Multiple-exciton generation (MEG) represents an effective strategy to break the Shockley-Queisser (SQ) limit, thereby enhancing the efficiency of photon-to-electron conversion. Here, we investigate MEG in monolayer MoTe, with an energy threshold of 2.22 eV (∼2.02) and a MEG conversion efficiency of 90%. We discuss the potential origins of efficient MEG in MoTe/WSe type I heterostructures, with a particular focus on the competition between MEG and hot-carrier extraction. We conclude that impact ionization is likely responsible for exciton multiplication. Our results suggest that monolayer MoTe has significant potential for efficient light harvesting and hot-carrier devices.
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http://dx.doi.org/10.1021/acs.jpclett.4c02784 | DOI Listing |
Adv Sci (Weinh)
February 2025
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Yuseong-Gu, 34141, Republic of Korea.
Plasmonic hot carriers have garnered considerable attention in photovoltaics and photocatalysis, yet their full potential is limited by the challenge of harvesting both positive and negative polarity hot carriers at the same time. Here, an unprecedented plasmonic hot carrier device capable of extracting both types of hot carriers simultaneously is demonstrated. This scheme involves generating and harnessing plasmonic hot electrons and holes concurrently using a lateral Si p-n junction diode coupled to Ag nanoprisms.
View Article and Find Full Text PDFJ Phys Chem Lett
February 2025
State Key Laboratory of Extreme Photonics and Instrumentation, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China.
Multiple-exciton generation (MEG) represents an effective strategy to break the Shockley-Queisser (SQ) limit, thereby enhancing the efficiency of photon-to-electron conversion. Here, we investigate MEG in monolayer MoTe, with an energy threshold of 2.22 eV (∼2.
View Article and Find Full Text PDFNano Lett
February 2025
Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
Harvesting of plasmon-induced hot carriers at the metal/semiconductor interface offers a promising and innovative avenue for solar energy conversion. However, their practical implementation is often hampered by their limited efficiencies. Herein, we have demonstrated a highly efficient plasmonic hot electron transfer with a quantum efficiency (QE) of up to 57 ± 4% from 5.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Physics, Pusan National University, Busan 46241, Republic of Korea.
Metal electrode deposition is universally adopted in the community for optoelectronic device fabrication, inducing hybridization at electrode interfaces, and allows efficient extraction or injection of photocarriers. However, hybridization-induced midgap states increase photocarrier recombination pathways, creating a paradoxical trade-off. Here, we discovered that efficient photocarrier extraction and a long photocarrier lifetime can be achieved simultaneously in MoS/van der Waals Au contact, minimizing photocarrier loss at the interface.
View Article and Find Full Text PDFAdv Mater
February 2025
Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, Kowloon, China.
Hot-carrier relaxation above the bandgap results in significant energy losses, making the extraction of hot carriers a critical challenge for efficient hot-carrier photocurrent generation in devices. In this study, we observe long-lived hot carriers in the metal-halide perovskite multiple quantum wells, (BA)(MA)PbI (n = 3), and demonstrate effective hot-hole photocurrent generation using 2D MoS₂ as an extraction layer. A high external quantum efficiency of short-circuit hot-carrier photocurrent of up to 35.
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