Generation Dye-sensitized Solar Cells Research Articles

Theoretical exploration of a di-carbazole based dye for 3rd generation dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are known for their large potential in green, efficient and cost-effective solar energy technology. Therefore, investigating the solar-to-electricity conversion mechanism of photosensitizers in DSSCs can open up a new way for highly effective and stable solar cell devices. In this study, we used different molecular design strategies to develop various D-π-A photosensitizers based on dicarbazole. These approaches involved changing the positions of auxiliary acceptors and π-spacers as well as introducing new π-spacer units. To calculate the physical and electronic properties of these sensitizers, density functional theory (DFT) and time dependent density functional theory (TDDFT) were adopted. FMO analysis showed a significant charge transfer from the donor through the spacer to the acceptor which was also supported by DOS analysis. Energy gap of designed dyes have less than experimental Cz dye. NBO analysis has carried out the bond strength assessment and the studied molecule’s central nitrogen atoms related MOs. All the designed dyes exhibited good nonlinear optical (NLO) properties with maximum linear polarizability 〈α〉 amplitudes higher than first (βtotal) compared to the reference chromophore. Photovoltaic efficiency has been evaluated to electronic (Egap), open circuit voltage (VOC), short circuit current density (JSC), electron injection ability (∆Ginj), electron regeneration (∆Greg) and light harvesting efficiency.

Multi-component eutectic salts to enhance the conductivity of solvent-free ionic liquid electrolytes for dye-sensitized solar cells

Ionic liquids (ILs) possess intrinsic nonvolatility, low flammability, high ionic conductivity, high thermal and chemical stability, rendering themselves as excellent candidates for next generation dye-sensitized solar cells (DSSCs). Further improving the ionic conductivity of ionic liquid electrolytes is critical to the performance enhancement of DSSCs. Here, multi-component eutectic salts by mixing four ILs are proposed to achieve higher ionic conductivity compared to the individual one. In addition, the effect of mixing strategy on the eutectic salts was systematically investigated by diverse structural, thermal, electrochemical and photovoltaic characterization in detailed. It revealed that mixing strategy could not only tune the solid-state property of individual ILs to liquid-state eutectic salts, but also greatly improve the ionic conductivity of final multi-component eutectic salts. Thus, based on the multi-component eutectic salt, a power conversion efficiency (PCE) of 4.81% could be obtained by the resultant device. Moreover, the DSSCs with multi-component eutectic salt also display better stability than the referenced device with volatile organic solvent. The mixing eutectic salts offer us a feasible strategy to design high ionic conductive electrolytes for high performance dye-sensitized solar cells.

Promising sensitizers for dye sensitized solar cells: A comparison of Ru(II) with other earth's scarce and abundant metal polypyridine complexes

AbstractThere has recently been a growing interest in dye sensitized solar cells (DSSCs) based on ruthenium metal, but due to the scarcity and high price of ruthenium, design of better and cheaper light adsorbent dyes based on more abundant metal ions is one of the key issues for future development of the DSSCs. Using density functional theory (DFT) and time‐dependent DFT we have studied the properties of new and abundant metal ion‐based polypyridyl dyes for p‐type DSSCs and compared with ruthenium and other scarce metal ions. Molecular geometries, electronic structures, and optical absorption spectra have been calculated using an implicit solvent corresponding to acetonitrile. The calculated fair light harvesting efficiency, high hole injection efficiency and Gibbs free energy for the hole injection and longer excited state lifetime (important for reflecting the efficiency of solar cells) for the new abundant metal ions (V3+ and Cr2+) based dyes could provide promising sensitizers for efficient next generation DSSC's for p‐SC.

Strategies, Technologies and Novel Components for the Architectural Integration of Photovoltaics

The research deals with the architectural integration of photovoltaics (PV) for the energy retrofit of the existing building stock and the construction of new Zero Energy Buildings. The objective is the study and subsequent definition of strategies, technologies and novel components for the building envelope integrating photovoltaics, with particular attention towards new generation solar technologies. The work also focuses on the energy optimization and performance analysis of a novel BIPV component for sustainable translucent building envelopes, namely a panel made of glass blocks integrated with 3 rd generation dye-sensitized solar cells.

Strategies, Technologies and Novel Components for the Architectural Integration of Photovoltaics

The research deals with the architectural integration of photovoltaics (PV) for the energy retrofit of the existing building stock and the construction of new Zero Energy Buildings. The objective is the study and subsequent definition of strategies, technologies and novel components for the building envelope integrating photovoltaics, with particular attention towards new generation solar technologies. The work also focuses on the energy optimization and performance analysis of a novel BIPV component for sustainable translucent building envelopes, namely a panel made of glass blocks integrated with 3rd generation dye-sensitized solar cells.

Composite multi-functional over layer: A novel design to improve the photovoltaic performance of DSSC

Light scattering in dye-sensitized solar cell (DSSC) plays a vital role in extending the traveling distance by confining light propagation within the photoanode and also promotes interaction of incident photons with the dye molecules. A novel strategy was adopted to improve the performance of DSSC with better absorption of solar spectrum both in the visible as well as near IR regions. A double layer photoanode structure with TiO2 nanoparticles (P25) as main layer and composite of titanium nanotubes (TNTs) and P25 as over-layer was introduced. Three different compositions of TNT/P25 were investigated, and finally an optimized composition with excellent performance was prepared. Performance of cells having composite over-layer was compared with the cells having TNT and conventional bigger particles (G2) over-layers. Composite over-layer structure of 75/25-TNT/P25 showed best photovoltaic performance of 8.52% with Jsc of 16.49mA/cm2, which is 7.30% higher than the cells having G2 over-layer and 4.9% higher than the cells having pure TNT over-layer. Different characterization analysis proved that DSSC with optimized composite over-layer structure has significant advantages of better dye adsorption, large surface area, better photo-electron generation, superior electron recombination restraint characteristics, better conductive behavior, better light scattering, and long electron lifetime. Composite over-layer structure is a promising and innovative approach for further improving the efficiency of DSSC and this will be a concrete fundamental background toward the development of the applications of the next generation dye-sensitized solar cells.

Hydrothermal synthesis of TiO2 nanotubes and their application as an over-layer for dye-sensitized solar cells

Different nanostructures of TiO2 play an important role in the kinetics of dye sensitized solar cells (DSSC) and affect the overall light harvesting efficiency of the cells. This article describes that the one dimensional nanostructure of TiO2 (nanotubes) can increase the light scattering effect, light harvesting effect and electron transport in the DSSC to improve its performance. Pure anatase TiO2 nanotubes were synthesized by a hydrothermal method using commercial material (P25) due to which the manufacturing cost of the DSSC was enormously reduced. To enhance the power conversion efficiency of the DSSC, a new type of double layered photoanode was prepared and optimized by using TiO2 nanoparticles as the main layer and TiO2 nanotubes (TNT) as the over-layer. These prepared cells were analysed by optical, photovoltaic and electrochemical measurement systems. The cells having the TNT over-layer showed longer electron life time, higher BET surface area and pore volume and 40% improved light harvesting efficiency. This new and optimized structure will be concrete fundamental background towards the development of the applications of next generation dye-sensitized solar cells.

Novel nanostructures for next generation dye-sensitized solar cells

Herein, we review our latest advancements in nanostructured photoanodes for next generation photovoltaics in general and dye-sensitized solar cells in particular. Bottom-up self-assembly techniques are developed to fabricate large-area 3D nanostructures that enable enhanced charge extraction and light harvesting through optical scattering or photonic crystal effects to improve photocurrent, photovoltage and fill factor. Using generalized techniques to fabricate specialized nanostructures enables specific optoelectronic and physical characteristics like conduction, charge extraction, injection, recombination and light harvesting but also helps improve mechanical flexibility and long-term stability in low cost materials.

Synthesis of copolymer electrolytes based on polysiloxane and their high temperature durability analysis for solvent-free dye-sensitized solar cells

The present work develops a new type of solvent-free copolymer electrolyte based on polysiloxane for dye-sensitized solar cells (DSSCs). The electrolyte is characterized by conductivity measurements, hydrogen-1 nuclear magnetic resonance spectroscopy, rheology, and DSSC performance. Repeated units of the ethylene oxide on methylhydrosiloxane show plasticizing effects and enhanced durability of the DSSCs. DSSC employing the polysiloxane electrolytes show no energy conversion efficiency decay after 16 days test at room temperature and yields a conversion efficiency of 1.5% during long-term stability measurement at 90 °C under white light irradiation of 100 mW cm−2. The new solvent-free polysiloxane copolymer electrolyte can be good candidate for next generation DSSC.

Advancing beyond current generation dye-sensitized solar cells

The most efficient dye-sensitized solar cells (DSSCs) have had essentially the same configuration (nanoparticle TiO2 sensitized with [Ru(4,4′-dicarboxy-2,2′-bipyridine)2(NCS)2] in contact with I3−/I−) for the last 17 years. In this article we outline the strategies for improving each of the three major photo-relevant components of a DSSC, review literature reports consistent with these strategies and suggest future directions. Finally we explore the potential of future generation DSSCs for advancing energy-conversion performance.