The Research Of Efficient Organic Perovskite Solar Cell

Perovskite solar cells(PSCs)are a new branch of solar cells,which are competitive products for clean energy generation and thus become a very hot research topic in recent years.The light trapping layer in PSCs,e.g.CH3NH3PbI3,has a perovskite-type cubic structure,for which reason these cells are called PSCs.This kind of organic-inorganic hybrid compound not only has a narrow forbidden band and high photoelectric conversion efficiency(PCE),but also has high carrier mobility and low preparation cost.Nowadays,the efficiency of photoelectric conversion of PSCs is increasing rapidly,which forms a research upsurge.Generally,a typical PSC consists of 6 layers of thin films:conductive layer(FTO),dense TiO2 layer,porous TiO2 layer,perovskite layer,hole transport layer,and electrodes.Although the specific function of each part in the cell may differ,their fundamental role is to make more separated photo-generated electrons and holes,to reduce the recombination of electrons and holes,and thus to improve the PCE of the battery.In the PSCs,film of each layer has great influence on the battery efficiency.In this thesis,I have mainly utilized the pulsed laser deposition(PLD),sol-gel method,and thermal evaporation to prepare perovskite solar cells and the main results are as follows:(1)Through extensive literature studies,multiple experiments,and measurements,the pure phase organic perovskite precursor liquid was prepared and its properties was investigated.The preliminary research on the application of perovskite in the electronics was conducted as well.(2)The dense TiO2 layer was prepared by PLD under different conditions,then the other parts of the battery were assembled in the same procedure and the photoelectric conversion efficiency of these cells was tested for comparison.Our result showed that the pulse number of 2000 gave the best efficiency,indicating the existing of optimal layer thickness.Furthermore,the efficiency increases with the oxygen pressure from 1 Pa to 10 Pa,implying in a certain range the less oxygen defects in TiO2 layer,the higher the efficiency.(3)According to a series of trials,the stability of PCSs is not high,which is a serious disadvantage issue.This problem will cause a lot of restrictions in future applications if not solved.PSCs are sensitive to both temperature and humidity,especially the later one.After extensive literature studies,carbon paste was selected as counter electrode of solar battery and the relevant tests was performed.This carbon battery electrode can not only reduce the expensive cost of noble metal electrodes,but also has certain effect on the isolation of water outside,hence improving the stability of the battery.