Science News: 2022 Joule, Achieve 20.32% PCE! How the Bulk Heterojunction Structure Can Do It
The open-circuit voltage (VOC) of cesium-based perovskite solar cells (Cs-PSCs) is severely limited by carrier recombination both in bulk and at the interface between the perovskite layer, which mainly from the increase in fabrication temperature. To improve the performance of Cs-PSCs, enhancing the quality of perovskite film and optimizing the device structure are effective strategies. Joule (IF 41.248) published a study in March 2022. Herein, the VOC is significantly promoted by constructing CsPbI3/Cs1-xDMAxPbI3 bulk heterojunction (BHJ) structure that was spontaneously formed through a precisely controlled spatially selective phase transition approach.
It is found that the perovskite BHJ structure not only facilitates the charge separation and collection process by increasing the built-in potential, but also significantly reduces the carrier recombination loss. Importantly, a maximum VOC of 1.23 V was obtained due to under-VOC reduction to 0.45V. and the champion power conversion efficiency (PCE) reached 20.32% (certified PCE of 19.66%). This study shows that junction engineering will become a new strategy for high-efficiency perovskite devices.
To summarize this research:
- The BHJ structure is helpful for the charge separation and collection process
- The maximum VOC of 1.23 V can be obtained when the VOC deficit is insufficient to 0.45V
- The BHJ device achieved the champion PCE of 20.32% (certified PCE of 19.66%)