Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
Publication date: 20th April 2022
Organic-inorganic halide perovskites have attracted strong attention from the photovoltaic research community since 2012, with power conversion efficiencies (PCE) already exceeding 27%. The low cost of perovskite precursors and their simple solution processability make them very promising to be developed as a next generation photovoltaic technology. However, perovskites are notoriously unstable, particularly in high humidity environments, which are currently slowing down their widespread implementation. While efficient encapsulation of the full device will certainly inhibit this type of degradation, it is still desirable to fabricate devices which are stable in standard atmospheric conditions. Here, the hole transporting materials (HTM) play a crucial role as they can enhance the stability of PSCs by acting as moisture barriers. In this work, the effect of a new hole transporting material composed of a functional amide backbone, termed TPABT, on device performance will be discussed. This material can be synthesised in a simple condensation reaction at an estimated cost of less than $5 per gram. Our results show that TPABT is able to outperform the state-of-the-art HTM, Spiro-OMeTAD, in some areas, such as reducing the cost of these devices and their stability over time. Particularly, the new HTM shows very high transparency in the visible range, increasing the potential short circuit current of devices in a tandem configuration with the a-Si solar cell. Although TPABT delivers high performing cells, it does not effectively protect the perovskite layer from degradation due to moisture ingress. Our results show, however, that the material exhibits excellent thermal stability with a degradation temperature close to 300°C.