Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films

Journal Article · Fri Sep 08 00:00:00 EDT 2017 · Journal of Visualized Experiments

DOI:https://doi.org/10.3791/55404· OSTI ID:1418307

Sutter-Fella, Carolin M. ^[1]; Li, Yanbo ^[2]; Cefarin, Nicola ^[3]; Buckley, Aya ^[4]; Ngo, Quynh Phuong ^[5]; Javey, Ali ^[6]; Sharp, Ian D. ^[7]; Toma, Francesca M. ^[7]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Chemical Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Electrical Engineering and Computer Sciences; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Chemical Sciences Division;; Univ. of Trieste (Italy). Dept. of Physics, Graduate School of Nanotechnology; Inst. Officina dei Materiali, Trieste (Italy). TASC Lab.
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Chemical Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
5. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis
6. Univ. of California, Berkeley, CA (United States). Dept. of Electrical Engineering and Computer Sciences; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
7. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Chemical Sciences Division

Organo-lead halide perovskites have recently attracted great interest for potential applications in thin-film photovoltaics and optoelectronics. Herein, we present a protocol for the fabrication of this material via the low-pressure vapor assisted solution process (LP-VASP) method, which yields ~19% power conversion efficiency in planar heterojunction perovskite solar cells. First, we report the synthesis of methylammonium iodide (CH₃NH₃I) and methylammonium bromide (CH₃NH₃Br) from methylamine and the corresponding halide acid (HI or HBr). Then, we describe the fabrication of pinhole-free, continuous methylammonium-lead halide perovskite (CH₃NH₃PbX₃ with X = I, Br, Cl and their mixture) films with the LP-VASP. This process is based on two steps: i) spin-coating of a homogenous layer of lead halide precursor onto a substrate, and ii) conversion of this layer to CH₃NH₃PbI_3-xBr_x by exposing the substrate to vapors of a mixture of CH₃NH₃I and CH₃NH₃Br at reduced pressure and 120 °C. Through slow diffusion of the methylammonium halide vapor into the lead halide precursor, we achieve slow and controlled growth of a continuous, pinhole-free perovskite film. The LP-VASP allows synthetic access to the full halide composition space in CH₃NH₃PbI_3-xBr_x with 0 ≤ x ≤ 3. Depending on the composition of the vapor phase, the bandgap can be tuned between 1.6 eV ≤ E_g ≤ 2.3 eV. In addition, by varying the composition of the halide precursor and of the vapor phase, we can also obtain CH₃NH₃PbI_3-xCl_x. Films obtained from the LP-VASP are reproducible, phase pure as confirmed by X-ray diffraction measurements, and show high photoluminescence quantum yield. The process does not require the use of a glovebox.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1418307
• Journal Information: Journal of Visualized Experiments, Vol. 2017, Issue 127; ISSN 1940-087X
• Publisher: MyJoVE Corp.
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Lead Halide Perovskite
Low-Pressure Vapor-Assisted Solution Process
Thin Film
Solar Cell
Methylammonium Halide Synthesis
Tunable Band Gap