Protecting hot carriers by tuning hybrid perovskite structures with alkali cations

Ti Wang; Linrui Jin; Juanita Hidalgo; Weibin Chu; Jordan M Snaider; Shibin Deng; Tong Zhu; Barry Lai; Oleg Prezhdo; Juan-Pablo Correa-Baena; Libai Huang

doi:10.1126/sciadv.abb1336

Protecting hot carriers by tuning hybrid perovskite structures with alkali cations

Sci Adv. 2020 Oct 23;6(43):eabb1336. doi: 10.1126/sciadv.abb1336. Print 2020 Oct.

Authors

Ti Wang^{1

2}, Linrui Jin¹, Juanita Hidalgo³, Weibin Chu⁴, Jordan M Snaider¹, Shibin Deng¹, Tong Zhu^{1

5}, Barry Lai⁶, Oleg Prezhdo⁴, Juan-Pablo Correa-Baena³, Libai Huang⁷

Affiliations

¹ Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
² School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China.
³ School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
⁴ Departments of Chemistry and Physics and Astronomy, University of Southern California, Los Angeles, CA 90007, USA.
⁵ Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Beijing 100081, China.
⁶ Advanced Photon Source, Argonne National Laboratory, 9700 Cass Ave., Lemont, IL 60439, USA.
⁷ Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA. libai-huang@purdue.edu.

Abstract

Successful implementation of hot carrier solar cells requires preserving high carrier temperature as carriers migrate through the active layer. Here, we demonstrated that addition of alkali cations in hybrid organic-inorganic lead halide perovskites led to substantially elevated carrier temperature, reduced threshold for phonon bottleneck, and enhanced hot carrier transport. The synergetic effects from the Rb, Cs, and K cations result in ~900 K increase in the effective carrier temperature at a carrier density around 10¹⁸ cm^-3 with an excitation 1.45 eV above the bandgap. In the doped thin films, the protected hot carriers migrate 100 s of nanometers longer than the undoped sample as imaged by ultrafast microscopy. We attributed these improvements to the relaxation of lattice strain and passivation of halide vacancies by alkali cations based on x-ray structural characterizations and first principles calculations.

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