Wavelength-Selectivity of Organic Photoconductive Devices by Solution Process

Abstract

Organic photoconductive devices sensitive to blue, green, and red lights were achieved using poly(9,9-dioctylfluorenyl-2,7-diyl)-co-1,4benzo-(2,1,3)-thiadiazole (F8BT), rhodamine 6G-doped poly(9,9-dioctylfluorene) (PFO), nickel tetrakis(tert-butyl)phthalocyanine-doped PFO, respectively. These organic materials can be coated by a solution process, which leads us to realize the low fabrication cost and the large device area. Selectivity of spectral responses of these organic films were good enough to divide the incident light into three color components (blue, green, and red), indicating the possibility of a color separation without a prism for high resolution cameras. Quantum efficiencies of devices were estimated by absorption coefficients of photoconductive materials and photo-induced current densities while irradiating a visible light. The quantum efficiency of a blue sensitive device was better than those of green and red sensitive devices due to the suitable energy level of the blue sensitive material, F8BT.

Organic Photodiodes: The Future of Full Color Detection and Image Sensing

“…Fukuda et al [ 147 ] have developed a three-color sensor based on different organic materials with pixels that separately absorb blue, green and red light (see Figure 9 a(i)). The organic materials were initially selected by a simple screening of the literature and relatively simple OPDs (ITO/organic layer/Al) comprised of neat solution-processed fi lms were prepared.…”

“…The FWHM of the blue OPD was ≈120 nm (photocurrent) although the EQE was only 0.12% at -2.3 V due to it being a homojunction. [ 147 ] Indeed, homojunctions generally tend to give low EQEs. [ 216 ] When F8BT ( N1 ) was blended with various electronaccepting materials, the blue-sensitive OPD performance was improved.…”

Evaluation of Thin Film Surface Shape as a Function of Dispersant Concentration in Carbon Nanotube Thin Film Fabrication via the Electrospray Method

“…At present, indium tin oxide (ITO) is widely used for the main transparent electrode films in liquid crystal display panels and solar batteries made of organic electroluminescent materials, touch panels, flat panel displays, and so on [1][2][3][4][5][6]. However, indium, which is a rare metal, is expensive, and its supply is limited.…”

Ultrafast study of charge generation in silole:fluorene mixed film for color selective organic photoconductive device

“…A previous paper demonstrated superior color selectivity of solution-processed organic photoconductive devices at blue, green, and red regions [6]. A low carrier recombination probability in an organic layer is important factor for the efficient photo-excited carrier transport to electrodes.…”

“…By now, several research groups reported novel organic devices fabricated by solution processes, such as photovoltaic cells [1,2] and sensors [3]. In addition, color selective organic photoconductive devices have been attracting considerable attention for stacked organic image sensor instead of Sibased charge coupled devices and complementary metal oxide semiconductor sensors [4][5][6]. This is because absorption coefficients of several organic materials are higher than that of Si at a visible wavelength region.…”