Progress in flexible dye solar cell materials, processes and devices

Abstract

Flexible Dye Solar Cells (FDSCs), in their most widespread architecture, are assembled with two opposing planar films or foil substrates in metal–plastic or plastic–plastic combinations. The use of one metal electrode enables the convenient utilization of materials and high temperature processes but is accompanied by issues including partial opacity of the electrolyte and catalyst layer. Constraints on the stability of plastic substrates have led to the development of a variety of alternative material formulations and processes to guarantee performance even at low temperatures compatible with plastic films. Recently, efforts in doing without transparent conducting oxides have led to the development of new unconventional architectures. Review of the operation of DSCs shows that initial target markets are represented by indoor applications where power output densities have been shown to outperform competing flexible photovoltaic technologies. Whereas performance, stability in particular, needs to be significantly improved for the adoption in long term outdoor installations, commercial products integrating FDCSs for indoor or portable use have already been launched. Issues pertaining progress in materials, processes, devices and industrialization of FDSCs will be analyzed and discussed in this review

Research Update: Large-area deposition, coating, printing, and processing techniques for the upscaling of perovskite solar cell technology

“…31,57 R2R has been implemented successfully already in solar cell manufacturing, especially in the field of organic solar cells [58][59][60] and even DSCs. 61 Although many groups have used R2R-compatible printing techniques on glass including slot-die, 30,31 inkjet, 62 and blade coating, 26 the deposition parameters (coating speed, flow rate, temperature, drying, materials) 56,63 must be optimized newly when depositing on flexible substrates. Hwang et al 31 optimized ETL, perovskite, and HTL printed deposition through slot-die on PET/ITO substrates with a vacuum evaporated Ag back electrode.…”

Progress, challenges and perspectives in flexible perovskite solar cells

“…Efficiencies of 16.3% have been reported in triple junction amorphous silicon devices on polyimide, 13.6% in CdTe on metal and 20.4% in CIGS on a polyimide. 18 For…”

“…For this reason, research on flexible DSCs has been divided among groups focusing on metal substrates (mainly Ti) and on PET/ITO films. 18 For PET/ITO it has been necessary to develop low temperature processes, while metal foils allow the use of conventional high temperature processes but the amount of light reaching the active dye sensitized layer is reduced by absorption through the non-transparent electrolyte.…”

“…Thus, technologies such as DSCs and OPVs that have been researched for over two decades, whilst demonstrating lower PCE (of the order of 12-14% in laboratory cells), are now being developed industrially to compete on markets where their added functionalities can deliver properties which c-Si cannot easily, such as transparency, color/shape control, high performance under diffuse or indoor light, and flexibility, 18 making them suitable and very interesting initially for building-integrated, automotive or for light weight portable or indoor applications. 7 Perovskite solar cells are a much more recent PV discovery.…”

“…54 Importantly, developing perovskite photovoltaic module technology on thin flexible plastics permits rapid web-based reel-to-reel manufacturing and potentially massive product volumes and throughputs thus contributing to cutting industrial costs. 18 Developing the technology on plastics brings about a series of non-trivial challenges and issues related to the nature of the substrates which are not present on glass substrates (i.e. distortions, low temperature processing only).…”