Bulk-Heterojunction Adjustment Enables a Self-filtering Organic Photodetector with a Narrowband Response

• Published in: ACS applied materials & interfaces Vol. 14; no. 33; pp. 38004 - 38012
• Main Authors: Tsai, Kuen-Wei, Madhaiyan, Govindasamy, Lai, Lai-Hung, Hsiao, Yu-Tang, Wu, Jhao-Lin, Liao, Chuang-Yi, Hou, Cheng-Hung, Shyue, Jing-Jong, Chang, Yi-Ming
• Format: Journal Article
• Language: English
• Published: American Chemical Society 24.08.2022
• Subjects: Organic Electronic Devices; organic photodetectors; organic imagers; organic photodiodes; organic image sensors
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c08336

Image-sensor technology is the foundation of many emerging applications, where the photodetector is designed to interact with incoming photons that have specific colors or wavelengths. A color filter is therefore crucial to enable the selective spectral response of the photodetector and to eliminate the crosstalk interference resulting from ambient lights. Unfortunately, a reduced detection sensitivity of the photodetector is inevitable due to an imperfect light filtering, which greatly limits the practical applications of selective-response photodetectors. Herein, we demonstrate a bulk-heterojunction (BHJ) organic composite featuring a self-filtering light responsive characteristic. Through a careful optimization of the BHJ film, the organic photodetector (OPD) demonstrates a high-selective spectral response to the infrared (IR) radiation without the need of applying a color filter. As a result, the self-filtering top-illuminated OPD exhibits a narrowband external quantum efficiency (EQE) of 53% with a narrow full width at half-maximum (fwhm) of 56 nm centering at 1080 nm. A high responsivity of 0.46 A W–1 is also achieved at 1080 nm wavelength due to the self-filtering characteristic.