Nano-structured CuO-Cu2O complex thin film-based perovskite solar cells were fabricated on an indium tin oxide (ITO)-coated glass and studied. Copper (Cu) thin films with a purity of 99.995 % were deposited on an ITO-coated glass by magnetron reactive sputtering. To optimize the properties of the nano-structured CuO-Cu2O complex thin films, the deposited Cu thin films were thermally oxidized at various temperatures from 300 to 400 °C. A CH3NH3PbI3 perovskite absorber was fabricated on top of CuO-Cu2O complex thin film by a one-step spin-coating process with a toluene washing treatment. Following optimization, the maximum power conversion efficiency (PCE) exceeded 8.1 %. Therefore, the low-cost, solution-processed, stable nano-structured CuO-Cu2O complex thin film can be used as an alternative hole transport layer (HTL) in industrially produced perovskite solar cells.

This study determines the effects of annealing treatment on the structure and the optical and electronic behaviors of the mixed (FAPbI₃)_1−x(MAPbBr₃)_x perovskite system. The experimental results reveal that (FAPbI₃)_1−x(MAPbBr₃)_x (x ~ 0.2) is an effective light-absorbing material for use in inverted planar perovskite solar cells owing to its large absorbance and tunable band gap. Therefore, good band-matching between the (FAPbI₃)_1−x(MAPbBr₃)_x and C₆₀ in photovoltaic devices can be controlled by annealing at various temperatures. Accordingly, an inverted mixed perovskite solar cell with a record efficiency of 12.0% under AM1.5G irradiation is realized.

This work presents mixed (FAPbI₃)_1−x(MAPbBr₃)_x perovskite films with various composition ratios, x (x = 0–1), which are formed using the spin coating method. The structural, optical, and electronic behaviors of the mixed (FAPbI₃)_1−x(MAPbBr₃)_x perovskite films are discussed. A device with structure glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/mixed perovskite/C₆₀/BCP/Ag was fabricated. The mixed perovskite film was an active light-harvesting layer. PEDOT:PSS was a hole transporting layer between the ITO and perovskite. Both C₆₀ and bathocuproine (BCP) were electron transporting layers. MAPbBr₃ was added to FAPbI₃ with a composition ratio of x = 0.2, stabilizing the perovskite phase, which exhibited a uniform and dense morphology. The optimal device exhibited band matching with C₆₀, resulting in a low series resistance (R_sh) and a high fill factor (FF). Therefore, the device with composition (FAPbI₃)_1−x(MAPbBr₃)_x and x = 0.2 exhibited outstanding performance.

We describe a method to enhance power conversion efficiency (PCE) of MAPbI₃ perovskite solar cell by inserting a FAPbX₃ perovskite quantum dots (QD-FAPbX₃) layer. The MAPbI₃ and QD-FAPbX₃ layers were prepared using a simple, rapid spin-coating method in a nitrogen-filled glove box. The solar cell structure consists of ITO/PEDOT:PSS/MAPbI₃/QD-FAPbX₃/C₆₀/Ag, where PEDOT:PSS, MAPbI₃, QD-FAPbX₃, and C₆₀ were used as the hole transport layer, light-absorbing layer, absorption enhance layer, and electron transport layer, respectively. The MAPbI₃/QD-FAPbX₃ solar cells exhibit a PCE of 7.59%, an open circuit voltage (Voc) of 0.9 V, a short-circuit current density (Jsc) of 17.4 mA/cm², and a fill factor (FF) of 48.6%, respectively.

In this study, the perovskite layers were prepared by two-step wet process with different CH3NH3I (MAI) concentrations. The cell structure was glass/FTO/TiO2-mesoporous/CH3NH3PbI3 (MAPbI3)/spiro-OMeTAD/Ag. The MAPbI3 perovskite films were prepared using high and low MAI concentrations in a two-step process. The perovskite films were optimized at different spin coating speed and different annealing temperatures to enhance the power conversion efficiency (PCE) of perovskite solar cells. The PCE of the resulting device based on the different perovskite morphologies was discussed. The PCE of the best cell was up to 17.42%, open circuit voltage of 0.97 V, short current density of 24.06 mA/cm2, and fill factor of 0.747.

In this work, a MAPbBr₃ quantum dot (QD-MAPbBr₃) layer was prepared by a simple and rapid method. Octylammonium bromide (OABr) gives the MAPbBr₃ better exciton binding energy, good surface morphology, and stability. To form a nanocrystalline thin film on indium tin oxide (ITO) glass, the QD-MAPbBr₃ film was coated by a spin-coating method in a nitrogen-filled glove box and the NiO_x film was used as an adhesive layer and hole transport layer. The highest transmittance of MAPbBr₃ on NiO_x/ITO glass was around 75% at 700 nm. This study also reported a high transparent and perovskite bulk-free ITO/NiO_x/QD-MAPbBr₃/C₆₀/Ag solar cell where the NiO_x, QD-MAPbBr₃, and C₆₀ were used as a hole transport layer, active layer, and electron transport layer, respectively.