| Due to the high absorption coefficient,wide wavelength absorption range,longer carrier diffusion length and long lifetime of perovskite materials,the perovskite solar cell emerges.In 2009,perovskite materials were first applied to the photovoltaic devices with an efficiency of only 3.8%.In just a few years,the highest efficiency reported by perovskite solar cell has exceeded 22%.This amazing rate of efficiency improvement indicates that perovskite solar cells will become the mainstream of solar cell development.Due to the characteristics of low temperature preparation and simple process,a great many of researchers have put into the research of the inverted planar heterostructure perovskite solar cell.However,the PEDOT:PSS(poly(3,4-ethylene-dioxythiophene)-polystyrene sulfonic acid)has a lower HOMO level,and it is acidic and corrosive,which leads to lower performance of the device.To this end,researchers tried a lot of hole-transporting materials,such as molybdenum oxide,nickel oxide,copper oxide,etc.,to find a material with appropriate work function,excellent transmission performance and low cost.Among them,copper oxide has a high hole mobility and low cost,and it is one of the ideal transmission materials.In addition,one-dimensional nanowires have a large specific surface area and can form surface or interface effects,macroscopic quantum tunneling effects,and size effects.Therefore,the paper through the electrospinning Cu O nanowires(Nanowires-NWs)and PEDOT: PSS were as the composite hole transport layer,the author had successfully prepared perovskite solar cells with high performance,and the reason why Cu O NWs can improve the performance of device had been further studied.The detailed study is as follows:1.The Cu O NWs were successfully prepared by electrospinning.By changing the concentration of the precursor solution,the applied voltage,the receiving distance and the injection speed,the Cu O NWs with regular morphology and controllable diameter were obtained.0.4 g copper nitrate and 0.69 g PVP were dissolved in 10 m L of ethanol and 2 m L of glacial acetic acid to prepare the precursor solution.When the applied voltage is 10 k V,the receiving distance is 12 cm,and the injection rate is 0.1 mm/min,the Cu O NWs with regular morphology and an average diameter of 190 nm were prepared.Afterwards,the morphology,diameter distribution and crystal structure of nanowires were analyzed by optical microscopy and X-ray diffraction.2.Inverted planar perovskite solar cell devices with Cu O NWs and PEDOT:PSS as composite hole transport layers were designed.The influence of different receiving times(ie different coverage ratios)of NWs in the electrospinning process on the device performance was further studied.Through comparison,it is found that when the coverage rate of Cu O NWs is 4.2%,the performance of the device is most improved.The open circuit voltage(Voc)of the device is 0.98 V,the short circuit current density(Jsc)is 21.72 m A/cm2,the fill factor(FF)is 0.77,and the photoelectric conversion efficiency(PCE)is 16.35%,an increase of 21% over the reference device efficiency(13.5%).Through testing and analysis,it was found that Cu O NWs have a great benefit to charge transfer and hole extraction of the device.Subsequently,the same conditions of Zn O NWs was introduced into the device instead of Cu O NWs,and the efficiency of the device was increased by 13%.A geometric model was constructed and found that the improvement in the performance of Zn O NWs devices was due to the increase in interface area of NWs.Compared with PEDOT:PSS,Cu O has higher hole transmission capacity,and it is conductive to form hole transmission channel.Therefore,the efficiency of Cu O NWs device has increased by 8%.The research of this paper provides reference for NWs improving the performance of perovskite solar cells. |
PDF Full Text Request