Rationalizing long-lived photo-excited carriers in photocatalyst (La₅Ti₂CuS₅O₇) in terms of one-dimensional carrier transport

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• 作者：Yohichi Suzuki^a ; Rupashree Balia Singh^a ; Hiroyuki Matsuzaki^a ; Akihiro Furube^a ; ^d ; Guijun Ma^b ; ^c ; Takashi Hisatomi^b ; ^c ; Kazunari Domen^b ; ^c ; Kazuhiko Seki^a ; ^{k-seki@aist.go.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Photocatalyst ; Carrier dynamics ; Transient absorption ; One-dimensional carrier transport ; Diffusion
• 刊名：Chemical Physics
• 出版年：2016
• 出版时间：12 September 2016
• 年：2016
• 卷：476
• 期：Complete
• 页码：9-16
• 全文大小：726 K

文摘

The semiconductor La₅Ti₂CuS₅O₇ (LTC) is a potential photocatalyst capable of operating under visible light irradiation and behaves both as a photocathode and anode when embedded onto metal layers. Time-resolved diffuse reflectance (TRDR) measurements were carried out on LTC powder and LTC deposited on Au as the back contact using the particle-transfer method. Results of TRDR measurements of powdered LTC indicated the existence of long-lived photo-excited carriers, and suggested the existence of a mechanism for preventing carrier loss in LTC. Prior research has reported that LTC has a rod-shaped crystal structure and that electrons and holes are transported through different, spatially separated channels. Based on this, we introduced a one-dimensional carrier transport model. By analyzing TRDR data, we extracted material parameters such as the diffusion coefficient of LTC. Theoretical results indicated that a micron-sized LTC particle would be preferable if carriers trapped at the top-surface do contribute to photocatalytic gas generation.