Noise and detectivity limits in organic shortwave infrared photodiodes with low disorder

• DOI: 10.1038/s41528-020-0069-x
• Publication Date: 2020-04-29T10:03:17Z
• Authors: Zhenghui Wu; Ning Li; Naresh Eedugurala; Jason D. Azoulay; Dong-Seok Leem; Tse Nga Ng
• Keywords: Photodiode; Specific detectivity; Johnson–Nyquist noise

Abstract To achieve high detectivity in infrared detectors, it is critical to reduce the device noise. However, for non-crystalline semiconductors, an essential framework missing understand and predict effects of disorder on dark current. This report presents experimental modeling studies noise current exemplar organic bulk heterojunction photodiodes, with 10 donor–acceptor combinations spanning wavelength between 800 1600 nm. A significant reduction higher were found devices using non-fullerene acceptors (NFAs) comparison those fullerene derivatives. The low NFA blends was attributed a sharp drop off distribution bandtail states, as revealed by variable-temperature density-of-states measurements. Taking into account, we developed general physical model explain dependence thermal effective bandgap spread. provides theoretical targets maximum that can be obtained at different detection wavelengths inherently disordered photodiodes.