A review on carbon nanotube/polymer composites for organic solar cells

Abstract

SUMMARY Carbon nanotubes (CNTs) have unique properties, such as their electrical conductivity, that enable them to be combined with conducting polymers to form composites for use in organic solar cells (OSCs). It is envisaged that the improved composite has a higher efficiency of green energy and will reduce the cost of these cells. The use of such alternative energy sources also drastically reduces overuse of fossil fuels and consequently limits environmental degradation. This review compares research and performance between conventional silicon solar cells and OSCs. It also discusses OSC photoexcitation and charge carrier generation with the incorporation of CNTs, physicochemical properties of the composites and other factors that affect the efficiencies of OSCs. In addition, properties of CNTs that favour their dispersion in polymer matrices as acceptors and charge carriers to the electrodes are covered. The effects of CNTs containing dopants, such as nitrogen and boron, on charge transfer are discussed. Also, the fabrication techniques of OSCs that include CNT/polymer composite processing and the methods of film deposition on the substrate are described. Finally, the case studies of OSCs containing polymers with single‐walled CNTs, double‐walled CNTs or multi‐walled CNTs are evaluated. Copyright © 2014 John Wiley & Sons, Ltd.

Low temperature synthesis of multiwalled carbon nanotubes and incorporation into an organic solar cell

“…Technological advancement and population growth has brought about a huge demand for energy globally [1][2][3]. Renewable sources of energy are seen as viable alternatives in an effort to meet the growing energy demand, as well as to reduce greenhouse gas emissions and other deleterious environmental effects which occur from using fossil fuels.…”

“…Amongst the possible renewable sources; solar energy is considered as an inexhaustible and relatively clean source of energy. Considerable and continual efforts to utilise this sustainable energy supply has been a global focus for the last few decades [2][3][4]. This includes development of modified energy storage and conversion devices such as batteries [5], super capacitors [6], light emitting diodes (LEDs) [7], and solar cells [2,3,8].…”

“…These include dye sensitised solar cells (DSSC) [9], inorganic and organic solar cells (OSC) [2,3,8,10], and various other hybrid systems [2,3]. Widespread and most commercially successful systems are inorganic solar cells; specifically silicon based, and these can be monocrystalline [11], polycrystalline [12], or amorphous [13].…”

“…Widespread and most commercially successful systems are inorganic solar cells; specifically silicon based, and these can be monocrystalline [11], polycrystalline [12], or amorphous [13]. These types of solar cells are made from very reliable and advanced processing technologies, and have been reported to have relatively high efficiency rates [2,14]. However, the fabrication techniques of these devices can be very expensive as they require huge labour and investments on the requisite facilities [10].…”

“…However, the fabrication techniques of these devices can be very expensive as they require huge labour and investments on the requisite facilities [10]. On the other hand, solar cells fabricated from organic semiconductor materials are likely to be much cheaper since they can be potentially assembled using current polymer processing technologies, and such systems can take advantage of the inherent advantages associated with polymers in terms of construction, design, aesthetic appeal, and flexibility in application [2]. However, to date, solar cells made from organic semiconductor polymers are less efficient than inorganic systems, and are prone to environmental degradations [2,3,8].…”