The Role of Double Transport Layers on the Stability and Performance of Perovskite Solar Cells

As perovskites near the realm of commercialization, there are still so many unknowns about microscopic effects within the perovskite layer and within the overall device stack. In a typical PIN single junction perovskite solar cell, the hole transport layer (HTL) plays a critical role in serving as the template for which the perovskite crystalizes upon in addition to its intended job to extract the positively charged carriers. At this stage, there are a variety of material classes being used effectively in PIN solar cells including metal oxides, molecular layers and polymers. In this presentation, we will explore the role that these different classes of materials play in the function and stability of perovskite solar cells. In addition, the synergy of multiple HTLs can provide better extraction and stability. We will describe the interplay of double HTLs. On the top surface of the perovskite, passivation and the interface between perovskites and the fullerene are one of the weakest layers in the device design but also show the biggest potential for improvement. We explore stengthening strategies and alternative materials from the traditional C60/BCP combination.