Fabrication And Performance Research Of Organic-inorganic Hybrid Perovskite （CH₃NH₃Pb X₃） Based Solar Cell

Solar energy is undeniably considered as the most promising renewable energy in the future.One of the hottest topics in materials science in the past few years has been hybrid organic–inorganic perovskites,which have risen to stardom due to their remarkable properties in optoelectronic applications such as superb absorption coefficient,long carriers diffusion length,direct energy band gap and bipolar transporting property.This thesis mainly exhibited a series of systemic research and discussions about organic-inorganic hybrid perovskite film’s preparation process,optoelectronic property,atmosphere specificity and innovative electrons transporting layer,meanwhile,organic-inorganic hybrid perovskite based solar cells with outstanding performance have been also achieved.The main research contents and results are shown below:1.Using an extremely simple but promising two-step sequential subliming vapor deposition method,this segment grew high-quality perovskite CH3NH3 Pb I3 film with a uniform and continuous surface coverage.The perovskite film’s morphology and growth orientation can be well controlled by the growth temperature.The temperature influences on the power conversion efficiency（PCE）and the current-voltage hysteresis of the Spiro/CH₃NH₃PbI₃/TiO₂ P-i-N planar film solar cells were also investigated.Furthermore,a novel solvent annealed PCBM film was introduced between the TiO₂ compact layer and perovskite active layer,which not only reduced the J-V hysteresis obviously but also enhanced devices performance.After optimization of the fabrication temperature and devices’ structure,it was found that the PCEs of the solar cells fabricated at 120℃ on glass and flexible PET substrates can reach 15.59 % and 7.62 %,respectively.This promising approach provided a way to construct low-cost and large-area perovskite cell devices.2.In this segment,we presented a fast solvent-assisted molecule inserting（S-AMI）strategy to grow high-quality perovskite film,the perovskite film grown by S-AMI approach showed large and well-oriented grains and long carrier lifetime due to the reduced grain boundary.Solar cells constructed with these perovskite films yielded an high efficiency over 18% along with a high average fill factor of 80%,which is benefit from the enhanced carriers mobility and charges extraction efficiency.Moreover,these unsealed solar cell devices exhibited good stability in ambient atmosphere.Finally,large active area devices also achieved unforgettable performance.3.During the growth of CH₃NH₃PbI₃-xClx（MAPbI3-xClx）perovskite films by two-step inter-diffusion method,the presence of a trace amount of oxygen is critical to their physical properties and photovoltaic performance.As the oxygen concentration increases,random grain size distribution are observed.Moreover,by XRD,Raman scattering,and photoluminescence measurements,we observed that MAPbI3-xClx grains became more distorted and the electron-hole recombination rate were dramatically increase.Higher oxygen concentration triggered a sharp decrease in the current density and the fill factor of corresponding solar cells.This section proved the importance of controlling the oxygen atmosphere in the fabrication of high-performance perovskite solar cells.4.This part demonstrated an effective SnO₂ nanotubes array prepared by in–situ template self–etching（iTSE）strategy as electrons transport structure,and the growth mechanism of such SnO₂ nanotubes has been proposed based on a series of controllable experiments.Electrons extraction rate,incident light pathway,interface stability and devices’ UV stability were significant enhanced by utilizing this electrons transport structure.This work highlighted the importance of the ETL material selection and provided insights into achieving an ideal ETL/substrate homojunction to fabricate better devices.