  Operational stability of perovskite solar cells is remarkably influenced by
the device temperature, therefore, decreasing the interior temperature of the
device is one of the most effective approaches to prolong the service life.
Herein, we introduce the spontaneous radiative cooling effect into the
perovskite solar cell and amplified this effect via functional structure design
of a full-carbon electrode (F-CE). Firstly, with interface engineering, >19%
and >23% power conversion efficiencies of F-CE based inorganic CsPbI3 and
hybrid perovskite solar cells have been achieved, respectively, both of which
are the highest reported efficiencies based on carbon electrode and are
comparative to the results for metal electrodes. Highly efficient thermal
radiation of this F-CE can reduce the temperature of the operating cell by
about 10 {\deg}C. Compared with the conventional metal electrode-based control
cells, the operational stability of the above two types of cells have been
significantly improved due to this cooling effect. Especially, the CsPbI3 PSCs
exhibited no efficiency degradation after 2000 hours of continuous operational
tracking.
