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

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_1.2Br_1.8 perovskite films by introducing CuInSe₂ 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 CuInSe₂ 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.