Photomultiplication Enabling High-Performance Narrowband Near-Infrared Organic Photodetectors

Continuous monitoring of food quality, blood oxygen, or industrial processes require high-throughput near-infrared photodetectors. Due to excellent properties like low-cost fabrication, flexibility and narrowband response, organic photodetectors (OPDs) have a huge market potential for such applications. An organic donor-acceptor blend with a low-energy and broad charge transfer (CT) feature is utilized, circumventing the difficulties of obtaining organic materials with significant absorption beyond 1000 nm. The increasing recombination of such low-energy gap materials that is detrimental for the quantum efficiency is overcome by applying two photocurrent multiplication (PM) mechanisms to the donor-acceptor blend. Combined with an optical micro-cavity, this OPD achieves a spectral response (SR) of 15 A W-1 at 1092 nm. With its spectrally narrow response of only 18 nm, this OPD technology can be used for highly resolved measurements. Contrary to OPDs working in the photovoltaic mode, this detector is optimized for operation under reverse bias. With its high spectral response, low-cost readout circuitry like CMOS can be used for signal detection.