Minireview and Perspectives of Liquid Crystals in Perovskite Solar Cells

The development of perovskite solar cells (PSCs) has gained attention with the ever increasing demand for energy conversion systems across the globe. In this context, utilization of certain liquid crystals (LCs) has been found to play a crucial role in enhancing the stability and efficiency of the PSC in the last 5 years. At this point, it is a high time to cover the recent achievements of LC molecules in the fabrication of PSC devices. Thus, the present review encompasses the introduction to LC and PSC, the effect of LC-based additives to perovskite precursors, the role of LC molecules in stabilizing and enhancing the efficiency of the PSCs, and the use of LC molecules as hole-transporting materials (HTMs) or as an additive to the HTMs. Further, all of these studies revealed that the functional group and conjugation present in the LC molecules as well as their phase transition behavior play a vital role in stabilizing and enhancing the efficiency of the PSCs. The addition of LCs in PSCs is one of among various emerging strategies that started recently, and we expect that this review can guide the researchers in selecting LC molecules for PSC applications to improve the stability and power conversion efficiency (PCE) of the device in the near future.