Sturchture Design And Perfomance Simulation Of Photonic Crystals Modifing The Back Electrode Of Trancesparent Organic Photovoltaic Devices

The transparent organic photovoltaic devices have drawn considerable attention as the key application of organic solar cells, such as building windows, car windshields, greenhouse, mobile electronic devices as well as decorative arts products. Since the sun light irradiated to solar cell is certain, the more photons are absorbed by the active layer, the less photons pass through the device, and vice versa. Then, how to ensure sufficient photoelectric conversion efficiency and sunlight transmittance at the same time that resolving the contradiction of power generation and transparent has become the core research in structure of design of transparent organic solar cell. The widely accepted idea to resolve the contradictions is tuning the absorption and transmission bands of the device to make the solar cell absorb more near-infrared and ultraviolet sun light to ensure sufficient photoelectric conversion efficiency and less visible sunlight to guarantee enough transmittance.Based on the basic idea of transmitting visible light absorption of infrared light,we designed two photonic crystal with simple production process and good overall performance to modify the back electrode of the transparent organic solar cells, and both devices can selectively absorb the sun light. Details are as follows:1. Designed two cycles photonic crystal consisting of Si and Si O2 to modify the back electrode of the transparent organic solar cell with structure of ITO/Mo O3/PDTP-DFBT:PCBM/Ti O2/ITO. The absorption enhanced greatly in the 450 ~ 500 nm and 700 ~ 900 nm region, While ensuring transmission within 450 ~ 700 nm range. The short-circuit current density of the device reaches 17.25 m A/cm2, improved 36.5% compared to 12.63 m A/cm2 of non-photonic crystal device.2. Designed multi-cycle series photonic crystals consists of different thickness of Ti O2 and Li F to modify the back electrode of the transparent organic solar cell with structure of ITO/PEDOT:PSS/PDTP-DFBT:PCBM/Ag. The transmittance for visible light and absorption for near-infrared light enhanced selectivity at the same time, and the average transmittance reached 40.3%. What’s more the device can provide high-quality transmission spectrum For plant growth, and it’s short circuit current is also improved. By calculating the electric field distribution, we find it is the excitation of optical tamm state in the 400~700 region that makes the selectively enhancement effect of tandem photonic crystal.