D8.6 Performance differences of cells and modules fabricated under ambient conditions with those under N2 atmosphere

D8.6 Performance differences of cells and modules fabricated under ambient conditions with those under N₂ atmosphere

In this document, we report different processing routes tested to deposit the perovskite layer in nitrogen or in air with different relative humidity. The results show that according to the perovskite formulation and its crystallization method, the processing environment can have a relevant impact on the device performance. For example, in the 2-step hybrid process, the presence of oxygen is needed to achieve good device performance (> 10x efficiency improvement). Also, the impact of moisture appears negligible if the R.H. is properly controlled below a given threshold. Even if the threshold of R.H. needed to achieve efficient devices might change for different perovskite formulations and crystallization processes, it unlikely that an uncontrolled environment will not harm the reproducibility of the deposition and the device efficiency. For this reason, it will be recommended to have controlled processing environments for large area manufacturing, using dry air with a low relative humidity (i.e., < 20%). On the other hand, the use of pure nitrogen as a processing is not needed and not suggested as it will significantly increase operative costs and might even negatively impact device performance due to the lack of the passivation provided by oxygen.