Proceedings of 13th Conference on Hybrid and Organic Photovoltaics (HOPV21)
Publication date: 11th May 2021
Carbon based perovskite solar cells (C-PSCs) are an attractive concept that allows promising results in terms of performance and stability of perovskite devices without having recourse to expensive hole transporting layers (HTL), namely Spiro-OMeTAD, a p-type material generally used by state-of-the-art perovskite-based devices. However, the absence of an HTL hinders the performance of the C-PSCs mainly perceived in the lower fill factor (FF) values obtained, which is an important indication of the performance and quality of solar cell devices. This work reports on a certified world record efficiency of 15.5% for hole selective layer (HSL) free printed carbon-electrode based perovskite solar cell, it also reports on a world record fill factor of 78.8% obtained through the certified measurements, which approaches the highest values reported in metal based electrode devices employing highly selective HSLs. The impact of the non-radiative recombination and resistivity losses on the fill factor (FF) of solar devices was investigated. We find only 3%abs loss due to non-radiative recombination with respect to the FF in the radiative limit of 90%, which can be attributed to an optimal diode ideality factor approaching 1.0. Moreover, contributions of shunt resistive losses are found to be negligible. We also discuss the theoretical physical constraints on the FF and examine its maximum obtainable potential.
This work was partially funded by the project UNIQUE, supported under the umbrella of SOLARERA.NET. Cofunded by ANR, PtJ, MIUR, MINECOAEI, and SWEA. SOLAR-ERA.NET was supported by the European Commission within the EU Framework Programme for Research and Innovation HORIZON 2020 (Cofund ERA-NET Action, no. 691664).
S. Z. gratefully acknowledges the Ph.D. scholarship support of the German academic exchange service (DAAD).