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.

Drop‐on demand inkjet‐printing (IJP) is a deposition technique with promise in the context of fabricating large‐area organic solar cells (OSCs) because of its high material usage, direct‐pattern, and large‐area roll‐to‐roll printing compatibility. But its feature of drop‐to‐drop deposition during IJP makes the film's drying and phase separation process different from spin‐coating, and forms different nanophase separation and vertical phase separation morphology. In this work, the nanophase separation of the inkjet‐printed organic blend films is systematically studied at different substrate temperatures. The results reveal that increasing the substrate temperature can suppress excess molecules aggregation owing to the high drying speed, leading to improved exciton dissociation efficiency in the blend films. However, the quick drying process at high temperature also leads to a homogenous vertical phase separation, which is not ideal for charge collection. Instead of printing the mixture of donor and acceptor solution directly to form the bulk‐heterojunction structure, the polymer donor is printed on the top of the acceptor surface, a so‐called layer‐by‐layer inkjet printing (LBL‐IJP) process. By using this LBL‐IJP route, balanced nanoscale phase aggregation and gradient vertical phase separation morphology are achieved, which leads to a record power conversion efficiency of 13.09% for the OSCs with an inkjet‐printed active layer.