Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Dye-sensitized solar cells (DSSCs) belong to the group of thin-film solar cells which have been under extensive research for more than two decades due to their low cost, simple preparation methodology, low toxicity and ease of production. Still, there is lot of scope for the replacement of current DSSC materials due to their high cost, less abundance, and long-term stability. The efficiency of existing DSSCs reaches up to 12%, using Ru(II) dyes by optimizing material and structural properties which is still less than the efficiency offered by first- and second-generation solar cells, i.e., other thin-film solar cells and Si-based solar cells which offer ~ 20–30% efficiency. This article provides an in-depth review on DSSC construction, operating principle, key problems (low efficiency, low scalability, and low stability), prospective efficient materials, and finally a brief insight to commercialization.

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Dye-Sensitized Solar Cells: Fundamentals and Current Status

Quantum dot-sensitized solar cells (QDSCs) have emerged as a promising candidate for next-generation solar cells due to the distinct optoelectronic features of quantum dot (QD) light-harvesting materials, such as high light, thermal, and moisture stability, facilely tunable absorption range, high absorption coefficient, multiple exciton generation possibility, and solution processability as well as their facile fabrication and low-cost availability. In recent years, we have witnessed a dramatic boost in the power conversion efficiency (PCE) of QDSCs from 5% to nearly 13%, which is comparable to other kinds of emerging solar cells. Both the exploration of new QD light-harvesting materials and interface engineering have contributed to this fantastically fast improvement. The outstanding development trend of QDSCs indicates their great potential as a promising candidate for next-generation photovoltaic cells. In this review article, we present a comprehensive overview of the development of QDSCs, including: (1) the fundamental principles, (2) a history of the brief evolution of QDSCs, (3) the key materials in QDSCs, (4) recombination control, and (5) stability issues. Finally, some directions that can further promote the development of QDSCs in the future are proposed to help readers grasp the challenges and opportunities for obtaining high-efficiency QDSCs.

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Quantum dot-sensitized solar cells

Recent advances in eco-friendly and cost-effective materials towards sustainable dye-sensitized solar cells

Metal–organic framework (MOF) materials have achieved significant research interest in the fields of gas storage and separation over the last two decades because of the need for hydrogen utilization and carbon dioxide reduction. Besides, recently numerous functional MOFs have been exploited and applied in the optoelectronic field owing to some unique properties of MOF materials in those photovoltaic devices with enhanced performance and stability. This review focuses on the comprehensive summary of recent representative progress in the applications of MOFs in solar cell devices, including dye-sensitized solar cells, organic–inorganic hybrid perovskite solar cells, and organic solar cells, aiming to portray their prospects in the future.

Harnessing MOF materials in photovoltaic devices: recent advances, challenges, and perspectives

Dye-sensitized solar cells (DSSCs) are regarded as prospective solar cells for the next generation of photovoltaic technologies and have become research hotspots in the PV field. The counter electrode, as a crucial component of DSSCs, collects electrons from the external circuit and catalyzes the redox reduction in the electrolyte, which has a significant influence on the photovoltaic performance, long-term stability and cost of the devices. Solar cells, dye-sensitized solar cells, as well as the structure, principle, preparation and characterization of counter electrodes are mentioned in the introduction section. The next six sections discuss the counter electrodes based on transparency and flexibility, metals and alloys, carbon materials, conductive polymers, transition metal compounds, and hybrids, respectively. The special features and performance, advantages and disadvantages, preparation, characterization, mechanisms, important events and development histories of various counter electrodes are presented. In the eighth section, the development of counter electrodes is summarized with an outlook. This article panoramically reviews the counter electrodes in DSSCs, which is of great significance for enhancing the development levels of DSSCs and other photoelectrochemical devices.

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Counter electrodes in dye-sensitized solar cells

The invention relates to a method for preparing the nanometer Titania film of dope sensitized solar-energy battery. Wherein, it uses organic titanate as titania source, uses polymer template solvent, to be dissolved in organic solvent to prepare initial slurry, and uses silk screen print technique to print titania film at the surface of conductive glass, then treats at high temperature to obtain the nanometer titania film. The inventive product has high transmission rate, large surface area, high stability and long service life. And the invention has low cost while it can be used in optical catalyst, glass plating, and sensor.

Method for preparing nanocrystalline titanium dioxide film used by dye sensitization solar battery

The invention is concerned with the dye- sensitized nanocrystalline solar cell with the conductive polymer electrode and it's making method. It belongs to the storage cell, solar cell field. It is: uses the conductive polymer as the matrix, adds it into the solvent as the dispersant to make the conductive polymer colloid by dispersion and gelatinization under certain condition, then, coating the conductive polymer onto the surface of the conductive glass to generate the conductive polymer electrode with highly conductivity after the solvent volatilized. The invention solves the problems of the usage of the platinum electrode with high cost but low product life cycle dues to certain chemical reaction currently. It is with the simple making method, high conductivity, low cost, high stability and longer product life cycle.

Conductive polymer for dye-sensitized nano crystal solar battery and its making method

In the preparation process of AS resin/N-alkyl pyridine iodine salt polymer gel electrolyte, AS resin is first used as support medium and proper amount of organic small molecular plasticizer and additive is added to form gel polymer substrate; and proper amount of oxidation-reduction coupule comprising N-alkyl pyridine iodine salt and iodine is then added and dissolved inside the gel polymer substrate to form the AS resin/N-alkyl pyridine iodine salt polymer gel electrolyte. The electrolyte has room temperature conductivity of 3-8 mS/cm, similar to that of liquid electrolyte in dye sensitizednanometer crystal TiO2 solar cell, and may be used in dye sensitized nanometer crystal TiO2 solar cell to obtain similar performance. the conductive polymer may find wide application in secondary cell, electroluminescence, sensor and other fields.

Miaoliang Huang

Papers

Counter electrodes in dye-sensitized solar cells

Method for preparing nanocrystalline titanium dioxide film used by dye sensitization solar battery

Conductive polymer for dye-sensitized nano crystal solar battery and its making method

Prepn of AS resin/N-alkyl pyridine iodine salt polymer gel electrolyte