To achieve efficient non-fullerene organic solar cells, it is important to reduce the voltage loss from the optical bandgap to the open-circuit voltage of the cell. Here we report a highly efficient non-fullerene organic solar cell with a high open-circuit voltage of 1.08 V and a small voltage loss of 0.55 V. The high performance was enabled by a novel wide-bandgap (2.05 eV) donor polymer paired with a narrow-bandgap (1.63 eV) small-molecular acceptor (SMA). Our morphology characterizations show that both the polymer and the SMA can maintain high crystallinity in the blend film, resulting in crystalline and small domains. As a result, our non-fullerene organic solar cells realize an efficiency of 11.6%, which is the best performance for a non-fullerene organic solar cell with such a small voltage loss.
The development of low‐cost, high‐performance, and stable electrocatalysts for the sluggish oxygen evolution reaction (OER) in water splitting is essential for renewable and clean energy technologies. Herein, the interconnected nanoarrays consisting of Co–Ni bimetallic metaphosphate nanoparticles embedded in a carbon matrix (Co2−xNixP4O12‐C) are fabricated through a mild phosphorylating process of cobalt–nickel zeolitic imidazolate frameworks (CoNi‐ZIF). Density functional theory calculations reveal moderate adsorption of oxygenated intermediates on the doping Ni site, and current density simulations imply homogeneous and higher current density due to the morphology integrity of the interconnected metaphosphate nanoarrays. As a consequence, the optimized Co1.6Ni0.4P4O12‐C affords a superior OER activity (η = 230 mV at 10 mA cm−2) and long‐term stability in alkaline media (1 m KOH) that are comparable to most reported catalysts. The strategy for balancing the doping effect and morphology effect provides a new perspective when designing and developing highly efficient electrocatalysts for energy conversion and storage applications.
We report an exploratory study on the crystal formation behavior of CsPbI 2 Br perovskite films by adding excess cesium iodide (CsI). Surprisingly, facile cocrystallization of CsI and CsPbI 2 Br in the form of spinodal decomposition is observed. Significantly, the two phases spontaneously form morphing into a remarkably uniform bicontinuous nanoscale blend with high orientational correlation through the wellmatched (110) plane of CsI and the (200) plane of CsPbI 2 Br. The CsPbI 2 Br films produced by the spinodal decomposition method not only enjoy a compact surface, low defect concentration, and long carrier lifetimes, they also retain their excellent charge transport property. By employing such a CsPbI 2 Br film for carbon-based perovskite solar cells, power conversion efficiency exceeding 10% is achieved with remarkable thermal stability. Our results provide valuable insight into the role of CsI in perovskite crystallization and a promising approach for designing inorganic halide perovskite-based devices.
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