Organic UV‐Sensitive Phototransistors Based on Distriphenylamineethynylpyrene Derivatives with Ultra‐High Detectivity Approaching 10<sup>18</sup>
Jingwei Tao, Dan Liu, Zhengsheng Qin, Bo Shao, Jiangbo Jing, Hongxiang Li, Huanli Dong, Bin Xu, Wenjing Tian
Abstract
Abstract Organic photodetectors with UV‐sensitivity are of great potential for various optoelectronic applications. Integration of high charge carrier mobility, long exciton diffusion length as well as unique UV‐sensitivity for active materials is crucial for construction of UV‐sensitive devices with high performance, however, very few organic semiconductors can integrate these properties simultaneously. Herein, two novel organic semiconductors containing large steric hindrance triphenylamine groups, 1,6‐distriphenylamineethynylpyrene (1,6‐DTEP) and 2,7‐distriphenylamineethynylpyrene (2,7‐DTEP) are designed and synthesized. It demonstrates that the single crystals of both 1,6‐DTEP and 2,7‐DTEP exhibit superior integrated optoelectronic properties of high charge carrier mobility, unique UV absorption, high photoluminescence quantum yields as well as small exciton binding energies. Organic phototransistors constructed using 1,6‐DTEP and 2,7‐DTEP single crystals show ultrasensitive performance with ultra‐high photoresponsivity of 2.86 × 10 6 and 1.04 × 10 5 A W −1 , detectivity ( D *) of above 1.49 × 10 18 and 5.28 × 10 16 Jones under 370 nm light illumination, respectively. It indicates the great potential of 1,6‐DTEP and 2,7‐DTEP‐based phototransistors for organic UV‐photodetector applications and also provides a new design strategy to develop series of better performance UV photoelectric organic materials for related research in organic optoelectronics.