Reducing Carrier Density in Formamidinium Tin Perovskites and Its Beneficial Effects on Stability and Efficiency of Perovskite Solar Cells

Seon Joo Lee, Seong Sik Shin, Jino Im, Tae Kyu Ahn, Jun Hong Noh, Nam Joong Jeon, Sang Il Seok, Jangwon Seo

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

In Sn-based halide perovskite solar cells (PSCs), the oxidation of Sn 2+ to Sn 4+ under ambient air leads to unwanted p-type doping in the perovskite film, which is a main reason for increased background carrier density and low efficiency. Here, we find that the introduction of bromide into formamidinium tin iodide (CH(NH 2 ) 2 SnI 3 , FASnI 3 ) lattice significantly lowers the carrier density of perovskite absorber, which is thought to be a result of reduction of Sn vacancies. It reduces the leakage current of devices, increases recombination lifetime, and finally improves open-circuit voltage and fill factor of the resulting devices employing mesoporous TiO 2 as an electron transport layer. Consequently, a high power conversion efficiency (PCE) of 5.5% is achieved with an average PCE of 5%, and after encapsulation the devices are highly stable over 1000 h under continuous one sun illumination including the ultraviolet region. This study suggests a simple approach for improving stability and efficiency in FASnI 3 -based PSCs.

Original languageEnglish
Pages (from-to)46-53
Number of pages8
JournalACS Energy Letters
Volume3
Issue number1
DOIs
Publication statusPublished - 2018 Jan 12

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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