Researchers at EPFL, Led by Wolfgang Tress, have traced the origin of apparently high and even negative capacitance values observed in perovskite solar cells. The team has found that the large perovskite capacitances are not classical capacitances in the sense of charge storage, but just appear as capacitances because of the cells’ slow response time.

perovskite solar cells seem to hold great potential, with their highly efficient and low-cost; However, issues like weak long-term stability remain a challenge. Related to this are peculiar phenomena occurring in perovskite materials and devices, where very slow microscopic processes can cause a “memory effect” of sorts.