Metal halide perovskite solar cells (PSCs) have attracted significant research attention in the past years and are regarded as a promising candidate for next-generation photovoltaic technology. This unprecedented surge in device performance is a testament to the extent to which PSCs upended the scientific knowledge of solution-processed photovoltaic devices. This remarkable success can largely be ascribed to a steadily improved device design, combined with optimization of the employed materials: from the first mesostructured configuration – a legacy of the evolution of PSCs from the work on dye-sensitized solar cells – to the planar thin-film design; and from the early methyl-ammonium lead iodide perovskite to the quadruple-cation mixed-halide perovskite.
PSCs can be fabricated either in the n‐i‐p or p‐i‐n device configuration; the first letter refers to which contact was deposited first, as sketched in Figure 1. Beyond nomenclature, the device configuration influences several physical properties. Therefore, at KPV-LAB we develop novel charge selective contacts and passivation techniques aiming high performance.
Figure 1. Schematic representation of n‐i‐p and p‐i‐n PSCs with a detailed view of the perovskite/ETL interface. (Source: Aydin, E., De Bastiani, M., De Wolf, S., Defect and Contact Passivation for Perovskite Solar Cells. Adv. Mater. 2019, 31, 1900428.)
Currently, KPV-LAB has focused on developing large-area compatible fabrication methods for high-performance solar cells using emerging hybrid perovskite material systems which include mixed cations and mixed halides. We majorly work on precursor-process-structure-property-performance relationship for hybrid lead halide perovskites, then translate these lessons into scalable processes, with the aim of achieving PCE > 25% and extended stability.
This study, which took place in Nature Energy, show that a lower bandgap perovskite than needed at standard test conditions is actually beneficial to perovskite/silicon tandem cells in the field.
This study demonstrates improved performance and stability via in-house synthesized organic cyano‐based π‐conjugated molecules. Kai Wang's this passivation study came out in Advanced Functional Materials.
This study, which came out in the recent issue of ACS Applied Materials & Interfaces, successfully demonstrates the Lewis-acid (TPFB) doping of the widely used spiro-OMeTAD hole transport materials for perovskite solar cells to. This dopant replaces the conventional LiTFSI/tBP doping. By doing so, the device stability is increased and processing is simplified.
This work, published in Solar RRL, presents a detailed study of the photophysics of multiple‐cation mixed halide lead perovskites and develops a concise picture of the impact of cesium/rubidium incorporation on the photophysics and device performance.
In collaboration with Carolin M. Sutter-Fella from Lawrence Berkeley National Laboratory
A comprehensive review on the passivation routes for perovskite solar cells toward the Shockley–Queisser limit.
This study unveils the potential of the room-temperature processed sputtered-NiOx hole transport layers for the single junction perovskites and perovskite-based tandem solar cells, specifically which has rough bottom cells.
Thanks to PMMA: PCBM Double-side passivation, very high‐efficiency (≈20.8%) perovskite cells with some of the highest open circuit voltages (1.22 V) reported for the same 1.6 eV bandgap are demonstrated.