Organic Solar Cells Incorporated With Coated Gold Nanorods

With the gradual depletion of conventional fossil fuels, we need to develop and exploit new energy resources urgently. Among diverse new energy resources, solar energy has attracted great attention. Organic solar cells has many advantages, such as wide variety of materials, low cost, simple preparation process, being compatible with the roll-to-roll process, and so on. At present, the energy conversion efficiency of organic solar cells is still too low, hindering their industrialization process. How to improve the energy conversion efficiency of organic solar cells has become a hot research topic. Metal nanoparticles which can excite localized surface plasmonic resonances have been introduced into organic solar cells aiming for improving the light absorption in the active layer while the thickness of the active layer is maintained.In this thesis, in organic solar cells based on a new active material of PTB7: PC70 BM, we doped different types of coated gold nanorods at different positions and researched on the influences of different doping processes on the cell performances. We researched when PEG-coated gold nanorods are incorporated into the active layer of conventional organic solar cell, how the device performance changes. We also investigated the changes of device performances when introducing SiO2-coated gold nanorods at the buffer/active interface of the inverted organic solar cells. The details include:1. By modifying the surface by PEG, the gold nanorods which are originally only water-soluble can be soluble in organic solvent. Then, we doped the PEG-coated gold nanorods into the active layer PTB7:PC70BM of conventional organic solar cell, and optimized the concentration of gold nanorods in the active layer. Results show that the short-circuit current of the devices increases after the incorporation of the particles, yielding the power conversion efficiency of the optimal device increases by 10.5% compared with that of the control device.2. We incorporated SiO2 coated gold nanorods between the ZnO layer and the active layer PTB7:PC70BM in an inverted organic solar cell and achieved the enhancement of light absorption in the active layer. Moreover, the silica coating can reduce exciton quenching at the surface of gold nanorods. We found that the introduction of SiO2-coated gold nanorods increases the short-circuit current density while not degrading other electrical characteristics of devices. As a result, the power conversion efficiency of the optimal device increases by 7.7% with respect to the control.At last, the work in this thesis is summarized and the possible future research topic is put forward.