Development of Thermal-Stable Hole Transport Layers for Highly Efficient and Stable Perovskite Solar Cells

This project aims to develop thermal-stable hole transporting layers for high-performance and stable perovskite solar cells. To achieve this, dopant-free organic materials (i.e. P3HT, CuPc, PCDTBT, X55 and the like) and inorganic materials (i.e. NiOx and its dopants) will be selected and optimizedfor useas hole transport layers (HTLs) in PSCs.

The project will build on our demonstration that the crystallinity of P3HT can be enhanced with the addition of graphene oxide, significantly boosting the conductivity by 2 orders of magnitudecompared to pristine P3HT films. A record stabilized efficiency of 17.8% (certified) for P3HT- and carbon-based (metal contact free) perovskite cells. We also demonstrated that these perovskite cells exhibit excellent ambient stability due to the hydrophobic nature of P3HT that caneffectively protect the perovskite active layer from moisture. It is well known from the organic electronics field that the morphology and crystallinityof semiconducting polymers such as P3HT affect the conductivity and surface work function, whichinturn can be controlled by the π-π stacking network of the polymer side-chains. This aspect of material optimization has not been fully exploited for perovskite solar cell applications. Therefore, itis valuable to carry out deeper characterization and process development research to realize thefull- potential of polymer HTLs.