Enhanced Dissociation of Hot Excitons with an Applied Electric Field under Low-Power Photoexcitation in Two-Dimensional Perovskite Quantum Wells

Vidya Kattoor; Kamlesh Awasthi; Efat Jokar; Eric Wei-Guang Diau; Nobuhiro Ohta

doi:10.1021/acs.jpclett.9b01759

Enhanced Dissociation of Hot Excitons with an Applied Electric Field under Low-Power Photoexcitation in Two-Dimensional Perovskite Quantum Wells

J Phys Chem Lett. 2019 Aug 15;10(16):4752-4757. doi: 10.1021/acs.jpclett.9b01759. Epub 2019 Aug 7.

Authors

Vidya Kattoor^{1

2}, Kamlesh Awasthi¹, Efat Jokar¹, Eric Wei-Guang Diau^{1

3}, Nobuhiro Ohta^{1

3}

Affiliations

¹ Department of Applied Chemistry and Institute of Molecular Science , National Chiao Tung University , 1001 Ta-Hsueh Road , Hsinchu 30010 , Taiwan.
² Sustainable Chemical Science and Technology (SCST) , Taiwan International Graduate Program (TIGP), Academia Sinica , Nankang, Taipei 115 , Taiwan.
³ Center for Emergent Functional Matter Science , National Chiao Tung University , 1001 Ta-Hsueh Road , Hsinchu 30010 , Taiwan.

PMID: 31379171
DOI: 10.1021/acs.jpclett.9b01759

Abstract

The dependence of photoluminescence (PL) on excitation power and the effect of an external electric field have been studied for a two-dimensional (2D) perovskite (C₄H₉NH₃)₂PbI₄ thin-film sample. The efficiency of dissociation of hot excitons to produce free carriers was enhanced with a small excitation power because the relaxation of hot excitons to cold emissive excitons was slow, indicating that the thermal energies of hot carriers can be utilized in solar cells under weak photoirradiation. The dissociation was notably enhanced with an applied electric field, resulting in efficient field-induced quenching of the PL. The present results shed light on an application of 2D perovskite materials to photovoltaic (PV) devices with dim radiation, e.g., for indoor PV applications; the concept of electric field-assisted solar cells might be applicable to next-generation solar cells.