Improving the performance conversion efficiency of perovskite solar cells through optimization of charge transport layers: A review

The quest for environmentally friendly, clean, renewable, and sustainable energy is increasing daily, and perovskite solar cells are prominent candidates to unravel the quest. In recent years, many researchers have focused on perovskite solar cells and reported enhanced PCE in many of their studies. In addition, perovskite solar cells are easy to fabricate, cost-effective, and have fascinating electrical and optoelectronic properties, which make them a centre of focus for many researchers in the photovoltaic industry. Many researchers in the field of solar cells have turned their attention to hybrid organic/inorganic metal halide lead-free PSCs as a result of the rapid advancements in the previous ten years regarding the enhancement of PCE. The perovskite materials show a lot of advantages, such as longer carrier diffusion lengths and a wider-tunable bandgap, which results in a higher potential for light absorption, higher efficiency, and an easier cost of fabrication. All of these make perovskite solar cells a smart choice compared with Si-based and other types of solar cells. According to Roy et al., Afre and Pugliese, the efficiency of PSCs has seen a sharp increase from 3.5 % to more than 25.8 % in the last decade. This reported PCE value is still low and needs to be improved upon. Therefore, the main objective of this review is to improve the photovoltaic performance of perovskite solar cells, particularly the PCE. This necessitate having a good grasp of the overview of each of the perovskite solar cell components (the electrodes, the transport layers, and the absorber layers), their functions, and a whole lot of mechanisms responsible for the PCE increase as well as its stability as considered in this study. This review work thoroughly discusses four strategies to improve the photovoltaic performance of perovskite solar cells, particularly the PCE. The utilisation of supportive interface layers, charge transport layer optimization, fabrication processes, and diverse device architectural developments are examined. It was observed that the electronic and crystal structure, fabrication techniques, PSCs’ architectures, charge transport mechanisms, and supportive layers play vital roles in the optimization of the PCE, as well as its short-term and long-term stability. An insight into a new PSC research direction includes: interfacial modification techniques to enhanced PCE, the cost effectiveness of multilayered PSCs novelty for improved PCE of lead-free PSCs and other issues impeding PSCs from large-scale commercialisation and the actions needed to resolve them.