Ionic Liquids Roles and Perspectives in Electrolyte for Dye-Sensitized Solar Cells

Abstract

Exploration of renewable energy, such as solar energy, is imminent not only to cater to the escalating energy demand but also to address the uprising environmental issues due to heavy usage of non-renewable fossil fuel. The dye-sensitized solar cells (DSSCs) which are considered as the third-generation solar cells, have a huge potential to be commercialized due to their low cost, simplicity in fabrication, and promising photon-to-electrical energy conversion efficiency. Nevertheless, a high cell efficiency can only be achieved when an organic solvent is incorporated into the formulation of the electrolyte, which is prone to evaporation and leakage. As a result, DSSCs become unsuitable for long-run usage due to thermal instability in the electrolyte. The early intention of incorporating ionic liquids (ILs) into the electrolyte was to curb the abovementioned problem and to enable the DSSCs to function as a sustainable energy device. As such, this article briefly reviews how ILs have been incorporated into the electrolyte formulation and the extent of how the ILs can affect the cell efficiency in various electrolyte states. The role of the ILs in a range of electrolytes is also highlighted. This sheds light on the true purpose of introducing ILs into DSSC electrolyte, which is to enhance the ionicity of the electrolyte.

Solvent Engineering as a Vehicle for High Quality Thin Films of Perovskites and Their Device Fabrication

“…The properties of ILs strictly depend on the interaction between these anions and cations inside the liquid and their structures. [77] In 2015, Moore et al used methylammonium formate (MAF) as the IL-based precursor solvent for perovskite solution and investigate the crystallization of MAPbI 3 thin films. [78] Using wide-angle X-ray scattering (WAXS) during the annealing step, the lack of an intermediate structure was demonstrated.…”

“…The properties of ILs strictly depend on the interaction between these anions and cations inside the liquid and their structures. [ 77 ]…”

Poly(3,4‐ethylenedioxythiophene) in Dye‐Sensitized Solar Cells: Toward Solid‐State and Platinum‐Free Photovoltaics

“…This pushed the scientific community to develop quasi-solid electrolytes, that is, systems possessing-at the same timethe cohesive properties of a solid and the ionic conduction of a liquid. [114][115][116] Three main strategies are now established when proposing quasi-solid DSSCs: i) The solidification of a liquid electrolyte through an organic polymeric gelator, obtaining thermoplastic or thermosetting systems; [117,118] ii) the solidification of a liquid electrolyte by inorganic nanoparticles (NPs), leading to composite systems; [119] iii) the use of ionic liquids to replace organic solvents (and sometimes also the redox shuttle), with the subsequent solidification with organic or inorganic gelators; [120] ionic liquids benefit from very low volatility and chemical stability, but their use is still controversial due to the often impactful synthesis. Overall, quasi-solid DSSCs have often demonstrated a promising long-term stability and rather high PCE values; [121][122][123][124] on the other hand, the permeation of these electrolytes in the whole thickness of nanostructured photoanodes has rarely been demonstrated, this latter representing a relevant pitfall in this field (i.e., only the first few layers would work in the TiO 2 -based photoanode).…”

Group of Uniform Materials Based on Organic Salts (GUMBOS): A Review of Their Solid State Properties and Applications

“…This study determined that this redox system rapidly regenerated indoline dyes within the range of tens of nanoseconds, several orders of magnitude faster than cobalt(II/III) shuttle [Co(bp y) 3 ] 2+/3+ [NTf 2 ] 3/2 [225]. As a result of the volatility of the organic solvent employed in electrolyte solutions, some groups have expanded investigations into non-volatile routes for DSSC fabrication [212,226,227]. Cao and coworkers have developed a solid-state DSSC (ssDSSC) based on [Cu(tmby) 2 ] +/2+ [NTf 2 ] 2 redox shuttle for a hole transport layer [228].…”