Research On Preparation And Properties Of Organic Solar Cells Based On Polymer Donor Materials

Organic solar cells are considered to be a new type of renewable energy utilization technology with great potential due to its low cost,light weight,flexibility,light transmission,simple manufacturing,and ease of mass production.It has a broad development space in the future.In the course of more than 60 years of development of organic solar cells,the development of a series of polymer donor materials(such as P3 HT,PTB7,PTB7-Th,PBDB-T,etc.)has constantly refreshed the highest efficiency of the device.At the same time,the optimization process of the device also plays a crucial role in improving the performance.The optimization strategies such as interface modification of transport layer,additives,and annealing can effectively improve the efficiency and stability of organic solar cells.This article is based on the classic PTB7-Th: PC71 BM system and improves the performance of battery devices by adopting two strategies: interface modification of transport layer and additives.The main work contents are as follows:1.Use the method of modifying the transport layer to optimize the electron transport layer in the device to improve device efficiency.Using PTB7-Th and PC71 BM as the main body to build an inverted structure of the binary battery,doped POT2 T into ZnO as an electron transport layer,to achieve the improvement of battery device efficiency,and further studied the role of POT2 T in the electron transport layer The role.When doped with 5 wt% of POT2 T,the efficiency of the device is the highest.The open circuit voltage(VOC)of the battery device is 0.783 V,the short circuit current density(JSC)is 18.01 mA / cm2,the fill factor(FF)is 69.87%,and the photoelectric conversion The efficiency(PCE)is 9.84%,which is 10% higher than that of the control device(PCE = 9.03%).Studies have shown that POT2 T doping into ZnO improves the exciton dissociation rate of the device and enhances the transmission efficiency of the device's exciton;meanwhile,POT2 T also optimizes the surface morphology of the ZnO film and increases the active layer material and electron transport The area of the contact interface of the layer is conducive to charge transfer.2.Using the method of adding additives to the active layer solution,the active layer in the device is optimized to improve the device performance.Polyethylene glycol(PEG)as an additive was added to the mixed solution mainly composed of PTB7-Th and PC71 BM to prepare an active layer,which realized an efficient and stable organic solar cell device,and further studied the effect of PEG on the battery device Mechanism.When adding 4 wt% PEG to the PTB7-Th: PC71 BM binary system,the efficiency of the device reached the highest,at this time VOC was 0.792 V,JSC was 20.20 mA / cm2,FF was 70.65%,PCE reached 11.30%,compared with the control Group devices(PCE = 9.44%)increased by 20%.Studies have shown that the addition of PEG can optimize the surface morphology of the active layer and the crystallization of the polymer,while optimizing the distribution of the active layer material in the vertical direction,thereby playing a role in optimizing device performance.The addition of PEG also improves the tolerance of the active layer of the device to changes in thickness and the stability of the device in high humidity environments,and improves the efficiency of devices prepared with green solvents and in an air environment.At the same time,PEG can also play a role in improving the efficiency of the device in the PBDB-T: PC71 BM system,indicating that PEG can be applied in a variety of systems.This paper studies two optimization strategies for polymer organic solar cells,and provides some ideas for further optimization of device performance.