparent CEs from ternary alloys [(CoM) 0.85 Se, M = Ni, Ru, Fe] are synthesized by a mild solution method. Upon careful optimization on optical behaviors, electrocatalytic activity and photovoltaic performances, the bifacial DSSCs with (CoNi) 0.85 Se, (CoRu) 0.85 Se, (CoFe) 0.85 Se CEs achieve front power conversion efficiencies of 9.14%, 8.09%, 7.58% and rear efficiencies of 3.86%, 3.31%, 3.51% in comparison with 6.72% and 3.16% for state-of-the-art Pt CE based solar cell, respectively. Moreover, these bifacial DSSCs devices display high multiple on/off capability and relatively good stability. [ABSTRACT FROM AUTHOR]

Exploration of cost-effective and transparent counter electrodes (CEs) with high electrocatalytic activity has been a persistent objective of bifacial dye-sensitized solar cells (DSSCs) development. Here, with an aim of accelerating charge transfer and increasing the active sites of a transparent CE, molybdenum sulfide (MoS 2 ) decorated aniline complexes are synthesized by a reflux technique and subsequently in-situ polymerized for transparent polyaniline (PANi)-MoS 2 complex CEs for efficient bifacial DSSCs. The preliminary results indicate that the electrocatalytic activity toward I 3 − reduction of PANi-MoS 2 complex CE is dramatically enhanced due to the fast charge transfer between PANi (N atoms) and MoS 2 (Mo atoms) by the metal (dπ)-nitrogen (pπ) antibonding interaction. Owing to the high optical transparency, electrocatalytic reduction toward I 3 − species, superior charge-transfer ability for I − /I 3 − redox couples, the bifacial DSSCs based on PANi-6 wt‰ MoS 2 complexes CE yield a maximum power conversion efficiency of 7.99% from front irradiation, 3.40% from rear irradiation and 9.71% from both irradiation, which are higher than front, rear and both efficiencies of 6.37%, 1.78% and 7.50% for DSSC employing PANi CE, respectively. The high optical transparency and electrocatalytic activity along with simple preparation, relatively low cost and scalability demonstrate the potential use of PANi-MoS 2 complex as a robust CE in bifacial DSSCs. [ABSTRACT FROM AUTHOR]

Pursuit of cost-effective counter electrodes (CEs) with no sacrifice of photovoltaic performances is a persistent objective for dye-sensitized solar cells (DSSCs). We launch here the experimental realization of molybdenum selenide (Mo–Se) binary nanosheet CEs by a mild solution method. Due to high optical transparency, the bifacial DSSCs from cost-effective Mo–Se alloy CEs can realize electricity generation from either front or rear side. Particularly, the resultant Mo–Se alloy CEs show superior catalytic activity and charge-transfer ability toward I − / I 3 − redox electrolyte. The maximum front and rear efficiencies of 8.05% and 5.92% are recorded under simulated air mass 1.5 global irradiation, respectively. The impressive efficiency along with fast start-up, multiple start capability, and simple preparation highlights the potential application of the cost-effective and transparent Mo–Se alloy CE in robust bifacial DSSCs. [ABSTRACT FROM AUTHOR]

A transparent catalytic counter electrode (CE) with excellent properties plays an important role in the performance improvement of bifacial dye-sensitized solar cells (Bi-DSSCs). In this work, pyrrole is combined with molybdenum sulfide (MoS 2) by a refluxing technology and subsequently polymerized in situ to construct polypyrrole (PPy)-MoS 2 CEs with high transparency. And compared with the original PPy CE, the PPy-MoS 2 CE shows higher electrocatalytic activity for triiodide reduction. A superior power conversion efficiency of 9.48% under both-side irradiation is obtained for the Bi-DSSCs assembled with PPy-4 wt‰ MoS 2 complex CE, compared to 7.36% bifacial efficiency for PPy-CE based solar cell. [Display omitted] • Pyrrole-MoS 2 complexes are synthesized by a reflux process. • PPy-MoS 2 complexes are used as transparent and cost-effective CEs for bifacial DSSCs. • The incident light from rear side can compensate for the light from anode. • The DSSC assembled with PPy-MoS 2 complex CE has a high bifacial efficiency of 9.48%. [ABSTRACT FROM AUTHOR]