An efficient post-treatment strategy with acetylacetone for low temperature CsPbI2Br solar cells.

• Acetylacetone as surface passivator enhance device performance. • Larger grains and less traps of CsPbI 2 Br films with AA treatment. • High efficiency and stable perovskite solar cells have been fabricated at low temperature (90 °C). All inorganic perovskite solar cells (PSCs) have been demonstrated to get tremendous interest recently owing to their better thermal stability. Nevertheless, some CsPbI 2 Br films prepared at low temperature have lower quality compared to those annealing at high temperature. Herein, to obtain high performance PSCs, a simple post-treatment strategy is presented by spin coating acetylacetone (AA) solution on the CsPbI 2 Br films. The AA treatment can reduce the density traps on the CsPbI 2 Br films surface and enlarge the size of grains, resulting in enhanced performance PSCs. After optimizing surface treatment, the devices based on low-temperature-processed CsPbI 2 Br with AA treatment achieved a power conversion efficiency (PCE) of 14.43%. The better CsPbI 2 Br films quality and interface contact of hole transport layer (HTL)/CsPbI 2 Br result in better device stability. Therefore, it could be a promising post treatment method for enhancing the performance of PSCs by introducing AA on the perovskite surface. [ABSTRACT FROM AUTHOR]