Dual‐Functional Quantum Dot Seeding Growth of High‐Quality Air‐Processed CsPbI₂Br Film for Carbon‐Based Perovskite Solar Cells

Abstract

The high‐quality perovskite film is a prerequisite for high‐performance optoelectronic devices. Herein, CdSe colloidal quantum dots (QDs) serve as crystallization seeds for the first time to modulate the nucleation and crystal growth processes simultaneously of the CsPbI2Br film in the ambient environment. As additives, CdSe QDs help promote the nucleation process in the initial stage of perovskite formation. In addition, it is revealed that the surface ligands of QDs also have an essential influence on the subsequent crystal growth of the perovskite film. The bifunctional ligands on the surface of QDs are beneficial in delaying the growth process of perovskite due to the free functional groups at the ends. The CsPbI2Br film prepared with bifunctional organic ligand‐capped CdSe QD additives shows better crystallinity than that of the inorganic ligand‐based one due to the dual function of these kinds of QDs in not only promoting nucleation but also retarding crystal growth of CsPbI2Br crystals. As a result, the high‐quality CsPbI2Br film with a low defect state density is prepared in the ambient environment. The optimized efficiency of the assembled hole‐conductor‐free carbon‐based perovskite solar cells (C‐PSCs) is increased from 12.73% to 14.49%, which is one of the best results for all‐inorganic C‐PSCs.

All-Inorganic CsPb2I4Br/CsPbI2Br 2D/3D Bulk Heterojunction Boosting Carbon-Based CsPbI2Br Perovskite Solar Cells with an Efficiency of Over 15%

“…Therefore, reducing defects is a powerful tool to improve device performance. At this point, many efforts have been devoted to reducing defect states of inorganic perovskites, such as solvent engineering, additive engineering, − and doping strategy. ,− Besides, interface modification by inorganic salts or organic molecules is also an effective method to control the defect states of inorganic perovskites and improve the photovoltaic performance of the resultant PSCs. ,− However, there are still abundant defect states within the CsPbI 2 Br perovskite film, since V loss is still large. Therefore, a robust passivation strategy is needed to further reduce the nonradiative recombination loss in CsPbI 2 Br C-PSCs.…”

“…A hot-flow-assisted (HFA) spin-coating method was applied to prepare CsPbI 2 Br films in an ambient air atmosphere (RH = 30–70%). This method has been proven to be able to prepare high-quality CsPbI 2 Br films in the air. ,, The film prepared with a stoichiometric precursor solution is labeled as the control film henceforth. For the BHJ films, a nonstoichiometric precursor solution with excess PbI 2 (1–4%) was used.…”

Selection, Preparation and Application of Quantum Dots in Perovskite Solar Cells

“…For this reason, it is necessary to introduce QDs into the perovskite absorber layer to increase the size of the perovskite grains, reduce surface defects and the non-radiative recombination of carriers, which seems to be a practical and efficient method at present. Table 2 lists the details of the devices [ 16 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ].…”

Controllable Heterogenous Seeding‐Induced Crystallization for High‐Efficiency FAPbI3‐Based Perovskite Solar Cells Over 24%

“…[20] CdSe colloidal quantum dots were also reported to serve as crystallization seeds to modulate the nucleation and crystal growth processes. [21] Rather than directly adding the seed to the precursor, the formation of seed template at the bottom interface was also reported as an effective approach for the crystallization modulation. Gratzel's group reported a simple approach by using a predeposited poly(methyl methacrylate) (PMMA) template as the seeds to induce the growth of high-quality perovskite film.…”