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Autori principali: Ohara, Masahiro, Inoue, Taiyo, Tanaka, Yuya, Ishii, Hisao
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2512.06742
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author Ohara, Masahiro
Inoue, Taiyo
Tanaka, Yuya
Ishii, Hisao
author_facet Ohara, Masahiro
Inoue, Taiyo
Tanaka, Yuya
Ishii, Hisao
contents Understanding energy level alignment at organic interfaces is crucial for optimizing the performance of organic devices. Interface dipole and band bending significantly influence carrier recombination and generation mechanisms. A method of simulating energy level alignment at metal/organic and organic/organic interfaces by assuming a thermal equilibrium model has been proposed, but its validation against experimental methods is still limited. In this study, the work function change in the $α$-NPD/HAT-CN/Au interface was measured as a typical donor/acceptor system using a rotary Kelvin probe (RKP). Our findings demonstrate good agreement with simulations only at metal/organic interfaces which have "active" charge transfer. It is suggested that thermal equilibrium is not achieved simply by depositing the film under dark condition, and some treatment to supply carriers, such as exposure to UV light, is necessary for accurate evaluation. At the organic/organic interface, the the experimental results did not agree with thermal equilibrium model, highlighting the need to consider substrate-driven carrier supply and polarization effects when evaluating energy level alignment.
format Preprint
id arxiv_https___arxiv_org_abs_2512_06742
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Does Fermi Level Alignment Hold Across Organic Interfaces? -- An Investigation Using a Rotary Kelvin Probe
Ohara, Masahiro
Inoue, Taiyo
Tanaka, Yuya
Ishii, Hisao
Materials Science
Understanding energy level alignment at organic interfaces is crucial for optimizing the performance of organic devices. Interface dipole and band bending significantly influence carrier recombination and generation mechanisms. A method of simulating energy level alignment at metal/organic and organic/organic interfaces by assuming a thermal equilibrium model has been proposed, but its validation against experimental methods is still limited. In this study, the work function change in the $α$-NPD/HAT-CN/Au interface was measured as a typical donor/acceptor system using a rotary Kelvin probe (RKP). Our findings demonstrate good agreement with simulations only at metal/organic interfaces which have "active" charge transfer. It is suggested that thermal equilibrium is not achieved simply by depositing the film under dark condition, and some treatment to supply carriers, such as exposure to UV light, is necessary for accurate evaluation. At the organic/organic interface, the the experimental results did not agree with thermal equilibrium model, highlighting the need to consider substrate-driven carrier supply and polarization effects when evaluating energy level alignment.
title Does Fermi Level Alignment Hold Across Organic Interfaces? -- An Investigation Using a Rotary Kelvin Probe
topic Materials Science
url https://arxiv.org/abs/2512.06742