Direct transfer patterning on three dimensionally deformed surfaces at micrometer resolutions and its application to hemispherical focal plane detector arrays

Abstract

Formation of high performance organic electronic devices on three dimensionally deformed surfaces is severely constrained by the tensile stresses and shear that are introduced during the deformation process. Here, we overcome these limitations to demonstrate the direct transfer of unstrained metals via cold welding onto preformed, 1.0 cm radius plastic hemispheres with micrometer scale feature resolutions to realize 10 kilopixel organic photodetector focal plane arrays (FPAs) that mimic the size, function, and architecture of the human eye. The passive matrix FPA consists of (40 μm) 2 organic double heterojunction photodetectors with response extending across the visible spectrum. The detector dark current density is 5.3 ± 0.2 μA/cm 2 at −1 V bias, and with a peak external quantum efficiency of 12.6 ± 0.3% at a wavelength of 640 nm. The photodetector impulse response was 20 ± 2 ns, making the FPA suitable for video recording applications. The measured dynamic range allows for 7 bit image resolution, and the FPA is used to create a simple image. This demonstration significantly extends the ability to transfer active electronic devices that has previously only been demonstrated on planar substrates.