Strain-durable dark current in near-infrared organic photodetectors for skin-conformal photoplethysmographic sensors

Hyeong Ju Eun; Hanbee Lee; Yeongseok Shim; Gyeong Uk Seo; Ah Young Lee; Jong Jin Park; Junseok Heo; Sungjun Park; Jong H Kim

doi:10.1016/j.isci.2022.104194

Strain-durable dark current in near-infrared organic photodetectors for skin-conformal photoplethysmographic sensors

iScience. 2022 Apr 4;25(5):104194. doi: 10.1016/j.isci.2022.104194. eCollection 2022 May 20.

Authors

Hyeong Ju Eun¹, Hanbee Lee², Yeongseok Shim², Gyeong Uk Seo¹, Ah Young Lee¹, Jong Jin Park¹, Junseok Heo², Sungjun Park², Jong H Kim¹

Affiliations

¹ Department of Molecular Science and Technology, Ajou University, Suwon 16449, Republic of Korea.
² Department of Electrical and Computer Engineering, Ajou University, Suwon 16499, Republic of Korea.

Abstract

Sensitive detection of near-infrared (NIR) light is applicable to variety of optical, chemical, and biomedical sensors. Of these diverse applications, NIR photodetectors have been used as a key component for photoplethysmography (PPG) sensors. In particular, because NIR organic photodetectors (OPDs) enable fabrication of stretchable and skin-conformal PPG sensors, they are attaining tremendously increasing interest in both academia and industry. Herein, we report strain-durable and highly sensitive NIR OPDs using an organic bulk heterojunction (BHJ) layer. For effective suppression of dark current, we employed BHJ combination consisting of PTB7-Th:Y6 which forms high energy barrier against transport-injected holes. The optimized OPDs exhibited high specific detectivity up to 2.2 × 10¹² Jones at 800 nm. By constructing the devices on the parylene substrates, we successfully demonstrated stretchable NIR OPDs and high-performance skin-conformal PPG sensors.

Keywords: Applied sciences; Sensor; Wearable computing.