posted on 2021-09-10, 14:35authored byPang Wang, Wei Li, Oskar J. Sandberg, Chuanhang Guo, Rui Sun, Hui Wang, Donghui Li, Huijun Zhang, Shili Cheng, Dan Liu, Jie Min, Ardalan Armin, Tao Wang
The
photovoltaic performance of inorganic perovskite solar cells
(PSCs) still lags behind the organic–inorganic hybrid PSCs
due to limited light absorption of wide bandgap CsPbI3‑xBrx under solar illumination. Constructing
tandem devices with organic solar cells can effectively extend light
absorption toward the long-wavelength region and reduce radiative
photovoltage loss. Herein, we utilize wide-bandgap CsPbI2Br semiconductor and narrow-bandgap PM6:Y6-BO blend to fabricate
perovskite/organic tandem solar cells with an efficiency of 21.1%
and a very small tandem open-circuit voltage loss of 0.06 V. We demonstrate
that the hole transport material of the interconnecting layers plays
a critical role in determining efficiency, with polyTPD being superior
to PBDB-T-Si and D18 due to its low parasitic absorption, sufficient
hole mobility and quasi-Ohmic contact to suppress charge accumulation
and voltage loss within the tandem device. These perovskite/organic
tandem devices also display superior storage, thermal and ultraviolet
stabilities.