Towards high performance perovskite solar cells: A review of morphological control and HTM development

The rapid improvements of perovskite solar cells since its inception has been associated the advancements in the perovskite layer itself and the efficiency of the hole transport materials (HTM). As a potential for future energy applications, recording high power conversion efficiency of perovskite solar cells has instigated the search for a more scalable production method with the usage of cheap and nontoxic precursors. By applying the insights from dye-sensitized solar cells fabrications methods, perovskite solar cells possess the ability to improve at a remarkable pace and the potential to be applied directly into the current systems without requiring new arrangements. Deposition of the perovskite layer onto the substrate has been a struggle particularly in the crystallinity, surface defects, toxicity and stability issues. Prerequisite to HTM includes high conductivity, diffusion length and compatibility with neighbouring layers. In this review paper, we will highlight two approaches that able to improve the perovskite solar cells performance namely crystallinity and morphological control of the perovskite and development of hole transporting materials for planar and inverted perovskite solar cells