High-efficiency perovskite tandem solar cells making use of cross-linked layers

• The power conversion performance (PCE) of single-junction perovskite solar cells (PSCs) has actually increased remarkably from 3.8% to 25.2% in simply a decade. As the quick development of PCE has been approaching the limit of its academic performance, making tandem solar cells by incorporating subcells with different bandgaps offers an avenue to surpass the Shockley-Queisser restrictions of single-junction solar cells.

The tandem gadgets make use of different parts of the solar ranges making use of subcells with various bandgaps to reduce the thermal loss of photo-generated providers. As a result of the tunable bandgap, high absorption coefficient and reduced manufacture price, metal halide perovskites are promising candidates for tandem tools.

However, the performance of perovskite-based tandem solar cells is largely restricted by wide-bandgap top-cells which commonly have a large open-circuit voltage (VOC) loss. The severe nonradiative charge recombination at the user interface between perovskite as well as opening transportation layer (HTL) is a vital aspect resulting in the big VOC loss.

Recently, study team of Prof. Hairen Tan from Nanjing College has utilized the cross-linked natural tiny molecule VNPB as the HTL for wide-bandgap perovskite solar cells. A VOC rise of nearly 50 mV was successfully acquired for wide-bandgap solar cells with bandgaps of 1.6 eV, 1.7 eV and 1.8 eV.

Compared to the control gadget making use of PTAA polymeric HTL, the perovskite movies deposited on VNPB have bigger grain size and also much better crystallinity. VNPB makes it possible for faster cost removal and also lowers problem density at the HTL/perovskite interface.

Density functional theory (DFT) computation reveals that the closer get in touch with in between VNPB and also perovskite increases the issue development power and decreases the problem density, thus effectively decreasing the non-radiative recombination of service providers. Finally, the PCEs of perovskite/perovskite and also perovskite/silicon tandem solar cells utilizing VNPB as HTL get to 24.9% and also 25.4%, specifically.

This work reveals that cross-linkable little molecules are promising for high-efficiency and cost-efficient perovskite tandem solar gadgets.