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

DNA形成双螺旋结构，包含四种碱基(腺嘌呤(a)、胞嘧啶(C)、鸟嘌呤（G)和胸腺嘧啶(T)）。它基本上是π电子的丰度。因为DNA中四个碱基的规则序列可以被认为是一根导线，我们可以利用DNA作为电活性材料创造出具有先进功能的新型电子设备应用。在这项研究中，我们评估了DNA-CTMA薄膜的基本电导率。结合单极空穴（TPD）和电子（POXD）输运层的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。我们观察到，在10V电压下，DNA-CTMA单层器件的电流密度J=590mA/cm^2， DNA-CTMA双层器件与TPD结合时的电流密度J=11mA/cm^2， DNA-CTMA双层器件与POXD结合时的电流密度J=0.02mA/cm^2。这些结果清楚地表明，DNA-CTMA层基本具有双极性载流子传输特性。我们进一步评估了四种碱基真空沉积薄膜的基本电导率。在10V电压下，腺嘌呤的电流密度为180mA/cm^2，胞嘧啶的电流密度为0.35mA/cm^2，鸟嘌呤的电流密度为10mA/cm^2，胸腺嘧啶的电流密度为2.3mA/cm^2。此外，我们还利用这四种碱基在电磷光oled中证实了它们的载流子输运特性。研究了以HTL为基料的四种有机发光二极管的η <ext>-J特性。腺嘌呤、胞嘧啶和鸟嘌呤作为HTL的最大η为_<ext bb0 ~ 8.0±0.2%，表明这四种碱基的真空沉积膜在OLED中作为HTL是有用的。结果表明，DNA双螺旋结构具有半导体特性，DNA- ctma及其真空沉积基底膜具有半导体应用潜力。

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.