Nucleation Regulation and Anchoring of Halide Ions in All‐Inorganic Perovskite Solar Cells Assisted by CuInSe2 Quantum Dots

Abstract Ionic feature of halide perovskites may lead to the formation of defect states in the polycrystalline films, which can deteriorate the device performance. To solve this issue, a low‐temperature seed‐assisted growth method can contribute to defect‐passivated CsPbI 1.2 Br 1.8 perovskite films by introducing CuInSe 2 quantum dots (QDs). As a result, the migration channels inside perovskite grains can be obviously suppressed, but few positive effects on the ions migration in grain boundaries. Conversely, this appearance demonstrate that the location of CuInSe 2 QDs is grain interior, but not grain boundary. Meanwhile, the lower defect density can help promoting device efficiency from 8.97% to 10.26%, which is among the high‐efficiency level. Besides, this work can also provide an in‐depth insight into the issue of photoinduced halide segregation.