Multi‐walled carbon nanotube‐assisted encapsulation approach for stable perovskite solar cells

Perovskite solar cells (PSCs) are regarded as the next‐generation thin‐film energy harvester, owing to their high performance. However, there is a lack of studies on their encapsulation technology, which is critical for resolving their shortcomings, such as their degradation by oxygen and moisture. It is determined that the moisture intrusion and the heat trapped within the encapsulating cover glass of PSCs influenced the operating stability of the devices. Therefore, we improved the moisture and oxygen barrier ability and heat releasing capability in the passivation of PSCs by adding multi‐walled carbon nanotubes to the epoxy resin used for encapsulation. The 0.5 wt% of carbon nanotube‐added resin‐based encapsulated PSCs exhibited a more stable operation with a ca. 30% efficiency decrease compared to the ca. 63% decrease in the reference devices over one week under continuous operation. Specifically, the short‐circuit current density and the fill factor, which are affected by moisture and oxygen‐driven degradation, as well as the open‐circuit voltage, which is affected by thermal damage, were higher for the multi‐walled carbon nanotube‐added encapsulated devices than the control devices, after the stability test.