An ultra-sensitive colloidal quantum dot infrared photodiode exceeding 100 000% external quantum efficiency via photomultiplication

Byung Ku Jung, Taesung Park, Young Kyun Choi, Yong Min Lee, Tae Hyuk Kim, Bogyeom Seo, Seongkeun Oh, Jae Won Shim, Yu Hwa Lo, Tse Nga Ng, Soong Ju Oh

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, we present ultrasensitive infrared photodiodes based on PbS colloidal quantum dots (CQDs) using a double photomultiplication strategy that utilizes the accumulation of both electron and hole carriers. While electron accumulation was induced by ZnO trap states that were created by treatment in a humid atmosphere, hole accumulation was achieved using a long-chain ligand that increased the barrier to hole collection. Interestingly, we obtained the highest responsivity in photo-multiplicative devices with the long ligands, which contradicts the conventional belief that shorter ligands are more effective for optoelectronic devices. Using these two charge accumulation effects, we achieved an ultrasensitive detector with a responsivity above 7.84 × 102 A W−1 and an external quantum efficiency above 105% in the infrared region. We believe that the photomultiplication effect has great potential for surveillance systems, bioimaging, remote sensing, and quantum communication.

Original languageEnglish
Pages (from-to)487-494
Number of pages8
JournalNanoscale horizons
Volume9
Issue number3
DOIs
Publication statusPublished - 2024 Jan 15

Bibliographical note

Publisher Copyright:
© 2024 The Royal Society of Chemistry.

ASJC Scopus subject areas

  • General Materials Science

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