Flexible organic/inorganic hybrid solar cells based on conjugated polymer and ZnO nanorod array

Abstract

We report on the photovoltaic characteristics of organic/inorganic hybrid solar cells fabricated on 'flexible' transparent substrates. The solar cell device is composed of ZnO nanorod array and the bulk heterojunction structured organic layer which is the blend of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C61 butyric acid methyl ester (PCBM). The ZnO nanorod array was grown on indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates via a low-temperature (85 • C) aqueous solution process. The blend solution consisting of conjugated polymer P3HT and fullerene PCBM was spin coated at a low spinning rate of 400 rpm on top of the ZnO nanorod array structure and then the photoactive layer was slow dried at room temperature in air to promote its infiltration into the nanorod network. As a top electrode, silver was sputtered on top of the photoactive layer. The flexible solar cell with the structure of PET/ITO/ZnO thin film/ZnO nanorods/P3HT:PCBM/Ag exhibited a photovoltaic performance with an open circuit voltage (V OC ) of 0.52 V, a short circuit current density (J SC ) of 9.82 mA cm −2 , a fill factor (FF) of 35% and a power conversion efficiency (η) of 1.78%. All the measurements were performed under 100 mW cm −2 of illumination with an air mass 1.5 G filter. To the best of our knowledge, this is the first presentation of investigation into the fabrication and characterization of organic/inorganic hybrid solar cells based on bulk heterojunction structured conjugated polymer/fullerene photoactive layer and ZnO nanorod array constructed on flexible transparent substrates.

Substrate‐Oriented Nanorod Scaffolds in Polymer–Fullerene Bulk Heterojunction Solar Cells

“…This type of solar cell has been studied by using a variety of inorganic and organic donor/acceptor material combinations with successful, though not necessarily conclusive results. [16,17,[22][23][24][25][26][27][28] Herein we attempt to answer the question: Does a substrate-oriented nanorod scaffold improve the functionality of polymer-fullerene BHJ solar cells? Specifically we compare the published efficiency values of the most common material combinations (ZnO scaffold with poly(3-hexylthiophene):phenyl C 61 -butryric acid methyl ester (P3HT:PCBM) and Ag, or poly(3,4ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/ Ag.…”

Nanostructured conformal hybrid solar cells: a promising architecture towards complete charge collection and light absorption

“…As in the case of conventional Thick/NR hybrid cells, where efficiencies have been increased by varying the characteristics of the nanorod arrays [25,27,28,31,42,43] or by introducing a top blocking layer, [24,44] the control experiment presented here is expected to yield even higher efficiencies in the future by applying similar optimizations. Some clear strategies would include the control of the surface of the nanorods, which has been shown to play an important role in hybrid cells[45-49], the deposition of a highly conformal top blocking layer (such as PEDOT:PSS [50] or WO 3 [51]) and the improvement of the conformal top contact coverage.…”

“…Although other studies involving similar core-shell, conformal architectures using silicon nanorod arrays have been reported [23,26], to the best of our knowledge, this is the first study in which an oxide in combination with a thin film of an organic bulk heterojunction blend is studied. The use of an organic blend is advantageous since exciton dissociation can be more efficient at the interface between the two organic semiconductors than at the interface with ZnO [27,28]. …”

Recent advances in flexible perovskite solar cells

“…Moreover, the acidic and hygroscopic nature of PEDOT:PSS has a negative impact on the long-term stability. To optimize the PCBM layer thickness, four devices with varied PCBM layer thickness (45,55,80, and 100 nm) were fabricated by keeping other conditions constant. Therefore, to apply a uniform and dense layer of perovskite on PCBM, Ryu et al 114 used modified solvent engineering process employing a diethyl ether drip as an orthogonal solvent enabled fabrication of a multi-layered device comprising FTO/polyethyleneimine (PEI)/PCBM/MAPbI 3 /poly(triaryl amine)(PTAA)/Au at low temperature (<100 o C).…”