Among new flexible transparent conductive electrode (TCE) candidates, ultrathin Ag film (UTAF) is attractive for its extremely low resistance and relatively high transparency. However, the performances of UTAF based TCEs critically depend on the threshold thickness for growth of continuous Ag films and the film morphologies. Here, we demonstrate that these two parameters could be strongly altered through the modulation of substrate surface energy. By minimizing the surface energy difference between the Ag film and substrate, a 9 nm UTAF with a sheet resistance down to 6.9 Ω sq−1 can be obtained using an electron-beam evaporation process. The resultant UTAF is completely continuous and exhibits smoother morphologies and smaller optical absorbances in comparison to the counterpart of granular-type Ag film at the same thickness without surface modulation. Template-stripping procedure is further developed to transfer the UTAFs to flexible polymer matrixes and construct Al2O3/Ag/MoOx (AAM) electrodes with excellent surface morphology as well as optical and electronic characteristics, including a root-mean-square roughness below 0.21 nm, a transparency up to 93.85% at 550 nm and a sheet resistance as low as 7.39 Ω sq−1. These AAM based electrodes also show superiority in mechanical robustness, thermal oxidation stability and shape memory property.

For semi-transparent perovskite solar cells (PSCs), the bombardment during the deposition of transparent conductive oxide can inevitably damage the underlying soft materials, thereby inducing a high density of defects and...

CuSCN has been widely considered a promising candidate for low-cost and high-stable hole transport material in perovskite semitransparent solar cells (STSCs). However, the low conductivity of the solution-processed CuSCN hole transport layer (HTL) hinders the hole extraction and transport in devices, which makes it hard to achieve devices with high performance. Herein, we report a facile additive engineering approach to optimize the p conductivity of CuSCN HTLs in perovskite STSCs. The n-butylammonium iodide additive facilitates the formation of Cu2+ and generates more Cu vacancies in the CuSCN HTL. This realizes a significant enhancement of the hole concentration and p conductivity of the film. Moreover, the additive improves the solubility of the CuSCN precursor solution and results in a uniform coverage on the perovskite active layer. Therefore, the perovskite STSC with a high power conversion efficiency (PCE) of 19.24% has been achieved, which is higher than that of the spiro-OMeTAD (18.83%) and CuSCN (17.45%) counterparts. In addition, the unencapsulated CuSCN-based device retains 87.5% of the initial PCE after 20 days in the ambient atmosphere.