Development of Annealing-Free, Solution-Processable Inverted Organic Solar Cells with N-Doped Graphene Electrodes using Zinc Oxide Nanoparticles

Abstract

An annealing-free process is considered as a technological advancement for the development of flexible (or wearable) organic electronic devices, which can prevent the distortion of substrates and damage to the active components of the device and simplify the overall fabrication process to increase the industrial applications. Owing to its outstanding electrical, optical, and mechanical properties, graphene is seen as a promising material that could act as a transparent conductive electrode for flexible optoelectronic devices. Owing to their high transparency and electron mobility, zinc oxide nanoparticles (ZnO-NP) are attractive and promising for their application as charge transporting materials for low-temperature processes in organic solar cells (OSCs), particularly because most charge transporting materials require annealing treatments at elevated temperatures. In this study, graphene/annealing-free ZnO-NP hybrid materials were developed for inverted OSC by successfully integrating ZnO-NP on the hydrophobic surface of graphene, thus aiming to enhance the applicability of graphene as a transparent electrode in flexible OSC systems. Chemical, optical, electrical, and morphological analyses of ZnO-NPs showed that the annealing-free process generates similar results to those provided by the conventional annealing process. The approach was effectively applied to graphene-based inverted OSCs with notable power conversion efficiencies of 8.16% and 7.41% on the solid and flexible substrates, respectively, which promises the great feasibility of graphene for emerging optoelectronic device applications.

Highly Flexible and Efficient All‐Polymer Solar Cells with High‐Viscosity Processing Polymer Additive toward Potential of Stretchable Devices

“…Their J – V characteristics were measured after different bending cycles at a bending radius of 3.0 mm. Note that a higher sheet resistance of the graphene electrode relative to that of ITO as well as the graphene transfer‐related defects may account for the slightly inferior device performances observed from the flexible devices . As shown in Figure a and Table S4 in the Supporting Information, although the 0PDPS afforded a higher PCE (5.89 %) initially, both J SC and FF dramatically degraded as the bending number increased, leading to significantly reduced PCE of only 3.10 %, that is, a decrease of 50 %, after 100 bending cycles.…”

Recent Advances in Growth and Modification of Graphene‐Based Energy Materials: From Chemical Vapor Deposition to Reduction of Graphene Oxide

“…The zinc oxide nanoparticles as electron transporting layer on CVD‐graphene surface could realize the uniform distribution of organic materials. The uniform organic materials accelerated the transfer of charge carrier, leading to power conversion efficiency up to 8.16% in OSC . Similarly, CVD‐graphene composites also play an important role in enhancing device performances.…”

“…The excellent compatibility of graphene as multifunctional material in various energy devices is attributed to the adjustability of physical property through different synthetic methods. For example, the nitrogen‐doped graphene obtained by chemical vapor deposition (CVD) as transparent electrode in organic solar cells showed good power conversion efficiency of 8.16% on solid substrates and 7.41% on flexible substrates, respectively; in lithium‐metal batteries, the 3D nanoporous nitrogen‐doped graphene prepared by CVD as scaffold material for loading lithium significantly improved the charge storage performances with long‐term cycling stability and ultrahigh rate capability; in supercapacitors, the sponge‐like 3D reduced graphene oxide (rGO) was functionalized by thionine, exhibiting high specific capacitance and outstanding flexibility; in hydrogen evolution reaction (HER), the holey rGO/Mo 2 N–Mo 2 C heterojunction exhibited great catalytic activity and superior stability . These latest studies show that graphene‐based materials synthesized by different methods have good performances in various energy devices.…”

Graphene- and Carbon-Nanotube-Based Transparent Electrodes for Semitransparent Solar Cells

“…An enormous amount of effort is being devoted to the development of transparent conductive films employing thin metallic films, conductive polymers, metal oxides, metal meshes, nanowire networks, carbon nanotubes (CNTs), and graphene [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. In particular, CNTs and graphene have received increasing attention because of their excellent optoelectronic properties, such as their high optical transparency, low sheet resistance, and high mobility.…”