Organic solar cell materials and active layer designs—improvements with carbon nanotubes: a review

Abstract

Organic solar cells offer an opportunity to diversify renewable energy sources owing to their low technological cost. They are amenable to large surfaces and can easily be integrated into buildings. It is necessary, however, to improve their energy efficiency and durability for the development of a sustainable technology. In these devices, photovoltaic conversion is based on the separation of photogenerated charges at an interface between electron donor and acceptor materials, which imposes some constraints on the photoactive layer of the cells. In this paper, which includes some of our studies, we address optimization of the active layer: absorption and exciton dissociation steps, the open-circuit voltage and the active layer morphology. A promising direction proposed to improve the active layer morphology and cell efficiency is the incorporation of highly anisotropic nanoparticles such as carbon nanotubes, which may facilitate charge transport to the electrodes. Dispersion and orientation of the nanotubes in the organic matrix are discussed and we suggest an ideal model polymer solar cell which will maximize performance of the cells by using carbon nanotubes in the active layer.

Effect of thermal annealing on the electrical properties of P3HT:PC70BM nanocomposites

“…Recently, considerable efforts have centered on understanding the photovoltaic mechanism [1,2]. The typical structure of these devices is a diode architecture consisting of a spin coated nanocomposite layer, where the active layer consists of heterojunction between donor and acceptor materials blended together [3][4][5][6].…”

Recent Approaches to Controlling the Nanoscale Morphology of Polymer-Based Bulk-Heterojunction Solar Cells

“…The exciton diffusion length is the distance travelled by the exciton before it undergoes recombination in the organic semiconductors, and it is around 10-20 nm [21]. In order to avoid exciton recombination, a factor which leads to a decrease in the PCE [22,23], the distance between the interface and the region of exciton generation must be of the same magnitude (10-20 nm), as the excitons generated within this interval are most likely to dissociate into free electrons and holes [24]. This highlights the importance of a carefully controlled active layer for the purpose of achieving high PCE values.…”

Recent Developments in Quantum Dots/CNT Co-Sensitized Organic Solar Cells

“…Organic materials with -conjugated structure are suitable candidates for the fabrication of organic solar cell [26]. These materials are categorized into two groups including electron donors and electron acceptors.…”

“…Hence CNT can serve as an efficient support for anchoring the light harvesting semiconductor QDs. Unlike the well-studied transport issues in QD-CNT based hybrid solar cells, [26] the impact of QD-CNT nanostructures on the morphology of the photoactive layer is less investigated.…”