Elucidation of electrical conductivity of DNA polyion-complexes and the applications for optoelectronic devices

DNA形成双螺旋结构，其包含四个碱基（腺嘌呤（A）、胞嘧啶（C）、鸟嘌呤（G）和胸腺嘧啶（T））。它基本上是大量的π电子。由于DNA中的四个碱基的规则序列可以被假设为导线，因此我们可以使用DNA作为电活性材料来创建具有高级功能的新型电子器件应用。结合单极空穴（TPD）和电子（POXD）传输层的DNA-CTMA单层和双层器件的J-V特性清楚地证明了DNA-CTMA的导电性。在10 V电压下，DNA-CTMA单层器件的电流密度J= 590 mA/cm ^2，结合TPD的DNA-CTMA双层器件的电流密度J= 11 mA/cm ^2，结合POXD的DNA-CTMA双层器件的电流密度J=0.02mA/cm ^2。这些结果清楚地表明DNA-CTMA层基本上具有双极载流子输运特性。我们进一步评估了四种基底的真空沉积薄膜的基本电导率。在10 V电压下，腺嘌呤、胞嘧啶、鸟嘌呤和胸腺嘧啶的电流密度分别为J= 180 mA/cm ~ 2、J=0.35mA/cm ~ 2、J= 10 mA/cm ~ 2和J=2.3mA/cm ~ 2。此外，我们确认了电荷载流子传输特性的四个基地，通过使用它们在电致磷光OLED。研究<ext>了四种碱基作为HTL的OLED的η-J特性。腺嘌呤、胞嘧啶和鸟嘌呤作为HTL的最大η_<ext>（max）为8.0±0.2%，表明这四种碱基的真空沉积膜可用作OLED中的HTL。我们的研究结果清楚地表明DNA双螺旋本质上具有半导体特性，DNA-CTMA和真空沉积基膜具有潜在的半导体应用前景。

DNA forms a double helix structure that contains four bases (adenine (A), cytosine (C), guanine (G), and thymine (T). It is basically an abundance of πelectrons. Because a regular sequence of the four bases in DNA can be assumed to be a conducting wire, we can create novel electronic device applications with advanced functions using DNA as an electrically active material.In this study, we evaluated fundamental conductivity of the DNA-CTMA thin film. The J-V characteristics of DNA-CTMA single and double layer devices combined with unipolar hole (TPD) and electron (POXD) transport layers clearly demonstrated electrical conductivity of DNA-CTMA. We observed that the current density of J=590mA/cm^2 with the DNA-CTMA single layer device, J=11mA/cm^2 with the DNA-CTMA double layer device combined with TPD and J=0.02mA/cm^2 with the DNA-CTMA double layer device combined with POXD at an applied voltage of 10V. These results clearly suggest that the DNA-CTMA layer basically has bipolar carrier transport characteristics.We further evaluated fundamental conductivity of the vacuum deposited thin films of the four bases. We observed that the current density of J=180mA/cm^2 with Adenine, J=0.35mA/cm^2 with Cytosine, J=10mA/cm^2 with Guanine and J=2.3mA/cm^2 with Thymine at an applied voltage of 10V. Further, we confirmed charge carrier transport characteristics of the four bases by using them in electrophosphorescence OLEDs. Theη_<ext>-J characteristics of OLEDs with four bases as HTL were investigated. Adenine, Cytosine and Guanine as HTL demonstrated maximumη_<ext>〜8.0±0.2% demonstrating that the vacuum deposited films of the four bases are useful as a HTL in OLED.Our results dearly demonstrated that DNA double helix intrinsically have semiconducting characteristics and the DNA-CTMA and the vacuum deposited base films have potential for semiconductor applications.