Highly efficient photoelectron emission from stable low-work-function surfaces using organic bases

[Abstract]Photocathodes based on alkali metals such as cesium (Cs) exhibit high quantum efficiency (QE) owing to their low work functions (WFs). However, their poor stability and short lifetimes under vacuum conditions limit their practical application. In this study, we demonstrate that modifying electrodes with phenanthroline derivatives achieves ultra-low WFs of 2.2 eV while significantly enhancing stability compared to Cs under both high vacuum (~10−5 Pa) and ultra-high vacuum (~10−8 Pa) conditions. Notably, 4,7-bis(1-pyrrolidinyl)-1,10-phenanthroline exhibited greater stability than Cs and achieved more than twice the QE of Cs in the 2.7–3.5 eV photon energy range, without relying on negative electron affinity structures. These findings demonstrate the potential of organic low-WF materials as alternatives to alkali metals for photocathode applications, offering extended photoemission lifetimes under less stringent vacuum conditions.

https://opac.ll.chiba-u.jp/da/curator/900123370/

https://opac.ll.chiba-u.jp/da/curator/900123370/20250427_Tateno_APL_submit.pdf

Journal Article

Applied Physics Letters

126

24

2025-06-20

10.1063/5.0277925

author

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Applied Physics Letters 126, 241603 (2025) and may be found at https://doi.org/10.1063/5.0277925.