Commercialization Of Dye-sensitized Solar Cells Research Articles

Efficient indoor dye-sensitized solar cells based on TiO2 hollow sphere

The upcoming successful commercialization of dye-sensitized solar cells as is conditioned by the improvement of the device performance and durability. One of promising strategies exploited so far is co-sensitization, which involved the development of the dyes with high light absorption together with high expensive photovoltage redox mediators. Here, we propose a different strategy to improve ambient light harvesting capacity and durability using the three-dimensional hollow sphere architecture of the photoanode, commercial XY1b dye, and common iodide/triiodide redox electrolyte. Under 1000 lux illumination, TiO2 hollow spheres obtained by near-supercritical solvothermal synthesis with tuning shell thickness provided a power conversion efficiency of 25.25%, which is a 56.6% increase comparable to dispersed nanoparticles used in classical dye-sensitized solar cells. Together with the dye loading capacity and light scattering efficiency, the TiO2 hollow spheres improved the long-term stability of the cell under indoor lighting conditions. Thus, even after 720 h of operation, the DSSC continued to provide a stable short-circuit current with a moderate increase, approximately 10% from the initial value.

Experimental and computational investigation of multi-walled carbon nanotubes decorated by Co–Ni–Se@MoSe2 core–shell as a sustainable counter electrode for dye-sensitized solar cells

The development of a highly active, long-lasting, and cost-effective electrocatalyst as an alternative to platinum (Pt) is a vital issue for the commercialization of dye-sensitized solar cells (DSSCs). Herein, Co–Ni–Se@MoSe2 core–shell structures decorated on multi-walled carbon nanotubes (MWCNTs) were synthesized for the first time by the hydrothermal and probe-sonication methods. The electrochemical performance of this composite was examined using electrochemical measurement techniques. The results showed improved properties and better electrochemical activities of the Co–Ni–Se@MoSe2@MWCNTs than Pt and other counter electrodes (CEs) for the triiodide reduction and exhibit good electrochemical stability in iodine-based electrolytes. The power conversion efficiency of DSSCs based on Co–Ni–Se@MoSe2@MWCNTs CE reaches 9.43%, significantly superior to that with Co–Ni–Se@MoSe2 core–shell (8.13%), Pt CE (7.44%), and other CEs. The notable performance is attributed to the synergistic effect between Co–Ni–Se@MoSe2 and MWCNTs. As a result, the transfer of electrons to the active site is promoted, the agglomeration of Co–Ni–Se@MoSe2 is hampered, and more active sites are available. Density functional theory calculations revealed that I2 adsorption on MoSe2 surfaces facilitated the generation of I− ions, which played a critical role in enhancing the reaction efficiency. Therefore, the Co–Ni–Se@MoSe2@MWCNTs composite is a promising candidate for use in high-performance DSSCs.

Insights into the Application of 2D Phosphorene in Dye‐Sensitized Solar Cells

With simpler manufacturing processes and production costs lower than by one‐fifth of those for silicon solar cells, dye‐sensitized solar cells (DSSCs) are among the most promising technologies of third‐generation cells possessing the capability of producing electricity under cloudy conditions and low or artificial light in comparison to other technologies. Although large‐scale commercialization of DSSCs is inhibited by their low power conversion efficiency. To boost the efficiency, several approaches have been implemented, including 2D phosphorene material, which has attracted interest due to its unique characteristics. Since its synthesis in 2014, the use of 2D phosphorene in various optoelectronic devices, including solar cells, has been widely reviewed in the literature. The deficiency in the availability of full reviews on the integration of 2D phosphorene in DSSCs propels this review to focus on research studies relating to the application of 2D phosphorene in DSSCs.

A Review on Liquid Electrolyte Stability Issues for Commercialization of Dye-Sensitized Solar Cells (DSSC)

Dye-sensitized solar cells have been under development for the last three decades but are yet to see the market. This has been attributed to stability issues of the electrolyte in the cell. Electrolytes can be liquid, quasi-solid, or solid. Liquid electrolytes were the first to be developed and, therefore, have been subject to radical revisions in both composition and applicability. They have shown the best power conversion efficiencies but have poor thermal stability. Although quasi-solid and solid-state electrolytes were developed to overcome these stability issues, they too have their limits. The aim of this paper is to explore the development of liquid electrolytes, outlining the current state of the technology and considering their potential in the photovoltaic market.

Design of an amorphous ZnWSe2 alloy-based counter electrode for highly efficient dye-sensitized solar cells

Amorphous ZnWSe2 alloy-based counter electrodes grown by magnetron sputtering technique can indeed possess superior optoelectronic properties, resulting in a substantial efficiency of 8.27% and prolonged photostability.

One-pot hydrothermal in situ growth of In4SnS8@MoS2@CNTs as efficient Pt-free counter electrodes for dye-sensitized solar cells

Developing a synthesis method for large-scale preparation of efficient and economical non noble metal counter electrode (CE) electrocatalytic materials with good catalytic ability and stability is an ideal choice for the commercialization of dye-sensitized solar cells (DSSCs). In this paper, a novel micro-nanostructured composite of CE was prepared by fixing the In4SnS8 and MoS2 on carbon nanotubes (CNTs) and using a one-step hydrothermal strategy. The devices based on the In4SnS8@MoS2@CNTs composite CE performs high power conversion efficiency of 8.72%, far more than that of the device with the control ones (7.57%). The In4SnS8@MoS2 composite were homogeneously distributed on the CNTs surface to form a new In4SnS8@MoS2@CNTs composite network heterojunction. This distinctive porous structure can provide greater contact area and electronic transmission channel to ensure fast charge transport of electrolyte. The prefect electrochemical properties of the In4SnS8@MoS2@CNTs CE for the I−/I3− electrolyte also have been demonstrated by a series of electrochemical tests. As a result, it can be considered that the In4SnS8@MoS2@CNTs will replace the Pt CE and has broad application prospects in DSSCs.

Molecular Weight Effects of Biscarbazole-Based Hole Transport Polymers on the Performance of Solid-State Dye-Sensitized Solar Cells

The leakage and volatilization of liquid electrolytes limit the commercialization of dye-sensitized solar cells (DSCs). As solid-state (ss) hole-transporting materials, free from leakage and volatilization, biscarbazole-based polymers with different molecular weights (PBCzA-H (21,200 g/mol) and PBCzA-L (2450 g/mol)) were applied in combination with additives to produce ssDSCs. An ssDSC with PBCzA-H showed a better short-circuit current (Jsc), open-circuit voltage (Voc), and fill factor (FF) than a device with PBCzA-L, resulting in 38% higher conversion efficiency. Compared to the PBCzA-L, the PBCzA-H with a higher molecular weight showed faster hole mobility and larger conductivity, leading to elevations in Jsc via rapid hole transport, Voc via rapid hole extraction, and FF via lowered series and elevated shunt resistances. Thus, it is believed that PBCzA-H is a useful candidate for replacing liquid electrolytes.

MFe2O4(M=Co, Mn)@MG as an Efficient Counter Electrode for Dye-sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) are considered as low-cost and eco-friendly alternatives for conventional silicon solar cells. Dye-sensitized metal oxide photoelectrode, electrolyte and counter electrode (CE) are the three major components of a DSSC. An ideal CE material should have superior electrocatalytic activity and distinguished conductivity, excellent chemical stability, and low cost. Noble metal Pt CE has an efficient capacity for collecting electrons from external circuits and facilitating the catalytic reduction of I3 - to I-. However, its high cost seriously restricts mass production and commercialization of DSSCs. Therefore, carbon composite materials, inorganic compounds, conducting polymers and their derivatives have been widely explored as CEs in DSSCs.Recently, multiple transition metals and their derivative have been investigated as the CE materials for DSSCs. Theoretically, binary or ternary transition metals display intrinsic electrocatalytic activity toward the reduction of I3 - with rapid charge-transfer ability and cost-effectiveness. Thus, transition-metal ferric acid MFe2O4 (M=Mn, Co) composited with modified graphene (MG) is a novel strategy to achieve an advanced CE material with remarkable electrochemical performance. As we all know, graphene microstructure has a lamellar structure. Through a process of catalytic reduction, a curly structure modified graphene not only displays a large specific surface area to facilitate charge transfer and promote catalytic performance during photoelectric conversion, but also the conjugated structure with continuous sp2 hybridized carbon centers can induce electronic mobility.Ferrite is a unique hierarchical nanostructure material mainly composed of transition metal (i.e., Co, Mn, Ni), iron (Fe), and oxygen (O). Transition-metal ions M2+ (M2+ =Mn2+, Co2+) have excellent electrocatalytic capability, and active Fe atoms can synergize with carbon atoms in graphene to significantly improve catalytic activity. This work offers a strategy to apply MFe2O4(M=Mn, Co)@MG composite as the CE of DSSCs to optimize catalytic sites and improve catalytic performance. The device based on the CoFe2O4@MG CE achieves a PCE of 7.78%, and the device based on MnFe2O4@MG CE has a PCE of 5.55%. Moreover, the device was prepared by a simple process with an excellent stability in the air atmosphere without encapsulation (maintaining 93.3% of an initial PCE after 30 days), which can facilitate large-scale production in the future.

Photoanodes for Aqueous Solar Cells: Exploring Additives and Formulations Starting from a Commercial TiO2 Paste.

Whereas the commercialization of dye-sensitized solar cells (DSSCs) is finally proceeding taking advantage of their low cost and tunable optical features, such as colour and transparency for both indoor and building-integrated applications, the corresponding aqueous counterpart is still at its infancy. As the TiO2 electrode is a fundamental component for hybrid solar cells, this work investigates the effect of different molecular (α-terpineol, propylene carbonate) and polymeric (polyethylene oxide, polyethylene glycol, carboxymethyl cellulose and xanthan gum) additives that can be introduced into a commercial TiO2 paste for for screen-printing (or doctor blade). Among all, the addition of polyethylene glycol leads to the best cell performances, with markedly increased short-circuit current density (+18 %) and power conversion efficiency (+48 %) with respect to the pristine (commercial) counterpart. When further explored at different concentration levels, electrodes fabricated from polyethylene glycol-based pastes show different morphologies, thicknesses and performances, which are investigated through (photo)electrochemical, structural, physical-chemical and microscopic techniques.

Enhanced electrochemical and photovoltaic performance for MoO3 nanorods at different calcination temperature based counter electrode in Pt-free dye-sensitized solar cells applications

Owing to increase in energy demands and depletion in fossil fuels, solar energy conversion is the reliable and sustainable one for future. Among the solar energy conversion techniques, dye-sensitized solar cells (DSSC) have received much attention due to their ease of fabrication, cost-effectiveness, reliable and high proficiency in converting solar energy. The commercialization of DSSC is still hindered by usage of expensive materials like platinum counter electrodes. Therefore, researchers are focusing on developing low-cost and earth abundant alternatives. The present work involves hydrothermal synthesis of molybdenum trioxide (MoO3) at various temperature ranges such as 400, 500, 600 and 700 °C and several other characterizations through various analytical techniques. On increasing the temperature range, the MoO3 forms nanorod like structure. The synthesized materials are employed as counter electrode in DSSC, showed enhanced power conversion efficiency (PCE) on increasing the calcination temperature range. The maximum PCE of 4.13% is obtained for MoO3 calcined at 600 °C, which is highly comparable with the high cost platinum CE based DSSC.

Reaching stability at DSSCs with new type gel electrolytes

Stability is a significant problem for dye-sensitized solar cells (DSSCs) and if the problem cannot be surmounted, commercialization of DSSCs will not be possible. This work aims to show and solve the main reason for DSSCs’ stability problem. It is known that natural dyes are degradable; thus, a natural dye was used as a sensitizer to obtain the worst conditions for preparing DSSCs. The produced DSSCs were tested for 3 600 h and stability was achieved with the use of newly produced gels. The six newly produced gels were synthesized and seven DSSCs were produced. One of the DSSCs was prepared with a standard liquid electrolyte while the others were prepared with a liquid electrolyte adsorbed into poly(2-acrylamide-2-methylpropane sulfonic acid/itaconic acid/N,N'-methylenebisacrylamide) (poly(AMPS-co-IA)) hydrogel and its fluorine, bromine, chlorine, and aniline doped derivatives. The DSSCs prepared with the hydrogel based-electrolytes showed stable and improved electrical characteristics for 3 600 h while the DSSC prepared with the liquid electrolyte’s performance got weaker from day to day and was wholly finished at 3 240 h.

Molecular Design Strategy toward Robust Organic Dyes in Thin-Film Photoanodes

The photo-, thermal, and water stability of dyes is indispensable for the commercialization of dye-sensitized solar cells, necessitating the development of systematic molecular design strategies to...

Formation of CoTe2 embedded in nitrogen-doped carbon nanotubes-grafted polyhedrons with boosted electrocatalytic properties in dye-sensitized solar cells

Developing high active and earth-abundant electrocatalysts is a challenge for commercialization of dye-sensitized solar cells (DSSCs). Herein, a designed synthesis of CoTe2 nanoparticles embedded in nitrogen-doped carbon nanotubes-grafted polyhedron (CoTe2@NCNTs) using zeolitic imidazolate framework-67 (ZIF-67) as template is reported. Benefiting from the high surface area induced by the in situ growth of CNTs and the synergistic effect between CoTe2 and the N-doped nanostructured carbon, CoTe2@NCNTs hybrids exhibit remarkable catalytic activity toward the reduction of I3− ions. When employed as counter electrode (CE) of DSSCs, CoTe2@NCNTs hybrids deliver overwhelming power conversion efficiency (PCE) of 9.02%, possessing ~12% improvement compared with the Pt CE (8.03%). This study provides an emerging substitute for traditional Pt CE and a strategy to synthesize efficient electrocatalysts via rational surface engineering.

MoS2 coated CoS2 nanocomposites as counter electrodes in Pt-free dye-sensitized solar cells.

Expensive Pt counter electrodes remain an obstacle for the commercialization of dye-sensitized solar cells (DSSCs). Therefore, research focusing on low-cost alternative counter electrode materials has been considered important for their commercialization. Here, the fabrication of dye-sensitized solar cells has been performed utilizing CoS2 and MoS2 coated CoS2 nanocomposite materials as the counter electrode, which are synthesized via a hydrothermal route involving low-cost precursor materials. The experimental results obtained from XRD, XPS, EDX, SEM, TEM, and Raman etc. have confirmed the successful formation of CoS2 and MoS2 coated CoS2 nanocomposites. The electrochemical characterization of these materials is performed, which suggests that the electrocatalytic activity towards the liquid iodine electrolyte of these materials is as good as that of the conventional Pt counter electrodes. So, dye-sensitized solar cell devices are fabricated by interpolating a (cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(ii)) dye-loaded TiO2 photoanode and CoS2, MoS2 coated CoS2 and Pt counter electrodes using iodine/iodide as a liquid electrolyte. The devices fabricated with CoS2 counter electrodes have shown an open circuit voltage of 790 mV, a short circuit current of 11.9 mA cm-2, a fill factor of 0.54, and a power conversion efficiency of 6%. On the other hand, the device based on a Pt counter electrode has shown an open circuit voltage of 773 mV, a short circuit current of 13.4 mA cm-2, a fill factor of 0.54, and a power conversion efficiency of 6.6%. In addition, MoS2 coated with a CoS2 counter electrode has shown the best performance with an open circuit voltage of 763 mV, a short circuit current of 20.1 mA cm-2, a fill factor of 0.42, and a power conversion efficiency of 7.6%.

Efficient and Stable Dye-Sensitized Solar Cells Based on a Tetradentate Copper(II/I) Redox Mediator.

The identification of an efficient and stable redox mediator is of paramount importance for commercialization of dye-sensitized solar cells (DSCs). Herein, we report a new class of copper complexes containing diamine-dipyridine tetradentate ligands (L1 = N, N'-dibenzyl- N, N'-bis(pyridin-2-ylmethyl)ethylenediamine; L2 = N, N'-dibenzyl- N, N'-bis(6-methylpyridin-2-ylmethyl)ethylenediamine) as redox mediators in DSCs. Devices constructed with [Cu(L2)]2+/+ redox couple afford an impressive power conversion efficiency (PCE) of 9.2% measured under simulated one sun irradiation (100 mW cm-2, AM 1.5G), which is among the top efficiencies reported thus far for DSCs with copper complex-based redox mediators. Remarkably, the excellent air, photo, and electrochemical stability of the [Cu(L2)]2+/+ complexes renders an outstanding long-term stability of the whole DSC device, maintaining ∼90% of the initial efficiency over 500 h under continuous full sun irradiation. This work unfolds a new platform for developing highly efficient and stable redox mediators for large-scale application of DSCs.

Alloyed PtNi counter electrodes for high-performance dye-sensitized solar cell applications

The preferred Pt counter electrode (CE) has been an economic burden for commercialization of dye-sensitized solar cells (DSSCs). To address this issue, we present here the fabrication of a series of hollow PtNi alloy CEs tailored with ZnO micro/nanostructures. The preliminary results demonstrate that alloyed PtNi electrode displays markedly increased performances in transporting charges, catalyzing redox electrolyte, and remaining persistent stability under long-term operation in comparison with standard Pt electrode. The optimized liquid-junction DSSC device from PtNi1.07 CE yields a maximal power conversion efficiency of 9.08%, suggesting a 43% enhancement compared with 6.35% for Pt based photovoltaics.

Metal-Organic Framework Derived CoNi@CNTs Embedded Carbon Nanocages for Efficient Dye-Sensitized Solar Cells

The commercialization of dye-sensitized solar cells (DSSCs) has been severely hindered by high cost and scarcity of Pt as counter electrode (CE). Up to date, the design of low-cost Pt-free CE materials with an ideal combination of high electrical conductivity, excellent catalytic activity and satisfactory long-term electrochemical stability still poses challenges to researchers. In this work, we have developed novel CoNi alloy@carbon nanotubes embedded carbon nanocages (CoNi@CNTs-C) as the CE of DSSCs for the first time, by applying Co/Ni bimetallic metal organic framework (MOF) as the template. The power conversion efficiency (PCE) of DSSCs can be maximized by simply optimizing the ratio of Ni2+/Co2+ precursor ratio during the synthesis. As a result, the DSSC based on CoNi@CNTs-C-200 CE with a Co/Ni atomic ratio of 9:1 exhibits a remarkable PCE of 9.04%, showing a ∼15% enhancement compared to that of Pt CE (7.88%). Notably, the CoNi@CNTs-C-200 CE also demonstrates excellent long-term electrochemical stability over 300 cyclic voltammetry cycles, which is much superior to that of conventional Pt CE. Thus, the CoNi@CNTs-C demonstrates a great potential as a low-cost, stable and efficient CE material for next-generation DSSCs.

Long-term Stability of Conducting Polymers in Iodine/iodide Electrolytes: Beyond Conventional Platinum Catalysts

One of the primary obstacles to the commercialization of dye-sensitized solar cells (DSSCs) is the improvement of their long-term stability. Here, we report greatly improved long-term stability of DSSCs, which have PEDOT:FTS polymer as a counter electrode. DSSCs with this PEDOT:FTS film demonstrate slightly lower power conversion efficiency of 8.1% under standard conditions (AM 1.5G, 100mWcm−2) compared to the ∼9.1% efficiency of Pt, using an electrolyte with iodine/iodide, which is the most popular redox shuttle. However, we demonstrate that this conducting polymer counter electrode facilitates the fabrication of solar cells with greatly improved long-term stability compared to Pt-based ones after exposure to electrolyte soaking conditions. Various electrochemical analyses were performed to evaluate the enhanced durability of PEDOT:FTS polymer in the highly corrosive iodine/iodide electrolyte under a continuous redox reaction condition.

Tri-iodide reduction activity of ultra-small size PtFe nanoparticles supported nitrogen-doped graphene as counter electrode for dye-sensitized solar cell

Efficient and cost effective counter electrode (CE) is pre-requisite for the commercialization of dye-sensitized solar cell (DSSC). Present work investigates ultra small size platinum-iron alloy nanoparticles dispersed over nitrogen-doped graphene (PtFe/NG) as an effective counter electrode for DSSC. Hereby we achieve low loading of Pt by alloying with Fe accompanied by superior electrocatalytic activity towards the iodide-triiodide (I−/I3−) mechanism. Enhancement in electrocatalytic performance of PtFe/NG has been shown by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization analysis. PtFe/NG counter electrode exhibits higher power conversion efficiency (∼6.12%) with lower charge transfer resistance, which helps in faster diffusion of I−/I3− ions as compared to NG and Pt/NG counter electrodes. The increased electrocatalytic activity of PtFe/NG is due to the collective effect of intrinsic electronic effects by alloying, uniform dispersion of small PtFe alloy nanoparticles over nitrogen doped graphene, and additional catalytic sites offered by nitrogen-doped graphene.

Counter electrodes from polymorphic platinum-nickel hollow alloys for high-efficiency dye-sensitized solar cells

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(NO3)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.