High Members of the 2D Ruddlesden-Popper Halide Perovskites: Synthesis, Optical Properties, and Solar Cells of (CH3(CH2)3NH3)2(CH3NH3)4Pb5I16

• Published in: Chem Vol. 2; no. 3; pp. 427 - 440
• Main Authors: Stoumpos, Constantinos C., Soe, Chan Myae Myae, Tsai, Hsinhan, Nie, Wanyi, Blancon, Jean-Christophe, Cao, Duyen H., Liu, Fangze, Traoré, Boubacar, Katan, Claudine, Even, Jacky, Mohite, Aditya D., Kanatzidis, Mercouri G.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2017; Cell Press; Elsevier
• Subjects: Chemical Sciences; crystal structure; DFT calculations; halide perovskites; or physical chemistry; quantum wells; Ruddlesden-Popper perovskites; SDG7: Affordable and clean energy; solar cells; Theoretical and; Ruddlesden-Popper perovskites; quantum wells; crystal structure; halide perovskites; solar cells; SDG7: Affordable and clean energy; DFT calculations
• ISSN: 2451-9294; 2451-9294
• DOI: 10.1016/j.chempr.2017.02.004

Here, we present the fifth member (n = 5) of the Ruddlesden-Popper (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 family, which we successfully synthesized in high yield and purity. Phase purity could be clearly determined from its X-ray powder diffraction patterns, which feature the (0k0) Bragg reflections at low 2θ angles. The obtained pure n = 5 compound was confirmed to be a direct band-gap semiconductor with Eg = 1.83 eV. The direct nature of the band gap is supported by density functional theory calculations. Intense photoluminescence was observed at room temperature at 678 nm arising from the band edge of the material. High-quality thin films can be prepared by the hot-casting method from solutions with a pure-phase compound as a precursor. The planar solar cells fabricated with n = 5 thin films demonstrate excellent power-conversion efficiency of 8.71% with an impressive open-circuit voltage of ∼1 V. Our results point to the use of layered perovskites with higher n numbers and pure chemical composition. [Display omitted] •A 2D halide perovskite has been synthesized and structurally characterized•Direct-band-gap semiconductor with a multiple-quantum-well electronic structure•Narrows the gap between confined quantum wells and infinite extended lattices•Efficient solar cells have been fabricated by the hot-casting method Ruddlesden-Popper (RP) perovskites are cutting-edge materials in the field of hybrid halide perovskite semiconductors as second-generation systems for optoelectronic devices. We report on the synthesis and characterization of (CH3(CH2)3NH3)2(CH3NH3)4Pb5I16, which represents the fifth (n = 5) member of a homologous RP perovskite series. The orthorhombic material has a direct band gap Eg of 1.83 eV and exhibits room-temperature photoluminescence at 678 nm. Density functional theory calculations indicate that the compound has broad electronic bands with light effective masses for electron and hole carriers, comparable with those of the CH3NH3PbI3 (n = ∞) perovskite, resulting in high charge-carrier mobility required for planar opto-electronic device applications. We thus demonstrate highly stable planar solar cells fabricated with this material as a light absorber with a promising efficiency of 8.71%. The two-dimensional variety of the emerging semiconductor class of halide perovskites, the so-called Ruddlesden-Popper perovskites, feature as important players in the improvement of optoelectronic devices because of their environmental stability. The family is now extended to include its fifth homologous member, a five-layer-thick perovskite semiconductor with a direct band gap. The availability of this latest member paves the way for detailed physicochemical studies of its properties and allows exploration of its diverse applications.