Study On Electron Transport Layer In Antimony Selenide Solar Cell

At present,the energy needed to support human development is mainly fossil energy.However,fossil energy is nearly exhausted,non-renewable and pollution problems are still not improved,so people are in urgent need of clean energy research and utilization.Solar cell has attracted much attention from researchers because of their reproducibility.At present,the market is basically dominated by silicon solar cells.However,thin film solar cells are rich in materials,simple in technology,and easy to be mass-produced.Compared with monocrystalline silicon solar cells,they have obvious advantages in reducing costs and gradually improving their efficiency.At present,Cd Te,Ga As and CIGS thin film solar cells have been commercialized and their efficiency is close to the photoelectric conversion rate of single crystal silicon cells.However,the large toxicity of Cd,the rarity of Te and the high price of In and Ga have been puzzling researchers.Therefore,it has become a research hotspot in recent years to seek low toxicity,abundant earth reserves,cheap price and excellent performance of electrical conversion materials.Recently,antimony selenide（Sb₂Se₃）has attracted much attention due to its low price,abundant reserves and low toxicity.In this paper,ITO/NPB/Sb₂Se₃/Alq3/Al thin film solar cells were prepared by thermal vacuum evaporation.We applied Alq3 as electron transport layer to antimony selenide thin film solar cell for the first time.Through the improvement of preparation and annealing process,the final result showed that the efficiency of the device increased from 2.2% to 3.8%after adding Alq3 layer.Through characterizing the characteristics of I-V,C-V and transient optical voltage,it is found that after adding Alq3 layer,the composition of photogenic carriers is inhibited and the interfacial state density is reduced,thus improving the performance of the device.In addition,we also prepared a bulk heterojunction solar cell device,device structure is:ITO/NPB/Sb₂Se₃/Sb₂Se₃:C60/C60/Alq3/Al.By improving the mixing ratio of Sb₂Se₃ and C₆₀,the thickness of Sb₂Se₃ layer and the thickness of C₆₀ layer,the device performance is continuously improved,and the photoelectric conversion rate of 3.61% is finally obtained,which provides a new idea for the structure of thin-film solar cell.Finally,we tried to replace Alq3 with PbI2 as the electron transport layer.By improving the thickness of PbI2 film,we finally found that the time electricity conversion rate was the highest at the thickness of 6 nm,reaching 3.23%.