Study on Optical Efficiency of Organic Photovoltaic Devices with Multi-Tip Metal Nanostructures

As a new generation of photovoltaic devices, organic polymer solar cell (Organic Solar Cell, OSC) have attracted wide attention of researchers in recent years because of their unique advantages such as simple process, low energy consumption, low cost and large area preparation. However, the development of OSC has encountered bottlenecks: the low carrier mobility of photovoltaic materials forces the thickness of the active layer of OSC to be reduced as much as possible to meet the requirements of effective collection of photogenerated carriers, while the thinner absorption layer will lead to serious optical absorption loss and device performance degradation. Therefore, how to enhance the optical absorptivity of OSC on the premise of effective carrier collection has become a research hot-spot. Based on this characteristic, with the help of finite element method, the structure model of OSC with multi-tip metal nanoparticles is established, and the effects of metal nanospheres and star particles on OSC light absorption factors are studied systematically. Firstly, the effects of introducing metal nanoparticles into different functional layers of OSC (active layer and buffer layer) are compared and analyzed to determine the introduction location of metal nanoparticles in OSC. Secondly, the localized resonance enhancement rules of spherical and cubic metal nanoparticles in the functional layer are discussed. Combined with the theoretical model, the optimal design method of metal nanoparticles structure parameters (size and period) is established. The results show that the absorption enhancement of metal nanoparticles in the active layer of OSC is higher than that in the buffer layer. On the one hand, it can stimulate more electron hole pair separation, improve the separation rate of electron hole pair, on the other hand, it can also make the separated electron hole to obtain more energy, recombination becomes relatively difficult, and the arrival rate of the battery electrode is improved.