Inorganic metal oxides with the merits of high carrier transport capability, low cost and superior chemical stability have largely served as the hole transport layer (HTL) in perovskite solar cells (PSCs) in recent years. Among them, ternary metal oxides have gradually attracted attention because of the wide tenability of the two inequivalent cations in the lattice sites that offer interesting physicochemical properties. In this work, ZnCo₂O₄ nanoparticles (NPs) were prepared by a chemical precipitation method and served as the HTL in inverted PSCs. The device based on the ZnCo₂O₄ NPs HTL showed better efficiency of 12.31% and negligible hysteresis compared with the one using PEDOT:PSS film as the HTL. Moreover, the device sustained 85% of its initial efficiency after 240 h storage under a halogen lamps matrix exposure with an illumination intensity of 1000 W/m², providing a powerful strategy to design long term stable PSCs for future production.

We demonstrate regular-type perovskite solar cells based on vertically grown Ni-doped ZnO nanorod arrays and doped P3HT for solar energy harvesting. PCBM was introduced between Ni-doped ZnO nanorod arrays and the perovskite layer to improve electron extraction, while P3HT doped with bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI) was used as hole transporting layer. Three types of perovskite materials, including MAPbI₃, (MA)_x(FA)_1-xPbI₃, and (MA)_y(GA)_1-yPbI₃, were used as light harvesting layers to exploit conversion efficiency of photovoltaic devices. The optimized perovskite solar cell with the configuration of ITO/Ni-doped ZnO nanorods/PCBM/(MA)_y(GA)_1-yPbI₃/P3HT + Li-TFSI/Au revealed an open-circuit voltage of 0.83 V, a short-circuit current density of 23.73 mA/cm², a fill factor of 70%, and a power conversion efficiency of 13.79%.

In this work, we demonstrate a novel carrier transporting combination made of tungsten trioxide (WO3) nanomaterials and Cs2CO3/PCBM buffer bilayer for the fabrication of perovskite solar cells (PSCs). Two different types of WO3, including nanoparticles and nanorods, were prepared by sol-gel process and hydrothermal method, respectively. Cs2CO3/PCBM buffer bilayer was inserted between WO3 and perovskite layers to improve charge transfer efficiency and formation of pinhole-free perovskite layer. Besides, the leakage current of the devices containing Cs2CO3/PCBM buffer bilayer was significantly suppressed. The optimized device based on WO3 nanoparticles and Cs2CO3/PCBM bilayer showed an open-circuit voltage of 0.84 V, a short-circuit current density of 20.40 mA/cm2, a fill factor of 0.61, and a power conversion efficiency of 10.49 %, which were significantly higher than those of PSCs without Cs2CO3/PCBM buffer bilayer. The results revealed that the combination of WO3 nanomaterials and Cs2CO3/PCBM bilayer provides an effective solution for improving performances of PSCs.

The zinc oxide (ZnO) nanowire arrays on the indium tin oxide (ITO) glass substrates were fabricated by using the two-step hydrothermal method. A high transmittance ~92% of ZnO nanowire arrays on ITO substrate in the visible region was obtained. It was observed that the liquid crystal (LC) directors were aligned vertically to the (ZnO) nanowire arrays. The properties of ZnO nanowire arrays as vertical liquid crystal (LC) alignment layers and their applications for hybrid-aligned nematic LC modes were investigated in this work.

We report a novel fluorene-based polyelectrolyte carrying hexafluorophosphate counterions to dope into PCBM as an electron transporting layer (ETL).