Study of Photoresponsive Properties of DNA Biopolymer Composites

• Main Authors: Wang, Jo-Hsin, 王若馨
• Other Authors: Hung, Yu-Chueh
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/8u62ae

碩士 === 國立清華大學 === 光電工程研究所 === 106 === Deoxyribonucleic acid (DNA), a natural, organic and harmless material, has been widely used in a lot of fields. DNA-based biopolymer films demonstrated in many kinds of optoelectronic devices, have several advantages, including ease of fabrication, flexible and high transmittance in the visible region. On the other hand, the complex behaviors of organic materials, including interatomic resonance, intermolecular resonance or charge transportation in organic materials play crucial roles on the electrical and optical properties of devices. For reasons outlined above, it is of great importance to understand the role of DNA biopolymer composites in optoelectronic devices. However, there is still lack of in-depth investigation on the generation of electron-hole pairs, charge transportation and charge recombination properties of devices base on DNA biopolymer composites. In this study, we employed a simple sandwich structure based on DNA biopolymer composites to investigate the photoreponsive properties. In the first part of this study, we analyzed the optoelectronic properties through change the excitation wavelength, applied biases and intensity of incident light. The results were evaluated by normalized photoinduced current and responsivity, which showed that higher photoresponses were achieved with a shorter wavelength of light. Meanwhile, we fitted the photocurrent of the device with respect to optical power when irradiated by UV and violet light. The performance was explained by two mechanisms, which are related to continuous distribution of trapping centers and monomolecular recombination. The interfacial dipole at the biopolymer-metal interface could also be observed when changing the electrode materials. Based on the measurement results, we discussed possible origins of photocurrent and further studied the performance by doping silver nanoparticles (Ag NPs) and varying the deposition rate of electrode. Lastly, we performed a reliability test of the device and discussed the results.