Research Of Organic-inorganic Hybrid Optoelectronic Device Using Amino Acid As Interfacial Layer

Organic/inorganic hybrid optoelectronic devices have been attracting growing interests. Hybrid devices combine the advantages of both the organic semiconductor material and the inorganic semiconductor material. At the same time, they potentially overcome their disadvantages. Interface modification is one of the most effective methods to improve device performance when the active layer material is fixed. In this thesis, we mainly study the effect of interface modification on organic/inorganic hybrid optoelectronic devices. We choose two kinds of small biological molecule-amino acid as interface modification material. Then we do research on the device performance and the function mechanism.The main research contents including:Ti O2 is made as the modification layer of hybrid device cathode. Arginine and asparagine are chosen as the interface modifier by SAM. In the research of solar cell performance, the device with the active layer of P3HT:PCBM and the interfacial layer of arginine has better performance. Compared with the unmodified device, the PCE、Voc、Jsc、FF and EQE increased from 1.45% to2.3%, 0.48 V to 0.58 V, 8.39 m A/cm2 to 9.24 m A/cm2,, 36.1% to 43% and 45.6%to 51.9%, respectively. In the research of photodetctor performance, the device with the active layer of PTB7-ICBA and the interfacial layer of arginine has better performance. Compared with unmodified device, the Jd decreases by 5times, the RR increases by exceeding 3 times and the D* increases by about 3times. The modification mechanism is that the work function of Ti O2 would decrease with amino acid modification for amino acid is zwitter-ion. In this situation, the Ti O2 can match with the LUMO levels of acceptor well and the interface contact would be more and more close to Ohmic contact.For the period of amino acid SAM is so long and uncontrolled that we introduce the method of electrotophoresis(EP) to achieve the interface bond of the amino acid and the cathode surface. This method takes little time and well controlled. For Ti O2 is wide bandgap semiconductor material, it is insulating without sufficient motivation. It is not suitable for EP. In this chapter, amino acid is directly bonded onto the ITO surface by EP. The modified device by asparticacid shows much greater performance.Compared with unmodified device, the PCE increases from 1.23% to 2.79%,the Jsc increases by exceeding 30%, the Voc increases by 0.1 V, the EQE increases by nearly 50%, respectively. The mechanism is similar to SAMs, the difference is that the electric field makes the function better.