It is well established that for organic photodetectors (OPDs) to compete with their inorganic counterparts, low dark currents at reverse bias must be achieved. Here, two rhodanine-terminated nonfullerene acceptors O-FBR and O-IDTBR are shown to deliver low dark currents at -2 V of 0.17 and 0.84 nA cm-2, respectively, when combined with the synthetically scalable polymer PTQ10 in OPD. These low dark currents contribute to the excellent sensitivity to low light of the detectors, reaching values of 0.57 μW cm-2 for PTQ10:O-FBR-based OPD and 2.12 μW cm-2 for PTQ10:O-IDTBR-based OPD. In both cases, this sensitivity exceeds that of a commercially available silicon photodiode. The responsivity of the PTQ10:O-FBR-based OPD of 0.34 AW-1 under a reverse bias of -2 V also exceeds that of a silicon photodiode. Meanwhile, the responsivity of the PTQ10:O-IDTBR of 0.03 AW-1 is limited by the energetic offset of the blend. The OPDs deliver high specific detectivities of 9.6 × 1012 Jones and 3.3 × 1011 Jones for O-FBR- and O-IDTBR-based blends, respectively. Both active layers are blade-coated in air, making them suitable for high-throughput methods. Finally, all three of the materials can be synthesized at low cost and on a large scale, making these blends good candidates for commercial OPD applications.
Bibliographical noteKAUST Repository Item: Exported on 2020-11-03
Acknowledged KAUST grant number(s): OSR- 2018-CARF/CCF3079, OSR-2015-CRG4-2572, OSR -4106 CPF2019.
Acknowledgements: GIWAXS experiments were performed at BL11 NCD-SWEET beamline at ALBA Synchrotron (Spain) with the collaboration of Dr Eduardo Solano. N.G. Acknowledges the Imperial College Research Fellowship Scheme. The authors acknowledge the funding from EC FP7 Project SC2 (610115), ECH2020 (643791), EPSRC Projects EP/G037515/1, EP/M005143/1, and EP/L016702/1 and from King Abdullah University of Science and Technology Office of Sponsored Research (OSR) under Award nos. OSR- 2018-CARF/CCF3079, OSR-2015-CRG4-2572, and OSR -4106 CPF2019.