High Photovoltage of 1 V on a Steady-State Certified Hole Transport Layer-Free Perovskite Solar Cell by a Molten-Salt Approach

High Resolution Image Download MS PowerPoint Slide The determination of certified efficiency values for perovskite solar cells from current–voltage sweeps is under growing discussion. Here, we report for the first time a certified steady-state solar efficiency for a hole transport layer (HTL)-free perovskite cell of 12.6% measured continuously at maximum power point in an accredited laboratory. By applying a molten-salt-based MAPbI3 precursor solution, dense filling and improved perovskite crystallization inside the nanoporous graphite-based monolithic contact scaffold of the cell are achieved. A stabilized photovoltage as high as 1 V is achieved, representing the highest VOC reported for HTL-free MAPbI3-based devices. Charge transport properties are determined by switching from open- to short-circuit conditions. Strong and stable quenching of the photoluminescence indicates effective transportation and extraction of the photoexcited primary charge carriers. The existence of an efficient HTL-free device suggests that these cells are more of an n-p junction type than of n-i-p junction nature