Ultraviolet‐Durable Flexible Nonfullerene Organic Solar Cells Realized by a Hybrid Nanostructured Transparent Electrode

Abstract

A significant enhancement in ultraviolet (UV) durable indium tin oxide (ITO)-free flexible nonfullerene organic solar cells (OSCs) has been demonstrated using a hybrid nanostructured flexible transparent electrode (FTE), comprising a mixture of 0D silver nanoparticles (AgNPs), 1D Ag nanowires (AgNWs) and 2D exfoliated graphene sheets. The FTE exhibits high optical transparency and electric conductivity, good air stability and full-solution fabrication capability at a low processing temperature. An average power convention efficiency (PCE) of 8.15% has been obtained for the flexible nonfullerene OSCs, based on the blend of poly[(2,6-(4, 8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thi enyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c'] dithiophene-4,8-dione)] (PBDB-T): 3,9bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dit hieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b'] dithiophene (ITIC). The flexible PBDB-T:ITIC OSCs exhibit an excellent UV durability compared to the ITO-based control cell, realized by the tailored FTE absorption in wavelength < 380 nm. The novel FTE developed in this work provides a promising alternative to ITO for use in UV durable flexible OSCs, serving as a UV filter to impede an unavoidable UV-induced degradation in ITO-based OSCs.

Graphene‐Based Materials in Planar Perovskite Solar Cells

“…The graphene‐based TCSs have been verified to be a UV absorber, which can protect the device from UV light‐induced degradation. [ 120,121 ] However, there are a few works focusing on using graphene as the UV‐blocking material in planar PSCs that deserve more research attention.…”

Organic solar cells: Current perspectives on graphene‐based materials for electrodes, electron acceptors and interfacial layers

“…In a similar study, Ricciardulli et al 111 developed electrochemically exfoliated graphene (EG)-silver nanowire (AgNW) composite anodes for polythieno [3,4- Cu-G/PEDOT:PSS/PTB7-Th:PC 71 Interestingly, the G:GQDs:AgNWs managed to retain 94% of their initial PCE after 10 days of storage under environmental temperature and humidity, compared to the OSCs that were fabricated without the GQDs that lost 14% of their initial PCE. 113 On the other hand, the G:AgNWs: AgNPs-based devices also showed a slight decrease in PCE by 23% after exposure to ultraviolet (UV) radiation for 1 hour, as compared to the ITO-based control device, which showed a rapid decrease in PCE by 47% under the same conditions, 114 exhibiting the superior long-term operational stability of the graphene-based OSCs. Furthermore, GQDs:AgNWs and AgNWs-based devices 113 and the G: AgNWs:AgNPs-based devices 114 managed to retain above 90% of their initial PCE after a test of 1000 bends at a radius of 4 mm, as shown in Figure 4, which demonstrates their superior mechanical stability to the OSCs without graphene, thereby revealing the significance of graphenebased materials in enhancing device sustainability.…”

“…113 On the other hand, the G:AgNWs: AgNPs-based devices also showed a slight decrease in PCE by 23% after exposure to ultraviolet (UV) radiation for 1 hour, as compared to the ITO-based control device, which showed a rapid decrease in PCE by 47% under the same conditions, 114 exhibiting the superior long-term operational stability of the graphene-based OSCs. Furthermore, GQDs:AgNWs and AgNWs-based devices 113 and the G: AgNWs:AgNPs-based devices 114 managed to retain above 90% of their initial PCE after a test of 1000 bends at a radius of 4 mm, as shown in Figure 4, which demonstrates their superior mechanical stability to the OSCs without graphene, thereby revealing the significance of graphenebased materials in enhancing device sustainability.…”

“…The deviation in performance was mainly ascribed to the low absorption of photons in the active layer because of the low transmittance of the PEN substrate. Interestingly, the OSCs retained 99% of their initial PCE after being subjected to 150 bending cycles, demonstrating the mechanical robustness and flexibility of EG films.Also, Shin et al113 and Xu et al,114 respectively used nanostructured hybrid anodes made up of G:graphene Photovoltaic parameters of BHJ-OSCs with carbon-based materials…”

Highly-robust, solution-processed flexible transparent electrodes with a junction-free electrospun nanofiber network

“…However, coating the dissolved polymer is difficult to achieve in mass production, and reduced conductivity remains due to the junction of the network. To remove the junction, mechanical pressing, 22,23 annealing 24 and optical sintering 25 have been studied. These methods cause mechanical stresses in the substrate, and the metal network may be partially melted to form a bead.…”