Dye-sensitized solar cell (DSSC) offers an efficient and easily implemented technology for future energy supply. Compared to conventional silicon solar cells, it provides comparable power conversion efficiency (PCE) at low material and manufacturing costs. DSSC materials such as titanium oxide (TiO 2 ) are inexpensive, abundant and innocuous to the environment. Since DSSC materials are less prone to contamination and processable at ambient temperature, a roll-to-roll process could be utilized to print DSSCs on the mass production line. DSSCs perform better under lower light intensities, which makes them an excellent choice for indoor applications. Due to the advancement of molecular engineering, colored and transparent thin films have been introduced to enhance the aesthetic values. Up to now, such benefits have attracted considerable research interests and commercialization effort. Here, this review examines advanced techniques and research trends of this promising technology from the perspective of device modeling, state-of-art techniques, and novel device structures.

Review on dye-sensitized solar cells (DSSCs): Advanced techniques and research trends

Dye sensitized solar cell converts visible light into electricity using sensitization of the cell. Performances of dye sensitized solar cells are mainly based on dye used as a sensitizer. Now a days study of dyes extracted from natural resources is the main concern for researchers. Application of natural dyes is a promising development in the field of this technology. Natural dyes are cutting down high cost of metal complex sensitizers and also replacing expensive chemical synthesis process through simple extraction process. Natural dyes are abundant, easily extractable, safe material causes no environment threat. These can be extracted from flowers petals, leaves, roots and barks in the form of anthocyanin, carotenoid, flavonoid and chlorophyll pigments. This review discusses development of natural dyes and their effect on various performance parameters of dye sensitized solar cell.

Natural dyes for dye sensitized solar cell: A review

As an emerging photovoltaic technology, dye-sensitized solar cells (DSSCs) have attracted a great deal of academic and industrial interest due to their reasonably high power conversion efficiency, low material cost and facile fabrication process. Metal-free organic dyes, as one of the key components of DSSCs, play a pivotal role in light harvesting and electron injection. Among the various species of organic dyes, easily tunable 10H-phenothiazine-based dyes hold a large proportion. The electron-rich nitrogen and sulfur atoms render 10H-phenothiazine a stronger donor character than other amines, even better than triphenylamine, tetrahydroquinoline, carbazole and iminodibenzyl. On the other hand, the unique non-planar butterfly conformation of the 10H-phenothiazine ring can sufficiently suppress molecular aggregation and the formation of excimers. The positions N-10, C-3 and C-7 of the 10H-phenothiazine ring system can easily be furnished with electron-donating or electron-withdrawing groups. Thus, the structural features of 10H-phenothiazine-based dyes guarantee the fabrication of efficient DSSCs. Some 10H-phenothiazine-based dyes show high photovoltaic performance, even better than the commercial ruthenium complex (N719). This paper reviews the recent significant scientific progress in 10H-phenothiazine-based DSSCs and focuses especially on the relationship between the molecular structure and the photoelectric conversion properties.

Phenothiazine-based dyes for efficient dye-sensitized solar cells

The dyes extracted from pomegranate and berry fruits were successfully used in the fabrication of natural dye sensitized solar cells (NDSSC). The morphology, porosity, surface roughness, thickness, absorption and emission characteristics of the pomegranate dye sensitized photo-anode were studied using various analytical techniques including FESEM, EDS, TEM, AFM, FTIR, Raman, Fluorescence and Absorption Spectroscopy. Pomegranate dye extract has been shown to contain anthocyanin which is an excellent light harvesting pigment needed for the generation of charge carriers for the production of electricity. The solar cell’s photovoltic performance in terms of efficiency, voltage, and current was tested with a standard illumination of air-mass 1.5 global (AM 1.5 G) having an irradiance of 100 mW/cm2. After optimization of the photo-anode and counter electrode, a photoelectric conversion efficiency (η) of 2%, an open-circuit voltage (Voc) of 0.39 mV, and a short-circuit current density (Isc) of 12.2 mA/cm2 were obtained. Impedance determination showed a relatively low charge-transfer resistance (17.44 Ω) and a long lifetime, signifying a reduction in recombination losses. The relatively enhanced efficiency is attributable in part to the use of a highly concentrated pomegranate dye, graphite counter electrode and TiCl4 treatment of the photo-anode.

Fabrication, Optimization and Characterization of Natural Dye Sensitized Solar Cell.

In this report, a pivotal improvement in the performance of dye-sensitized solar cells has been achieved, thus taking it one step closer toward the commercialization. Through the stepwise modification on the anthracene-based organic sensitizers, the alteration of alkyl to alkoxy chain and incorporation of electron deficient moieties in the new sensitizing dyes TY3, TY4, and TY6 are found to play a significant role in the efficiency enhancement. The dye TY6, when tested under 1 sun (AM 1.5G) illumination, is found to exhibit the best efficiency of 8.08% in the series reported here. Taking it further, sensitizer TY6 achieves a milestone by displaying an efficiency of 28.56% when tested under T5 fluorescent illumination of 6000 lux and 20.72% under same illuminance from a commercial light emitting diode light source. Such an excellent performance can be attributed to its outstanding J SC and V OC, which are characteristic properties of these anthracene dyes.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/aenm.201802405

New Acetylene‐Bridged 9,10‐Conjugated Anthracene Sensitizers: Application in Outdoor and Indoor Dye‐Sensitized Solar Cells

Dye Sensitized Solar Cell (DSSC) is considered to be one of the most promising technological developments in the field of Solar Cells. It is basically a cell that imitates the process seen in plant cells to produce energy. It is a photo-electrochemical cell, considering the electron moments caused by the combined effect of the photon energy and the chemical reactions. The DSSC being transparent to some extent and comparatively cheaper than conventional solar photo-voltaic, can be a potential energy source for the future. But there are many aspects that need to be worked upon before declaring it as a feasible commercial product. The paper emphasizes on these aspects and the various improvements that the DSSC has gone through in recent years. This is a detailed review of the work done to improve the performance of DSSC, with supporting data. A comparative study of the effect of various suggested modification to the different components of DSSC has been done. This would give a clear idea about the most recent improvements done in DSSC with respect to the various components. It includes a summary of the suggested improvements by various researchers, bifurcated into different sections with respect to the different components of the DSSC. It was observed that incorporating graphene sheets of various sizes in the photo anode helped to improve the efficiency of DSSC significantly, giving a maximum efficiency of 6.62%. In case of novel dyes used in the DSSC fabrication the D-A-pi-A indoline dyes showed a great enhancement in the cell efficiency, with efficiency of up to 6.9%. Incorporation of Pt in counter electrodes and 3D-CE also showed notably good efficiency in DSSC, the efficiency improving up to 8.8%.

Recent improvements in dye sensitized solar cells: A review

In the 21st century solar energy is predicted to serve as a major source of energy, being the only source having the potential to fulfill the ever increasing energy needs. Most of the large scale solar farms employ flat plate photovoltaic concept, so the installation footprint and shadow effect causes a huge drop in the electrical efficiency of the system. This paper aims at developing a methodology to reduce the area requirements in solar power generation. It proposes the development of a triangular prism shaped solar photovoltaic unit, which would reduce the required area for installation of the panels as opposed to the conventional method. The paper consists of the study of a lab level experimental setup of the proposed model, and comparison of its performance with conventional flat plate solar cells. The use of reflecting mirrors within the setup helps improve the efficiency of the setup, than the panels placed in the same area by conventional method. It also includes scope of future development.

Elsa John

Papers

Recent improvements in dye sensitized solar cells: A review

Design, development and testing of a novel triangular prism shaped solar cell