Authors Kublitski, J. ; Fischer, A. ; Xing, S. ; Baisinger, L. ; Bittrich, E. ; Spoltore, D. ; Benduhn, J. ; Vandewal, K. ; Leo, K.
Title Enhancing sub-bandgap external quantum efficiency by photomultiplication for narrowband organic near-infrared photodetectors
Date 26.08.2021
Number 59481
Abstract Detection of electromagnetic signals for applications such as health, product quality monitoring or astronomy requires highly responsive and wavelength selective devices. Photomultiplication-type organic photodetectors have been shown to achieve high quantum efficiencies mainly in the visible range. Much less research has been focused on realizing near-infrared narrowband devices. Here, we demonstrate fully vacuum-processed narrow- and broadband photomultiplication-type organic photodetectors. Devices are based on enhanced hole injection leading to a maximum external quantum efficiency of almost 2000% at -10·V for the broadband device. The photomultiplicative effect is also observed in the charge-transfer state absorption region. By making use of an optical cavity device architecture, we enhance the charge-transfer response and demonstrate a wavelength tunable narrowband photomultiplication-type organic photodetector with external quantum efficiencies superior to those of pin-devices. The presented concept can further improve the performance of photodetectors based on the absorption of charge-transfer states, which were so far limited by the low external quantum efficiency provided by these devices.
Publisher Nature Communications
Citation Nature Communications 12 (2021) 4259

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