High performance phototransistors with organic/quantum dot composite materials channels

Abstract Nanomaterials, especially quantum dots, have become one of the most great potential channel transport layer materials in the field of photo detection mainly due to their particular light absorption characteristics. However, there are still many disadvantages such as low carrier transport capability possibly attributable to the discontinuity nature of materials. Therefore, particular phototransistors with pentacene/CdSe@ZnS QDs composite materials channels have been prepared by simply blending and spin-coating 6,13-Bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) and QDs solution in weight ratio of 3:1. The particular device architecture with organic/quantum dot composite materials channels effectively combined the high carrier mobility advantage of organic semiconductors with the strong absorption characteristic of quantum dots in specific optical band regions and further overcame the low conductivity shortcomings of pure quantum dot materials. The device with particular pentacene/CdSe@ZnS QDs composite channel exhibited excellent electrical and optical properties with current switch ratio Ion/off of 104, carriers mobility of ~0.161 cm2/V, photosensitivity P of 105, responsivity R of 0.33 mA/W and detectivity D of 1.48 × 1011 Jones at drain voltage of −35 V and light intensity of 1.6 mW/cm2, respectively, indicating that this composite, as one of the most promising channel transport layer material candidates for photodetector, provides one chance to improve the characteristic of photodetector transistors just by using hybrid channel technology.