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Download fileReproducible, High Performance Fully Printed Photodiodes on Flexible Substrates through the Use of a Polyethylenimine Interlayer
journal contribution
posted on 2018-09-04, 00:00 authored by Matteo Cesarini, Biagio Brigante, Mario Caironi, Dario NataliThis
paper investigates with a statistical analysis the issue of performance
reproducibility and optimization in fully inkjet-printed organic photodetectors
on flexible substrates. The most crucial process step to obtain reproducible,
well performing devices with a high process yield turns out to be
the printing of the thin polyethylenimine interlayer used as a surface
modifier for the bottom electrode. Controlling solution composition
and deposition parameters for this layer, a 57 nA cm–2 mean reverse dark current was achieved, with an outstanding standard
deviation as low as 15 nA cm–2, with dramatic improvements
in process yield (from less than 20% to over 90%). Device performance
in terms of dark currents, EQE (from 50% up to 90% at 525 nm, depending
on process), and rectification (ratio between forward current and
reverse current over 104 and reaching 105 in
the best cases) is among the best for fully printed detectors. Furthermore,
the importance of relative humidity control in the deposition environment
during the interlayer printing on device characteristics is reported,
indicating the processing conditions optimal for scaling to mass manufacturing.
The overall interlayer optimization approach was applied to a process
using widely adopted materials in the organic optoelectronics field,
and thus retains relevance on a broad range.
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Keywords
525 nmPrinted PhotodiodesFlexible SubstratesControlling solution compositionprocess stepEQEdevice characteristicsmass manufacturinghumidity control10 510 4interlayer optimization approachpolyethylenimine interlayerprocessing conditionscmoptoelectronics fieldbottom electrodeHigh PerformancenAPolyethylenimine Interlayerdeposition environmentinterlayer printingdeposition parametersperformance reproducibilitysurface modifier