Electronic, Optoelectronic, and Thermoelectric Single-Molecule Devices with Different Molecular Unit-Length

Molecular devices have given impetus to the development of new electronic components. The transport process of organic molecules has a significant impact on device performance. Diketopyrrolopyrrole (DPPn, n = 1,2,3,4.) and derivative molecules have been widely explored due to their long-range and efficient transport properties. In this paper, the electronic, optoelectronic, and thermoelectric properties of single diketopyrrolopyrrole molecular devices with different molecular units are investigated. By adjusting the bias voltage, the single molecular devices show a negative differential resistance effect, for which the reasons are given. Molecular orbital energy levels are regulated by gate voltages to enable conversion of conductivity. The transformation of molecular device functions in time-varying alternating current transport is discussed in detail. Bias voltage regulation is performed for the molecular device optical response to produce better photocurrent, and finally the thermoelectric current of the device is also analyzed. This results reveal that single molecular electronic, optoelectronic, and thermoelectric properties are highly correlated with molecular unit-length, which provides guidance for the development of molecular devices with different unit lengths.

Automated summary

This paper investigates the electronic, optoelectronic, and thermoelectric properties of single diketopyrrolopyrrole molecular devices with different molecular units. The single molecular devices show a negative differential resistance effect under adjusted bias voltage, and the reasons for this effect are provided. The molecular orbital energy levels can be regulated by gate voltages for conductivity conversion. The transformation of molecular device functions in time-varying alternating current transport is discussed, and bias voltage regulation is performed for better photocurrent and analysis of thermoelectric current. These findings indicate a strong correlation between the electronic, optoelectronic, and thermoelectric properties of single molecular devices and the molecular unit-length, providing guidance for the development of molecular devices with different unit lengths.