Working from Both Sides: Composite Metallic Semitransparent Top Electrode for High Performance Perovskite Solar Cells

We report herein perovskite solar cells using solution-processed silver nanowires (AgNWs) as transparent top electrode with markedly enhanced device performance, as well as stability by evaporating an ultrathin transparent Au (UTA) layer beneath the spin-coated AgNWs forming a composite transparent metallic electrode. The interlayer serves as a physical separation sandwiched in between the perovskite/hole transporting material (HTM) active layer and the halide-reactive AgNWs top-electrode to prevent undesired electrode degradation and simultaneously functions to significantly promote ohmic contact. The as-fabricated semitransparent PSCs feature a <i>V</i>_oc of 0.96 V, a <i>J</i>_sc of 20.47 mA cm^–2, with an overall PCE of over 11% when measured with front illumination and a <i>V</i>_oc of 0.92 V, a <i>J</i>sc of 14.29 mA cm^–2, and an overall PCE of 7.53% with back illumination, corresponding to approximately 70% of the value under normal illumination conditions. The devices also demonstrate exceptional fabrication repeatability and air stability

High Efficiency Inverted Planar Perovskite Solar Cells with Solution-Processed NiO_<i>x</i> Hole Contact

NiO_<i>x</i> is a promising hole-transporting material for perovskite solar cells due to its high hole mobility, good stability, and easy processability. In this work, we employed a simple solution-processed NiO_<i>x</i> film as the hole-transporting layer in perovskite solar cells. When the thickness of the perovskite layer increased from 270 to 380 nm, the light absorption and photogenerated carrier density were enhanced and the transporting distance of electron and hole would also increase at the same time, resulting in a large charge transfer resistance and a long hole-extracted process in the device, characterized by the UV–vis, photoluminescence, and electrochemical impedance spectroscopy spectra. Combining both of these factors, an optimal thickness of 334.2 nm was prepared with the perovskite precursor concentration of 1.35 M. Moreover, the optimal device fabrication conditions were further achieved by optimizing the thickness of NiO_<i>x</i> hole-transporting layer and PCBM electron selective layer. As a result, the best power conversion efficiency of 15.71% was obtained with a <i>J</i>_sc of 20.51 mA·cm^–2, a <i>V</i>_oc of 988 mV, and a FF of 77.51% with almost no hysteresis. A stable efficiency of 15.10% was caught at the maximum power point. This work provides a promising route to achieve higher efficiency perovskite solar cells based on NiO or other inorganic hole-transporting materials