High-Performance Photomultiplication Photodiode with a 70 nm-Thick Active Layer Assisted by IDIC as an Efficient Molecular Sensitizer

Deepan Kumar Neethipathi, Hwa Sook Ryu, Min Su Jang, Seongwon Yoon, Kyu Min Sim, Han Young Woo, Dae Sung Chung

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Here, a smart strategy for decreasing the active layer thickness of the organic photodiode down to 70 nm is demonstrated by utilizing a trap-assisted photomultiplication mechanism with the optimized chemical composition. Despite the presence of a high dark current, dramatically enhanced external quantum efficiency (EQE) via photomultiplication can allow significantly reduced active layer thickness, yielding high detectivity comparable to that of conventional Si. To achieve this, a spatially confined and electrically isolated optical sensitizer, 2,2′-((2Z,2′Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC) was introduced strategically between a hole transport active layer and a cathode. A nonfullerene acceptor, IDIC, turned out to be a much more efficient sensitizer than the conventional fullerene-based acceptors, as confirmed by the effective lowering of the Schottky barrier under illumination, as well as the highest EQE exceeding 130 000%. Due to its favorable electronic structure as well as two-dimensional molecular structure, a high detectivity over 1012 Jones was successfully demonstrated while maintaining the active layer thickness as 70 nm.

Original languageEnglish
Pages (from-to)21211-21217
Number of pages7
JournalACS Applied Materials and Interfaces
Volume11
Issue number23
DOIs
Publication statusPublished - 2019 Jun 12

Keywords

  • detectivity
  • external quantum efficiency
  • nonfullerene acceptor
  • photomultiplication
  • polymer photodetector

ASJC Scopus subject areas

  • Materials Science(all)

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