Fabrication And Photoelectric Properties Of P-Cu₂O/n-ZnO Heterojunction Solar Cell

At present, the clean energy with non-polluting and renewable was developing urgently due to the environmental pollution and ecological destruction resulted from a large amount of fossil energy consumption around the world. Owing to the solar power with universality, huge reserves and pollution-free, it attracts a great attentions. Silicon solar cells with high performance and mature production technology are undoubtedly preferred. However, the high price and complicated technology in production of the silicon solar cell prevent the developing of the solar cell and application. It is a reasonable to probe and study the new material in solar cell to overcome the present challenges. In this parper, the p-Cu2O/n-ZnO heterojunction solar cell was fabricated, and the influence of deposition conditions of cuprous oxide was systematically investigated. The contents of the parper are arranged as follows.Firstly, a large amount of high density ZnO nanostructure was prepared by thermal evaporation on Al-doped ZnO (AZO)transparent conductive film with Au as catalyst in horizontal tube furnace. The morphologies and luminescence properties of ZnO nanostructures were investigated carefully by controlling the annealed temperature of the substrate (the AZO transparent conductive film deposited with Au). The rusults show that high density of ZnO nanorods were grown on the as-deposited and annealed substrate at300℃, while nanoparticles were observed on the substrates annealed at500℃and700℃The average diameters of the nanorods with single-crystalline structure were about50nm and80nm, and a Au nanoparticle was observed on the tips, so the grown mechanism of nanorods is VLS mechanism. Room temperature photoluminescence (PL) spectra show that all samples have a UV emission peak and a broad deep-level emission peak. Moreover, as the annealing temperature increases, the intensity of UV emission enhances and the intensity of deep-level emission declines.Secondly, the p-Cu2O/n-ZnO heterojunction film solar cell was constructed by depositing Cu2O film with electrochemical deposition (ECD) and prepared ZnO film with magnetron sputtering respectively. The influnce of the voltage on the the structure, morphology and optical property of Cu2O film and the performance of the p-Cu2O/n-ZnO heterojunction solar cell was studied carefully. The rusults show that the intensity of Cu2O (111) gradually increase with the increasing of deposition voltage; however, if deposition voltage was increasing, the Cu2O film preferred to growing along (200) direction. The p-Cu2O/n-ZnO heterojunction solar cell presents good diode characteristic and the solar cell has the best performance when the deposition voltage kept at1.00V.Finally, the p-Cu2O/n-ZnO heterojunction solar cells were fabricated by ECD with ZnO/AZO film as the working electrode and graphite as the auxiliary electrode and the Cu(CH3CO)2, C3H6O3as the electrolyte solution. In order to improve the performance of the p-Cu2O/n-ZnO heterojunction solar cell, the relationship between deposition time and the performance of the p-Cu2O/n-ZnO solar cell was investigated. The results show the intensity of Cu2O (111) diffraction direction and is stronggest and the photoelectric conversion efficiency is higher than others when deposition time is120minutes.