Effect of the hole transporting layers on the inverted perovskite solar cells

Organic–inorganic hybrid perovskite solar cells have become one of the most promising photovoltaic technologies with conversion efficiency exceeding 25%. Increasing the efficiency of the perovskite solar cells is one of the most important challenges in the photovoltaic domain. The development of good hole transport layers (HTLs) is crucial for high-performance perovskite-based photovoltaic systems. Furthermore, it is important to accurately optimize the energy level matching between perovskites and hole transport materials via better charge collection. This work explores the effect of the HTLs on the growth process, morphology and crystallinity of the perovskite active layer and their impacts on the photovoltaic performance. Devices with planar inverted architecture ITO/HTL/MAPbI3-xClx/PC60BM/BCP/Ag were fabricated using a one-step deposition method. The effects of the use of various HTL materials and the effect of the thermal annealing treatment of this layer were investigated. Morphological and microstructural analyzes of the perovskite films were carried out by scanning electron microscopy, X-ray diffraction. The optical properties in particular the absorption and the recombination process were studied by UV–vis absorption spectroscopy and photoluminescence spectroscopy. The photoelectric properties were investigated by photocurrent–voltage characteristic curves.