| 초록 |
With the rapid growth of digital healthcare market, biometric imaging with NIR sensors have drawn a lot of attention for its simple but effective processing. Herein, we demonstrate a color-filter free NIR-selective organic photodetector through strategic designing of device architecture. With mixture of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PBDTTT-EFT) and poly(3-hexylthiophene-2,5-diyl) (P3HT) as photoactive donor layer (p-complex), and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) as acceptor layer, the device architecture is carefully designed so that the penetration depths of undesirable visible photons are efficiently isolated from the depletion region, while those of NIR photons are effectively overlapped. As a result, the fabricated device showed high specific detectivity (D*) of 1012 Jones solely within the NIR region. This is the first example of an organic NIR-selective photodetector that is realized by controlling the optical penetration depth and the length of depletion region rather than controlling the thickness of the active layer. |
