Browsing by Author "Lu, Chia-Jung"

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A low-cost miniaturized colorimetric sensor with vertically-stacked semi-transparent finger-type organic photo detector for formaldehyde sensing
(2019-10-01)
Lin, Ching-Fu
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Zan, Hsiao-Wen
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Lu, Chia-Jung
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Meng, Hsin-Fei
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Soppera, Olivier
We proposed a sensitive colorimetric sensing system using a paper-like sensing layer on top of a vertically stacked finger-type organic photodetector (OPD) and commercial light-emitting diode (LED). The stacked OPD/LED device was small, with an area of 0.8 cm x 0.5 cm that was even smaller than a coin. Using commercial colorimetric formaldehyde (HCHO) sensing molecules to form the sensing layer, the stacked detecting system successfully detected HCHO of concentrations ranging from 40 to 1000 ppb within 20 min. Critical parameters affecting the sensitivity were investigated. The final system exhibited a stable calibration curve over 60 days. The long lifetime was attributed to using 2,6-Bis(trimethyltin)-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b']dithiophene (PBDTTT-C-T): phenyl-C71-butyric acid methyl ester (PC71 BM) to serve as a blended system and using the current variation ratio to represent the sensing response.
A Versatile Method to Enhance the Operational Current of Air-Stable Organic Gas Sensor for Monitoring of Breath Ammonia in Hemodialysis Patients
(2019-04-01)
Yu, Shang-Yu
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Tung, Tin-Wei
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Yang, Hong-Yu
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Chen, Guan-Yu
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Shih, Che-Chi
Point-of-care (POC) application for monitoring of breath ammonia (BA) in hemodialysis (HD) patients has emerged as a promising noninvasive health monitoring approach. In this context, many organic gas sensors have been reported for BA detection. However, one of the major challenges for its integration with affordable household POC application is to achieve stable performance for accuracy and high operational current at low voltage for low-cost read-out circuitry. Herein, we exploited the stability of the Donor Acceptor polymer on the cylindrical nanopore structure to realize the sensors with a high sensitivity and stability. Then, we proposed a double active layer (DL) strategy that exploits an ultrathin layer of Poly(3-hexylthiophene-2,5-diyl) (P3HT) to serve as a work function buffer to enhance the operational current. The DL sensor exhibits a sustainable operational current of microampere level and a stable sensing response even with the presence of P3HT layer. This effect is carefully examined with different aspects, including vertical composition profile of DL configuration, lifetime testing on different sensing layer, morphological analysis, and the versatility of the DL strategy. Finally, we utilize the DL sensor to conduct a tracing of BA concentration in two HD patients before and after HD, and correlate it with the blood urea nitrogen (BUN) levels. A good correlation coefficient of 0.96 is achieved. Moreover, the feasibility of DL sensor integrated into a low-cost circuitry was also verified. The results demonstrate the potential of this DL strategy to be used to integrate organic sensor for affordable household POC devices.
Correlation between breath ammonia and blood urea nitrogen levels in chronic kidney disease and dialysis patients
(2020-07-01)
Chen, Chang-Chiang
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Hsieh, Ju-Chun
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Chao, Cheng-Han
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Yang, Wei-Shun
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Cheng, Hui-Teng
Previous studies have shown that breath ammonia (breath-NH3) concentration is associated with blood urea nitrogen (BUN) levels. However, interindividual variations in breath-NH3 concentrations were observed. Thus, the present study aimed to assess the effect of oral cavity conditions on breath-NH3 concentration and to validate whether the measurement of breath-NH3 concentration is feasible in clinical settings. A total of 125 individuals, including patients with stage 3 to 5 chronic kidney disease (CKD3-5), those on dialysis, and healthy participants, were recruited. A nanostructured sensor was used to detect breath-NH3 concentrations. Pre- and post-gargling as well as pre- and post-hemodialysis (HD) breath-NH3, salivary pH, and salivary urea levels were measured. Breath-NH3, salivary urea, salivary pH, and BUN levels were positively correlated to each other. Breath-NH3 concentrations were associated with BUN levels (r = 0.43, p < 0.001) and were significantly higher in CKD3-5 (p < 0.005) and dialysis patients (p < 0.001) than in healthy participants. Higher correlation coefficients were noted between breath-NH3 concentrations and BUN levels during follow-up (r = 0.59-0.94, p < 0.05). When the cutoff value of breath-NH3 was set at 523.65 ppb, its sensitivity and specificity in predicting CKD (BUN level >24 mg dl(-1)) were 87.6% and 80.9%, respectively. Breath-NH3 concentrations decreased after HD (p < 0.001) and immediately after gargling (p < 0.01). Breath-NH3 concentration, which was affected by gargling, was correlated to BUN level. The measurement of breath-NH3 concentration using the nanostructured device may be used as a tool for CKD detection and personalized point-of-care for CKD and dialysis patients. The current study had a small sample size. Thus, further studies with a larger cohort must be conducted to validate the effect of oral factors on breath-NH3 concentration and to validate the benefit of breath-NH3 measurement.
Modulated gas sensor based on vertical organic diode with blended channel for ppb-regime detection
(2016-07)
Chuang, Ming-Yen
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Chen, Jian-Nan
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Zan, Hsiao-Wen
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Lu, Chia-Jung
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Meng, Hsin-Fei
We demonstrate an extremely sensitive ammonia gas sensor based on vertical organic diode to exhibit a 1 ppb detection limit. Using phenyl-C61-butyric acid methyl ester (PCBM) as the sensing layer, the nano porous structure enlarges the surface to volume ratio and hence realizes the ppb-regime sensitivity. The proposed vertical nano-junction (VNJ) organic diode is then investigated by changing the semiconducting materials (i.e. sensing material). In addition to a pure n-type or p-type sensing material, the blend of n/p organic semiconductor (PCBM/P3HT) is used to react with gas. Changing the n/p blending ratio from 0 to 100% delivers a tunable gas response to ammonia and nitric oxide, hence demonstrating a sensing map concept with good selectivity. (C) 2016 Elsevier B.V. All rights reserved.
Near-Infrared Laser-Annealed IZO Flexible Device as a Sensitive H2S Sensor at Room Temperature
(2020-06-03)
Chang, Po-Yi
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Lin, Ching-Fu
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Rouphael, Samer El Khoury
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Huang, Ting-Hsuan
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Wu, Chang-Mao
A metal-oxide material (indium zinc oxide [IZO]) device with near-infrared (NIR) laser annealing was demonstrated on both glass and bendable plastic substrates (polycarbonate, polyethylene, and polyethylene terephthalate). After only 60 s, the sheet resistance of IZO films annealed with a laser was comparable to that of thermal-annealed devices at temperatures in the range of 200-300 degrees C (1 h). XPS, ATR, and AFM were used to investigate the changes in the sheet resistance and correlate them to the composition and morphology of the thin film. Finally, the NIR-laser-annealed IZO films were demonstrated to be capable of detecting changes in humidity and serving as a highly sensitive gas sensor of hydrogen sulfide (in ppb concentration), with room-temperature operation on a bendable substrate.
One-Minute Fish Freshness Evaluation by Testing the Volatile Amine Gas with an Ultrasensitive Porous-Electrode-Capped Organic Gas Sensor System
(2017-04-01)
Chang, Liang-Yu
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Chuang, Ming-Yen
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Lu, Chia-Jung
In this work, we successfully demonstrate a fast method to determine the fish freshness by using a sensing system containing an ultrasensitive amine gas sensor to detect the volatile amine gas from the raw fish meat. When traditional titration method takes 4 h and complicated steps to test the total volatile basic nitrogen (TVB-N) as a worldwide standard for fish freshness, our sensor takes 1 min to deliver an electrical sensing response that is highly correlated with the TVB-N value. When detecting a fresh fish with a TVB-N as 18 mg/100 g, the sensor delivers an effective ammonia concentration as 100 ppb. For TVB-N as 28-35 mg/100 g, a well-accepted freshness limit, the effective ammonia concentration is as 200-300 ppb. The ppb-regime sensitivity of the sensor and the humidity control in the sensing system are the keys to realizing fast and accurate detection. It is expected that the results in this report enable the development of on-site freshness detection and real-time monitoring in a fish factory.
OPASS: AN ONLINE PORTFOLIO ASSESSMENT AND DIAGNOSIS SCHEME TO SUPPORT WEB-BASED SCIENTIFIC INQUIRY EXPERIMENTS
(2011-04-01)
Su, Jun-Ming
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Lin, Huan-Yu
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Tseng, Shian-Shyong
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Lu, Chia-Jung
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資訊工程學系
Promoting the development of students' scientific inquiry capabilities is a major learning objective in science education. As a result, teachers require effective assessment approaches to evaluate students' scientific inquiry-related performance. Teachers must also be able to offer appropriate supplementary instructions, as needed, to students. Scientific inquiry capabilities should be assessed by evaluating students' scientific inquiry portfolios in actual hands-on experiments. Although virtual laboratory systems can reduce the cost of conducting scientific inquiry experiments, the manual portfolio assessment approach is still difficult and time-consuming for teachers. Therefore, in this paper, in order to provide students with personalized learning guidance concerning not only the conceptual knowledge, but also the high-order, integrative abilities of scientific inquiry, an Online Portfolio Assessment and Diagnosis Scheme, called OPASS, was proposed to assist teachers in automatically assessing and diagnosing students' abilities as they relate to scientific inquiry performance. Personalized diagnostic reports were generated by employing the rule-based inference approach, which diagnosed learning problems and provided corresponding reasons and remedial suggestions based on teacher-defined assessment knowledge of the scientific inquiry experiment. For the evaluation, experimental results showed that the OPASS was helpful and beneficial for both students and teachers.
Organic Gas Sensor with an Improved Lifetime for Detecting Breath Ammonia in Hemodialysis Patients
(2017-12-01)
Chuang, Ming-Yen
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Chen, Chang-Chiang
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Lu, Chia-Jung
In this work, a TFB (poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-s-butylphenyl)diphenylamine)]) sensor with a cylindrical nanopore structure exhibits a high sensitivity to ammonia in ppb-regime. The lifetime and sensitivity of the TFB sensor were studied and compared to those of P3HT (poly(3-hexylthiophene)), NPB (N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine), and TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl) benzenamine]) sensors with the same cylindrical nanopore structures. The TFB sensor outstands the others in sensitivity and lifetime and it shows a sensing response (current variation ratio) of 13% to 100 ppb ammonia after 64 days of storage in air. A repeated sensing periods testing and a long-term measurement have also been demonstrated for the test of robustness. The performance of the TFB sensor is stable in both tests, which reveals that the TFB sensor can be utilized in our targeting clinical trials. In the last part of this work, we study the change of ammonia concentration in the breath of hemodialysis (HD) patients before and after dialysis. An obvious drop of breath ammonia concentration can be observed after dialysis. The reduction of breath ammonia is also correlated with the reduction of blood urea nitrogen (BUN). A correlation coefficient of 0.82 is achieved. The result implies that TFB sensor may be. used as a real-time and low cost breath ammonia sensor for the daily tracking of hemodialysis patients.
Photo-assisted recovery in ammonia sensor based on organic vertical diode
(2019-04-01)
Lin, Yu-Ting
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Yu, Shang-Yu
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Zan, Hsiao-Wen
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Yeh, Ping-Hung
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Lu, Chia-Jung
In this article, a photo-assisted gas sensor was provided to solve the slow recovering issue of the organic gas sensor. The proposed organic gas sensor can detect ammonia in parts-per-billion regime in 30 s and can be multiple uses, but the long recovery time about 5 min places difficulty to realize rapidly multiple-time sensing. Therefore, we used the photo-absorption ability in the organic semiconductor layer to generate the photocurrent and hence to compensate the current drop due to the ammonia absorption. The recovery time was significantly reduced to be only 1 min. The specific wavelength was also found to match the absorption spectrum in different organic sensing materials. As a comparison, the quartz crystal microbalance (QCM) was used to clarify the gas absorption and desorption mechanism. It is believed that this photo-assisted gas detection could be a general method to solve the slow recovery in organic-based gas sensors.
Room-temperature-operated organic-based acetone gas sensor for breath analysis
(2018-05-01)
Chuang, Ming-Yen
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Lin, Yu-Ting
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Tung, Ting-Wei
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Chang, Liang-Yu
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Zan, Hsiao-Wen
The major merits of organic-based sensors include their low cost, room-temperature operation, and small size. However, their sensitivity and selectivity are concerning, especially in the application of breath analysis. In this work, organic-based sensors were developed based on cylindrical nano-pore structures, which enhanced the sensitivity down to ppb levels. The sensing performance was demonstrated both in pure nitrogen and ambient air. The sensor constructed with poly[(9,9-dioctylfluoreny1-2,7-diy1)-co-(4,41(N-(4-sec-butylphenyl)diphenylamine)] (TFB) exhibited a 5% sensing response to 300 ppb of acetone in ambient air. In addition, the sensor's response to other major breath components, including nitric oxide, ethanol, carbon dioxide, and ammonia, was also established. The results showed that the TFB sensor also exhibited a good response to ammonia. Therefore, a humidification tube was designed as an ammonia filter to improve selectivity. The concept of integrating a highly sensitive sensor with a customized sensing system shows promise for medical applications. (C) 2018 Elsevier B.V. All rights reserved.
UV-enhanced room-temperature ultrasensitive NO gas sensor with vertical channel nano-porous organic diodes
(2020-10-01)
Madhaiyan, Govindasamy
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Tung, Ting-Wei
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Lu, Chia-Jung
In this work, we successfully proposed an organic semiconductor gas sensor on vertical channel design to exhibit an ultra-sensitive response to nitric oxide gas (10 ppb) at room temperature. The effect of ultra-violet (UV) irradiation (lambda =365 nm) on sensing performance of solution processed vertical organic diode (VOD) has been investigated. After implementing a simple and low-cost UV treatment, the sensing response of PBDTTT-C-T based NO sensor is significantly enhanced from 93 % to 233 % at 1 ppm. In addition, we also introduced a new strategy to tune the selectivity of organic gas sensors by using photochromic molecule and organic semiconductor blends. With the 1 Wt% spiropyran dopant, the sensor response to ammonia can be considerably suppressed, hence the response ratio between NO and ammonia can be improved from 2.9 to 16.0, indicating an improved selectivity. The proposed ultrasensitive and selective NO gas sensor have great potential for exhaled breath detection (asthma patients) and environmental monitoring.