Efficiency above 12% for 1 cm² Flexible Organic Solar Cells with Ag/Cu Grid Transparent Conducting Electrode

Abstract

With the rapid progress of organic solar cells (OSCs), improvement in the efficiency of large‐area flexible OSCs (>1 cm2) is crucial for real applications. However, the development of the large‐area flexible OSCs severely lags behind the growth of the small‐area OSCs, with the electrical loss due to the large sheet resistance of the electrode being a main reason. Herein, a high conductive and high transparent Ag/Cu composite grid with sheet resistance <1 Ω sq−1 and an average visible light transparency of 84% is produced as the transparent conducting electrode of flexible OSCs. Based on this Ag/Cu composite grid electrode, a high efficiency of 12.26% for 1 cm2 flexible OSCs is achieved. The performances of large‐area flexible OSCs also reach 7.79% (4 cm2) and 7.35% (9 cm2), respectively, which are much higher than those of the control devices with conventional flexible indium tin oxide electrodes. Surface planarization using highly conductive PEDOT:PSS and modification of the ZnO buffer layer by zirconium acetylacetonate (ZrAcac) are two necessary steps to achieve high performance. The flexible OSCs employing Ag/Cu grid have excellent mechanical bending resistance, maintaining high performance after bending at a radius of 2 mm.

High Power Conversion Efficiency of 13.61% for 1 cm2 Flexible Polymer Solar Cells Based on Patternable and Mass‐Producible Gravure‐Printed Silver Nanowire Electrodes

“…To the best of our knowledge, a 13.61% PCE is the highest reported value to date for the 1 cm 2 flexible OSCs. [ 16,36 ] In contrast, the PCE of the 1 cm 2 device prepared by the PET/AgNWs‐SP electrode was only 12.27%. The J SC and FF of the devices were significantly lower than those of the PET/AgNWs‐GV‐based cells.…”

“…The PET/AgNWs‐GV electrodes (RMS = 11.1 nm) had a lower roughness than the PET/AgNWs‐SP electrodes (RMS = 14.2 nm), which is in good accordance with the SEM results. Note that the surface roughness of the gravure‐printed AgNW was much lower than that of metal grid electrodes, [ 16,49,50 ] making this type of electrode highly compatible for the preparation of high‐performance OSCs. [ 17,51 ]…”

“…[ 1–5 ] In recent years, owing to the rapid developments in the synthesis of new organic semiconductors, [ 6–8 ] optimization of the active layer morphology, [ 9–11 ] and interface engineering, [ 12–14 ] the power conversion efficiency (PCE) of glass–indium tin oxide (ITO)‐based single‐junction PSCs has exceeded 18%. [ 15 ] However, the performance of flexible organic solar cells (OSCs) is still lagging, [ 16 ] particularly for large‐area devices, owing to the lack of high‐performance flexible transparent electrodes (FTEs). For use in flexible PSCs, high‐performance FTEs are required, which exhibit low sheet resistance, high light transmittance, low surface roughness, excellent flexibility, large‐area uniformity, and prepattern and mass production compatibility.…”

Synergistic Optimization Enables Large‐Area Flexible Organic Solar Cells to Maintain over 98% PCE of the Small‐Area Rigid Devices

“…To reduce the electronic loss, herein, a new type of flexible substrate, PET/silver-grid has been adopted ( Figure 1d), replacing the traditional PET/ITO substrate owing to its excellent attributes such as conductivity, light transmission, flexibility, etc. [17][18][19][20] The active layer morphology, flexible substrate properties and processing temperature have been optimized synergistically, which enabled large-area flexible OSCs (1 cm 2 ) to maintain over 98% PCE of the small-area (0.04 cm 2 ) rigid devices (12.16% vs 12.37%). Furthermore, the flexible OSCs exhibited good flexibility at a bending radius of 10 and 5 mm, as well as superior storage stability after being stored over 6000 h in a glove box.…”

Biomimetic Electrodes for Flexible Organic Solar Cells with Efficiencies over 16%

“…Thus, an optimized PCE of 16.1% was achieved by the PPZA‐based device, which is the highest value reported for single‐junction flexible OSCs (Table S1, Supporting Information). [ 19,28,50–54 ]…”