Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV24)
DOI: https://doi.org/10.29363/nanoge.hopv.2024.101
Publication date: 6th February 2024
The use of a broad variety of additives (ranging from e.g. elemental ions to inorganic and organic molecular cations, neutral hydrophilic, hydrophobic or amphiphillic molecules and many more) that are supplemented during the growth of halide perovskite materials from solution or as a posteriori surface treatment, have often shown beneficial effects in improving both photoconversion efficiencies and long-term stability. Such additives can play a multitude of roles by e.g. leading to the formation of mixed 2D/3D perovskites, inducing a preferential phase stabilization (e.g. for the alpha perovskite phase of formamidinium lead halide over the delta-phase) or even catalyze phase conversion (e.g. from delta to alpha phase). They can also passivate surface point defects and grain boundaries and mediate or impede charge carrier transport between the perovskite material and the electron or the hole transporting layers . Moreover, they can also directly influence the nucleation and crystal growth process. The underlying atomistic mechanisms are only just starting to emerge and without mechanistic rationalization, the search of the vast available chemical space for optimal additives has to rely on a trial and error strategy.
During the last years, we have used a combination of different computational techniques to elucidate the manifold roles of different types of additives with the aim of establishing a fundamental mechanistic and possible universal structure-function relationships. In this talk, I will present some prototypical case studies that illustrate some of the possible atomistic impacts that additives can have and the corresponding descriptors that characterize their activities.