Organic photodiode

This problem has attracted considerable attention, and intriguing results have been obtained. It would be important, however, to develop some applications in organic photodiodes, transistors, sensors, and charge-storage devices. 

Fig. 16.8. Image capturing with a photodiode matrix sheet in reflection geometry. Organic photodiodes distinguish between black and white from the different reflectivity of the black and white parts on the paper. This image-capturing device requires no optics or mechanical scanning device.

We have prepared the 8x8 organic photodiode matrix without organic transistors. The effective sensing area of each sensor cell is 50 x 50 pm2 and periodicity is 100 pm, which corresponds to 250 dpi. The dispersion of photocurrent of photodiodes with illumination of light (80 mW cm-2) is shown in Fig. 16.9 under light illumination of black and white areas. We have positioned a sheet of paper with a white capital letter T prepared by a laser printer on the photodiode matrix and measured the photocurrent of each detector with light illumination (80 mW cm-2). The mapping of photocurrents is shown in Fig. 16.9b. 

Internal and External Quantum Efficiencies of Organic Photodiodes... 

Someya, T., Kato, Y, Iba, S., Kawaguchi, H., and Sakurai, T., Integration of organic FETs with organic photodiodes for a large area, flexible, and lightweight sheet image scanners, IEEE Trans. Electron Devices, 52, 2502, 2005. 

The basic architectures which have been proposed for image sensing using organic semiconductors couple a single transistor per cell OFET architecture with an organic photodiode (Fig. 7.3 (a)) [142] or a photoconductor material such as titanyl pthalocyaninie (Fig. 7.3 (b)) [143]. These architectures allow the creation of fully additive photodetector elements on essentially arbitrary... 

Fig. 7.3. Two imager architectures addressed using OFETs (a) an organic photodiode as the light sensitive element, and (b) an organic photoconductor.

While we have demonstrated the successful application of our integrated organic photodiode-based test platform to antioxidant capacity determination, we regard this as a first step towards a universal platform for chemiluminescence-based testing at the point-of-care. To this end we have investigated the use of passive fluid delivery schemes (to circumvent the use of valves and external pumps) and the implementation of low-cost electronic read-out circuits (for both size and cost reduction). 

Figure 4.27 depicts a first demonstration system that comprises a microfluidic chip, an organic photodiode, and a low-cost printed circuit board (PCB) with amplifier. Powering and read-out is performed through a handheld computer. Future battery-driven devices are also envisaged to comprise an... 

Fig. 4.27. Picture of chemiluminescence demonstrator with integrated organic photodiode and low-cost electronics...

Hofmann, O., Miller, P, SuUivan, P., Jones, T.S., deMello, J.C., Bradley, D.D.C., and deMello, A.J., Thin-film organic photodiodes as integrated detectors for microscale chemiluminescence assays. Sensors and Actuators B—Chemical, 106, 878-884, 2005. 

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