@article{WagnerWernerMiyamotoetal.2010,
  author    = {Wagner, Torsten and Werner, Frederik and Miyamoto, Ko-ichiro and Ackermann, Hans-Josef and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef},
  title     = {FPGA-based LAPS device for the flexible design of sensing sites on functional interfaces},
  series = {Physica Status Solidi (A). 207 (2010), H. 4},
  journal   = {Physica Status Solidi (A). 207 (2010), H. 4},
  isbn      = {1862-6300},
  pages     = {844 -- 849},
  year      = {2010},
  language  = {en}
}
@article{WernerWagnerYoshinobuetal.2013,
  author    = {Werner, Frederik and Wagner, Torsten and Yoshinobu, Tatsuo and Keusgen, Michael and Sch{\"o}ning, Michael Josef},
  title     = {Frequency behaviour of light-addressable potentiometric sensors},
  series = {Physica Status Solidi (A)},
  volume    = {210},
  journal   = {Physica Status Solidi (A)},
  number    = {5},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-396X ; 0031-8965},
  doi       = {10.1002/pssa.201200929},
  pages     = {884 -- 891},
  year      = {2013},
  abstract  = {Light-addressable potentiometric sensors (LAPS) are semiconductor-based potentiometric sensors, with the advantage to detect the concentration of a chemical species in a liquid solution above the sensor surface in a spatially resolved manner. The addressing is achieved by a modulated and focused light source illuminating the semiconductor and generating a concentration-depending photocurrent. This work introduces a LAPS set-up that is able to monitor the electrical impedance in addition to the photocurrent. The impedance spectra of a LAPS structure, with and without illumination, as well as the frequency behaviour of the LAPS measurement are investigated. The measurements are supported by electrical equivalent circuits to explain the impedance and the LAPS-frequency behaviour. The work investigates the influence of different parameters on the frequency behaviour of the LAPS. Furthermore, the phase shift of the photocurrent, the influence of the surface potential as well as the changes of the sensor impedance will be discussed.},
  language  = {en}
}
@article{WagnerMolinaYoshinobuetal.2007,
  author    = {Wagner, Torsten and Molina, Roberto and Yoshinobu, Tatsuo and Kloock, Joachim P. and Biselli, Manfred and Canzoneri, Michele and Schnitzler, Thomas and Sch{\"o}ning, Michael Josef},
  title     = {Handheld multi-channel LAPS device as a transducer platform for possible biological and chemical multi-sensor applications},
  series = {Electrochimica Acta. 53 (2007), H. 2},
  journal   = {Electrochimica Acta. 53 (2007), H. 2},
  isbn      = {0013-4686},
  pages     = {305 -- 311},
  year      = {2007},
  language  = {en}
}
@article{WernerWagnerMiyamotoetal.2012,
  author    = {Werner, Frederik and Wagner, Torsten and Miyamoto, Ko-ichiro and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef},
  title     = {High speed and high resolution chemical imaging based on a new type of OLED-LAPS set-up},
  series = {Sensors and Actuators B: Chemical},
  volume    = {175},
  journal   = {Sensors and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2011.12.102},
  pages     = {118 -- 122},
  year      = {2012},
  abstract  = {Light-addressable potentiometric sensors (LAPS) are field-effect-based sensors. A modulated light source is used to define the particular measurement spot to perform spatially resolved measurements of chemical species and to generate chemical images. In this work, an organic-LED (OLED) display has been chosen as a light source. This allows high measurement resolution and miniaturisation of the system. A new developed driving method for the OLED display optimised for LAPS-based measurements is demonstrated. The new method enables to define modulation frequencies between 1 kHz and 16 kHz and hence, reduces the measurement time of a chemical image by a factor of 40 compared to the traditional addressing of an OLED display.},
  language  = {en}
}
@article{WernerWagnerMiyamotoetal.2011,
  author    = {Werner, Frederik and Wagner, Torsten and Miyamoto, Ko-ichiro and Yoshinobu, Tatsuo and Sch{\"o}ning, Michael Josef},
  title     = {High speed and high resolution chemical imaging based on a new type of OLED-LAPS set-up},
  series = {Procedia Engineering. 25 (2011)},
  journal   = {Procedia Engineering. 25 (2011)},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {1877-7058},
  pages     = {346 -- 349},
  year      = {2011},
  language  = {en}
}
@article{MiyamotoItabashiWagneretal.2014,
  author    = {Miyamoto, Ko-ichiro and Itabashi, Akinori and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {High-speed chemical imaging inside a microfluidic channel},
  series = {Sensors and actuators. B: Chemical},
  volume    = {194},
  journal   = {Sensors and actuators. B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-3077 (E-Journal); 0925-4005 (Print)},
  doi       = {10.1016/j.snb.2013.12.090},
  pages     = {521 -- 527},
  year      = {2014},
  abstract  = {In this study, a high-speed chemical imaging system was developed for visualization of the interior of a microfluidic channel. A microfluidic channel was constructed on the sensor surface of the light-addressable potentiometric sensor (LAPS), on which the ion concentrations could be measured in parallel at up to 64 points illuminated by optical fibers. The temporal change of pH distribution inside the microfluidic channel was recorded at a maximum rate of 100 frames per second (fps). The high frame rate allowed visualization of moving interfaces and plugs in the channel even at a flow velocity of 111 mm/s, which suggests the feasibility of plug-based microfluidic devices for flow-injection analysis (FIA).},
  language  = {en}
}
@article{MiyamotoSugawaraKanohetal.2010,
  author    = {Miyamoto, Ko-ichiro and Sugawara, Yuri and Kanoh, Shin´ichiro and Yoshinobu, Tatsuo and Wagner, Torsten and Sch{\"o}ning, Michael Josef},
  title     = {Image correction method for the chemical imaging sensor},
  series = {Sensors and Actuators B: Chemical. 144 (2010), H. 2},
  journal   = {Sensors and Actuators B: Chemical. 144 (2010), H. 2},
  pages     = {344 -- 348},
  year      = {2010},
  language  = {en}
}
@article{MourzinaYoshinobuErmolenkoetal.2004,
  author    = {Mourzina, Ioulia G. and Yoshinobu, Tatsuo and Ermolenko, Yuri E. and Vlasov, Yuri G. and Sch{\"o}ning, Michael Josef and Iwasaki, H.},
  title     = {Immobilization of urease and cholinesterase on the surface of semiconductor transducer for the development of lightaddressable potentiometric sensors},
  series = {Microchimica Acta. 144 (2004), H. 1-3},
  journal   = {Microchimica Acta. 144 (2004), H. 1-3},
  isbn      = {0026-3672},
  pages     = {41 -- 50},
  year      = {2004},
  language  = {en}
}
@article{MiyamotoSekiSutoetal.2018,
  author    = {Miyamoto, Koichiro and Seki, Kosuke and Suto, Takeyuki and Werner, Frederik and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers},
  series = {Sensor and Actuators B: Chemical},
  volume    = {273},
  journal   = {Sensor and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2018.07.016},
  pages     = {1328 -- 1333},
  year      = {2018},
  abstract  = {The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.},
  language  = {en}
}
@article{WernerMiyamotoWagneretal.2017,
  author    = {Werner, Frederik and Miyamoto, Ko-ichiro and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Yoshinobu, Tatsuo},
  title     = {Lateral resolution enhancement of pulse-driven light-addressable potentiometric sensor},
  series = {Sensor and Actuators B: Chemical},
  volume    = {248},
  journal   = {Sensor and Actuators B: Chemical},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0925-4005},
  doi       = {10.1016/j.snb.2017.02.057},
  pages     = {961 -- 965},
  year      = {2017},
  abstract  = {To study chemical and biological processes, spatially resolved determination of the concentrations of one or more analyte species is of distinct interest. With a light-addressable potentiometric sensor (LAPS), chemical images can be created, which visualize the concentration distribution above the sensor plate. One important challenge is to achieve a good lateral resolution in order to detect events that take place in a small and limited region. LAPS utilizes a focused light spot to address the measurement region. By moving this light spot along the semiconductor sensor plate, the concentration distribution can be observed. In this study, we show that utilizing a pulse as light excitation instead of a traditionally used continuously modulated light excitation, the lateral resolution can be improved by a factor of 6 or more.},
  language  = {en}
}