Issue 43, 2020

Tuning the charge blocking layer to enhance photomultiplication in organic shortwave infrared photodetectors

Abstract

Emerging infrared photodetectors have reported a high level of gain using trap-assisted photomultiplication mechanisms enabling significant enhancements in their sensitivity. This work investigates a series of interfacial materials in order to understand how charge blocking layers facilitate trap-assisted photomultiplication in organic shortwave infrared detectors. The hole blocking layers induce accumulation of photogenerated holes at the interface, which in turn lowers the electron injection barrier and enables photomultiplication. In addition to examining photoresponse characteristics, the device dark current is analyzed by fitting to a charge injection model to quantify injection barriers. This demonstrates that the electric field induced barrier lowering effect plateaus with increasing applied bias. Among the interfaces studied, the best detectivity is observed using the hole blocking layer bathophenanthroline (Bphen), which reduces the probability of recombination and extends the lifetime of trapped holes to increase photomultiplication. This leads to a responsivity of 5.6 A W−1 (equivalent external quantum efficiency = 660% at 1050 nm) and detectivity of 109 Jones with broadband operation from 600 nm to 1400 nm.

Graphical abstract: Tuning the charge blocking layer to enhance photomultiplication in organic shortwave infrared photodetectors

Article information

Article type
Paper
Submitted
25 Kho 2020
Accepted
23 Maw 2020
First published
23 Maw 2020

J. Mater. Chem. C, 2020,8, 15142-15149

Author version available

Tuning the charge blocking layer to enhance photomultiplication in organic shortwave infrared photodetectors

N. Li, J. Lim, J. D. Azoulay and T. N. Ng, J. Mater. Chem. C, 2020, 8, 15142 DOI: 10.1039/D0TC03013A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements