Toward Solution-Processed High-Performance Polymer Solar Cells: from Material Design to Device Engineering

Abstract

With the rapid development of polymer solar cells (PSCs), the manufacture of high-performance large area PSC modules is becoming a critical issue in commercial applications. However, most of the reported light absorption materials and interfacial materials are quite thickness sensitive, with optimal thicknesses of around 100 and 5 nm, respectively. The thickness need to be precisely controlled, otherwise, a small variation in thickness can often lead to a sharp decrease in device performance, especially for interfacial materials. This increases the difficulty of apply these materials in the production of large area PSCs. To avoid the shortcomings of thickness-sensitive materials and achieve high-performance large area PSC modules, we designed and synthesized a series of high mobility donor materials and cathode interfacial materials. These materials exhibited excellent device performance at their optimal thicknesses and maintained high performance even with large thickness variations, thus providing a solution to the bottleneck problem in manufacturing PSC modules and enhancing the device reproducibility. We also developed a simple and efficient approach for achieving a large area cathode interlayer with controlled film composition, uniformity, and thickness at the nanometer-scale using an electrostatic layer-by-layer self-assembly (eLbL) process. The eLbL films exhibited excellent cathode modification ability and can be integrated into the current large area device processing techniques. Thus, our approaches from both material design to device engineering provide new solutions for preparing high-performance large area PSC modules.

Environmentally Friendly Solvent‐Processed Organic Solar Cells that are Highly Efficient and Adaptable for the Blade‐Coating Method

“…To screen out a donor–acceptor combination with the best photovoltaic performance for further investigation on coating methods, we first take chloroform and a trace amount of diiodooctane (DIO, 0.5% in volume ratio)—which are commonly used as a main solvent and solvent additive, respectively—to make the solutions of the photoactive materials and fabricate the active layers by spin‐coating. The NF‐OSCs with a configuration of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene):poly(styrene‐sulfonate)/polymer donor: NF acceptor/PFN‐Br/Al were fabricated (see Figure ), where PFN‐Br was used as the cathode interlayer, and later tested under simulated AM1.5G illumination with an intensity of 100 mW cm −2 . The weight ratio between the donor and the acceptor in the three types of blends was kept at 1:1, and the optimal thickness of the blend film was ≈100 nm.…”

Improvement of Photovoltaic Performance of Polymer Solar Cells by Rational Molecular Optimization of Organic Molecule Acceptors

“…[1][2][3][4] Most of the investigations in the past decade have focused on the design and synthesis of highly efficient polymer donors, [3][4][5][6][7][8][9] which leads to the fullerene-based devices with power conversion efficiencies (PCEs) over 10%. [1][2][3][4] Most of the investigations in the past decade have focused on the design and synthesis of highly efficient polymer donors, [3][4][5][6][7][8][9] which leads to the fullerene-based devices with power conversion efficiencies (PCEs) over 10%.…”

Efficient Large Area Organic Solar Cells Processed by Blade‐Coating With Single‐Component Green Solvent

“…One way to overcome these problems is to develop new coating methods to precisely control the film thickness and achieve highly uniform active layer over large area . An alternative way is to adopt active layer materials that retain high performance over a very wide range of thicknesses to supply a wide processing window for large area coating techniques . Highly efficient thickness insensitive solar cells have been realized with few organic materials systems only when the active layer is deposited at elevated temperatures; because of the enhanced intermolecular interactions at low temperatures often resulting in too large domains.…”