城戸・笹部・千葉研究室D3 鄭宇宏さん (Yu-Hong Cheng) と千葉貴之助教の2段階合成法を用いたスズ系ペロブスカイトLEDに関する論文がACS Applied Materials & Interfaces (IF: 9.229) に掲載されました！本成果は、山門先生・西辻先生との共著論文であり、DOSYおよびGIWAXS解析で大変お世話になりました！！
Two-Step Crystallization for Low-Oxidation Tin-Based Perovskite Light-Emitting Diodes
Yu-Hong Cheng, Reine Moriyama, Hinako Ebe, Kei Mizuguchi, Ryohei Yamakado, Shotaro Nishitsuji, Takayuki Chiba*, and Junji Kido*
Metal halide perovskites attract significant attention because of their excellent optoelectronic and semiconducting properties. However, there are environmental concerns related to the toxicity of the lead metal that is mainly used in these perovskites. PEA2SnI4 perovskite is a potential candidate for lead-free perovskites because of its pure red emission. Although, undesired Sn4+ oxidation results in the deterioration of PEA2SnI4 perovskite. We demonstrate the two-step crystallization of PEA2SnI4 through the (i) reprecipitation and (ii) recrystallization processes. A film prepared using this method exhibits narrowed emission, with a full width at half-maximum from 30.0 to 26.1 nm, because of its homogeneous emission. Moreover, the Sn4+ content of two-step-crystallized PEA2SnI4 films is five times lower than that of a control film. Diffusion-ordered spectroscopy analysis indicates that the two-step precursor exhibits a smaller hydrodynamic radius crystal seed, which enhances crystallization during spin coating. The resulting two-step crystallized PEA2SnI4-based light-emitting diode (LED) exhibits a maximum external quantum efficiency (EQE) of 0.4% with an average of 0.2%, which is two times greater than that of the control device. This two-step approach may be generalized to synthesize other lead-free materials.
城戸・笹部・千葉研究室HP : https://oled.yz.yamagata-u.ac.jp/view.cgi?p=400