Facet-Dependent Control of PbI₂ Colloids for over 20% Efficient Perovskite Solar Cells

Abstract

Organic−inorganic hybrid perovskite-based solar cells (PSCs) have made impressive progress during the past few years, and record power conversion efficiency over 23% has been achieved. However, for solution-processed perovskite films, one of the major challenges for film quality improvement is the lack of a regulation strategy for the colloids in the precursor solution. Here, we demonstrate facet-dependent colloid engineering to adjust the quality of a perovskite film and its photovoltaic performance. This is realized by the development of a facet passivation strategy to synthesize PbI 2 (S-PbI 2 ) with tunable morphology. Further, facet-dependent PbI 2 colloid regulation is demonstrated, and the relations among the morphology of the PbI 2 crystal, features of PbI 2 colloids, the morphology of the PbI 2 film, and the photovoltaic performance of MAPbI 3 are established. The PSCs based on 10% S-PbI 2 exhibited a best PCE of 20.22% with improved device reproducibility and hysteresis index compared to that using commercial PbI 2 (∼18%).

Post‐Treatment Engineering of Vacuum‐Deposited Cs2NaBiI6 Double Perovskite Film for Enhanced Photovoltaic Performance

“…The optical property of Cs 2 NaBiI 6 films was characterized by UV–vis and photoluminescence (PL) spectra, as shown in Figure b. It should be noted that the Cs 2 NaBiI 6 film with no treatment shows higher intensity in the range of 550–650 nm, which is due to the light scattering effect of rough morphology of the film in the presence of holes . After introducing IPA soaking and DMF annealing, the typical exciton absorption peak of Cs 2 NaBiI 6 at ≈500 nm is enhanced.…”

Μethylammonium Chloride: A Key Additive for Highly Efficient, Stable, and Up‐Scalable Perovskite Solar Cells

“…[16] Nowadays, one can meet only few works on highly performing MAPbI 3 perovskites based on non-iodide lead precursor compounds. [23][24][25][26][27][28][29] These latest results were actually the motivation for us to write this review. To form a properly crystalline iodide or iodide/ bromide, perovskite and achieve high performance in solar cells, sources containing only iodide and bromide salts (PbI 2 , PbBr 2 , MAI, FAI, CsI, MABr) are typically used as precursor materials.…”

Fabrication of Sulfur‐Incorporated Bismuth‐Based Perovskite Solar Cells via a Vapor‐Assisted Solution Process

“…After the reaction time of 20 min, the coverage of the film was significantly improved (Figure S2b, Supporing Information). The morphology change was supposed to be the result of crystal expansion caused by the insertion of the MAI molecules into the Bi(xt) 3 decomposition product . After the reaction time for 30 min, the film morphology became uniform and dense, as shown in Figure c.…”