5 years ago

Minute-Scale Degradation and Shift of Valence-Band Maxima of (CH3NH3)SnI3 and HC(NH2)2SnI3 Perovskites upon Air Exposure

Minute-Scale Degradation and Shift of Valence-Band Maxima of (CH3NH3)SnI3 and HC(NH2)2SnI3 Perovskites upon Air Exposure
Akinori Saeki, Yukie Katsuki, Naoki Ishida, Atsushi Wakamiya, Ryosuke Nishikubo
The development of lead-free, tin-based perovskite solar cells is becoming a pervasive topic; however, the inherent instabilities of such cells have prevented a boost of their power conversion efficiency and a deeper understanding of their fundamental properties. By using the photoelectron yield spectroscopy (PYS) and flash-photolysis time-resolved microwave conductivity (TRMC) techniques, we investigate the effects of air exposure on the valence-band maxima (VBMs) and photoconductivities of tin iodide perovskites (methylammonium cation, MASnI3; formamidinium cation, FASnI3). These perovskites exhibit a shift of the VBM (e.g., from −5.02 eV at 0 min to −5.17 eV at 18 min), deterioration of the PYS profiles, and progressive decrease of the TRMC transients on the minute scale of air exposure. The addition of SnF2 was found to suppress the initial defect-related density of the filled electronic states of MASnI3 and FASnI3, as revealed by PYS, and to partly mitigate the degradation of MASnI3, as revealed by TRMC. A low-dimensional perovskite (MA2SnI6) composed of the oxidized form of Sn(IV) was also evaluated to explain the anomalous TRMC behavior of the air-exposed MASnI3. Our results provide an important basis for correlation with the degradation and energetics of a device.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b06294

DOI: 10.1021/acs.jpcc.7b06294

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.