4.8 Article

A Molecular-Switch-Embedded Organic Photodiode for Capturing Images against Strong Backlight

Journal

ADVANCED MATERIALS
Volume 34, Issue 17, Pages -

Publisher

WILEY-V C H VERLAG GMBH
DOI: 10.1002/adma.202200526

Keywords

color-selectivity; diarylethene; image sensors; molecular switches; organic photodiodes

Funding

  1. Samsung Research Funding & Incubation Center of Samsung Electronics [SRFC-TA1803-01]

Ask authors/readers for more resources

This study proposes a method to overcome early photocurrent saturation in organic photodiodes (OPDs) by introducing a light-intensity-dependent transition of the operation mode. By doping the photoactive layer with a molecular switch, the proposed OPD exhibits high external quantum efficiency under low-intensity and high-intensity light illuminations, extending the photoresponse linearity to a higher light intensity.
When the intensity of the incident light increases, the photocurrents of organic photodiodes (OPDs) exhibit relatively early saturation, due to which OPDs cannot easily detect objects against strong backlights, such as sunlight. In this study, this problem is addressed by introducing a light-intensity-dependent transition of the operation mode, such that the operation mode of the OPD autonomously changes to overcome early photocurrent saturation as the incident light intensity passes the threshold intensity. The photoactive layer is doped with a strategically designed and synthesized molecular switch, 1,2-bis-(2-methyl-5-(4-cyanobiphenyl)-3-thienyl)tetrafluorobenzene (DAB). The proposed OPD exhibits a typical OPD performance with an external quantum efficiency (EQE) of 100% under low-intensity and high-intensity light illuminations, respectively, thereby resulting in an extension of the photoresponse linearity to a light intensity of 434 mW cm(-2). This unique and reversible transition of the operation mode can be explained by the unbalanced quantum yield of photocyclization/photocycloreversion of the molecular switch. The details of the operation mechanism are discussed in conjunction with various photophysical analyses. Furthermore, they establish a prototype image sensor with an array of molecular-switch-embedded OPD pixels to demonstrate their extremely high sensitivity against strong light illumination.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.8
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available