Realizing Efficient and Reproducible Lead-free Perovskite Solar Cells with Purified Precursor Materials and Modified Solution Process

Jiewei Liu^a, Masashi Ozaki^a, Shinya Yakumaru^a, Taketo Handa^a, Ryosuke Nishikubo^b, Yoshihiko Kanemitsu^a, Akinori Saeki^b, Yasujiro Murata^a, Richard Murdey^a, Atsushi Wakamiya^a

^aKyoto University, Japan, Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan

^bOsaka University, Japan, FRC, 2-1Yamada-oka,, Suita, 565, Japan

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)

Kyōto-shi, Japan, 2019 January 27th - 29th

Organizers: Hideo Ohkita, Atsushi Wakamiya and Mohammad Nazeeruddin

Oral, Jiewei Liu, presentation 042
DOI: https://doi.org/10.29363/nanoge.iperop.2019.042
Publication date: 23rd October 2018

Organic-inorganic hybrid halide perovskites are promising photovoltaic (PV) materials with power conversion efficiencies (PCE) exceeding 23%. Although the toxic lead-based perovskite materials used in the leading perovskite solar cells (PSCs) are a significant impediment to commercialization, obtaining comparable performance using more environmentally friendly metals in place of lead has proven challenging. We are looking at Sn as a replacement for Pb, addressing key issues potentially holding back performance such as reagent purity and film morphology. The higher reactivity of SnI₂ compared to PbI₂ places additional importance on the purity of the reagents, and in the present work our perovskite films were fabricated from tin perovskite precursor materials such as solvent-coordinated tin halide complexes e.g. [SnI₂(dmf)] (Figure 1a)[1] which we confirmed to have significantly higher purity than commercially available SnI₂. The growth of smooth, high coverage perovskite films with high crystallinity is also important for high efficiency PSCs and we confirm that Sn-based perovskite films require modified fabrication methods compared to their lead analogs. We have developed two simple methods to improve tin halide perovskite film quality.[2] First, a hot antisolvent treatment (HAT) was found to increase the film coverage and prevent electric shunting in the photovoltaic device. Second, a solvent vapor annealing (SVA) step was noted to increase the average crystallite size. Both the morphology and the electrical properties of the perovskite films are improved as a result of the combined treatments, facilitating the fabrication of Sn-based perovskite solar cell devices with power conversion efficiencies of over 7% (Figure 1b).

References:

[1] Ozaki, M.; Katsuki, Y.; Liu, J.; Handa, T.; Nishikubo, R.; Yakumaru, S.; Hashikawa, Y.; Murata, Y.; Saito, T.; Shimakawa, Y.; et al. Solvent-Coordinated Tin Halide Complexes as Purified Precursors for Tin-Based Perovskites. ACS Omega 2017, 2 (10), 7016–7021.

[2] Liu, J.; Ozaki, M.; Yakumaru, S.; Handa, T.; Nishikubo, R.; Kanemitsu, Y.; Saeki, A.; Murata, Y.; Murdey, R.; Wakamiya, A. Lead-Free Solar Cells Based on Tin Halide Perovskite Films with High Coverage and Improved Aggregation. Angew. Chem., Int. Ed. 2018, 57 (40), 13221–13225.

Acknowledgements:

This work was supported by JST-ALCA (JPMJAL1603), COI, ERATO (JPMJER1302), and NEDO.

nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.

MATSUS

Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.

International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics

The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.