Solution-Processed Flexible Polymer Solar Cells with Silver Nanowire Electrodes

Abstract

The conventional anode for organic photovoltaics (OPVs), indium tin oxide (ITO), is expensive and brittle, and thus is not suitable for use in roll-to-roll manufacturing of OPVs. In this study, fully solution-processed polymer bulk heterojunction (BHJ) solar cells with anodes made from silver nanowires (Ag NWs) have been successfully fabricated with a configuration of Ag NWs/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/polymer:phenyl-C(61)-butyric acid methyl ester (PCBM)/Ca/Al. Efficiencies of 2.8 and 2.5% are obtained for devices with Ag NW network on glass and on poly(ethylene terephthalate) (PET), respectively. The efficiency of the devices is limited by the low work function of the Ag NWs/PEDOT:PSS film and the non-ideal ohmic contact between the Ag NW anode and the active layer. Compared with devices based on the ITO anode, the open-circuit voltage (V(oc)) of solar cells based on the Ag NW anode is lower by ~0.3 V. More importantly, highly flexible BHJ solar cells have been firstly fabricated on Ag NWs/PET anode with recoverable efficiency of 2.5% under large deformation up to 120°. This study indicates that, with improved engineering of the nanowires/polymer interface, Ag NW electrodes can serve as a low-cost, flexible alternative to ITO, and thereby improve the economic viability and mechanical stability of OPVs.

Silver nanowire networks: Physical properties and potential integration in solar cells

“…[21][22][23][24] As mentioned, high haze factors result in light scattering into the device and increases the effective absorption cross section. The ability of AgNW networks to produce high haze networks while maintaining sufficient electro-optical properties shows the real potential to integrate them into solar cells.…”

“…[22] This type of solar cell could for instance be used as an energy producing window tinting. Another advantage of AgNW networks as front electrodes for photovoltaic applications is that they allow production of flexible solar cells, [21] which is difficult to achieve with TCOs due to their brittleness. Within the field of photovoltaics there are many different device architectures which have restrictions associated with them, for some such as Dye Sensitized Solar Cells and CdTe, the transparent electrode must be deposited first with high temperature processes to follow.…”

Solution-Processed Graphene-Based Transparent Conductive Electrodes as Ideal ITO Alternatives for Organic Solar Cells

“…One very promising technique is the employment of a mesh structure with periodic lines on the rGO film [53], with OSC devices based on graphene mesh electrodes (GMEs) already exhibiting performances comparable to those using conventional ITO TCEs [54,55]. Therefore, it is possible to control the films R s and transparency by tailoring the grid width, spacing, and thickness [56].…”

Interpenetrating heterojunction photovoltaic cells based on C60 nano-crystallized thin films

“…Thin-film organic photovoltaic cells (OPVs) have attracted tremendous attention for their promise to provide low cost and light weight devices that can absorb a large proportion of the solar spectrum [1][2][3][4][5][6][7]. OPVs commonly use either a planar heterojunction (PHJ) structure [8,9], which consists of donor-acceptor bilayer deposition, or a bulk heterojunction (BHJ) structure, which consists of a donor-acceptor mixture as shown in Fig.…”