Research On The Preparation And Performance Of Efficient And Stable Perovskite Solar Cell And Perovskite/Silicon Tandem Solar Cell

Perovskite photovoltaic（PV）materials have made great progress in the PV field in recent decades because of their excellent photoelectric performance.The power conversion efficiency（PCE）of perovskite solar cells（PSCs）has reached 25.7%,which is close to the highest efficiency（26.7%）of single-junction crystalline silicon solar cells.In addition,the efficiency of the tandem solar cells（TSCs）based on perovskite top cells and silicon bottom cells has reached 31.25%,exceeding the theoretical limit of efficiency（29.4%）for single-junction crystalline silicon solar cells.The perovskite/silicon TSCs technology is one of the most promising PV technologies to achieve high efficiency while keeping the simple fabrication process and low cost.In commercial applications,the stability and reproducibility of high efficiency PV devices are the main challenges facing the perovskite solar cells and perovskite/silicon tandem solar cells technologies.The perovskite layer and its associated interfaces are the main locations of defects,which can lead to serious charge recombination and material degradation,seriously affecting the stability of the device.Secondly,the charge extraction and transport capabilities of perovskite and its related interfaces are also related to the energy level arrangement at the interface and the conductivity of the charge transport layer.At the same time,the adverse reaction at the interface is also one of the important factors affecting the stability of perovskite layer.In this context,this paper studies and optimizes the interface properties of perovskite layer and perovskite/charge transport layer by means of additive engineering and interface engineering,and further explores the reaction mechanism and action principle of additives in the crystallization growth process of perovskite film and organic molecules in the interface modification process.On this basis,the single-junction perovskite solar cells and perovskite/silicon tandem solar cells with high efficiency and stability were prepared.The main research contents are as follows:1.（2-hydroxyethyl）amine hydroiodide（EOAI）is used to regulate the interface properties of SnO₂/perovskite.The-NH₃⁺positive and I^-negative ion group in EOAI,which is anchored on the surface of SnO₂ through-OH groups,can effectively passivate the interface defects of perovskite film.Furthermore,the EOAI-modified ETL has a smaller work function（W_F）and E_CB,which facilitates efficient charge transport and collection.In addition,the EOAI also helps to improve the crystallinity of the perovskite layer.As a result,the PSCs with EOAI-modified SnO₂ ETL produce a champion PCE of 22.61%with high environmental stability.At the same time,the 1.68 e V wide-band gap PSC achieved a PCE of nearly 20%,and its associated semitransparent device also achieved an efficiency of over 17%.2.The EDTA-2M molecules（M stands for K,Rb or Cs）are introduced into SnO₂precursor solution to stabilize SnO₂ colloid aqueous solution and improve the electrical and surface properties of SnO₂ films.Under the help of EDTA-2M molecules,the electron mobility of SnO₂-based perovskite films is increased.In addition,the EDTA-2M molecules can effectively passivate the defects at the SnO₂/perovskite interface and improve the quality of the perovskite films.All the improvements suppress the carriers recombination and reduce the open circuit voltage(V_OC)loss.Finally,the device based on E-SnO₂-2Rb as ETL with a perovskite bandgap of 1.57e V reached a champion efficiency of 23.30%(V_OC is 1.171V)with a negligible hysteresis,and the unencapsulated PSCs based on E-SnO₂-2Rb only drop 5%of the initial efficiency after being exposed to the ambient atmosphere for 1200 h.Meanwhile,the E-SnO₂-2Rb-based four-terminal（4T）perovskite/silicon tandem device also achieved an efficiency of 26.60%.3.The F-type pseudo-halogen additive（PF₆^-）is employed into the perovskite precursor solution to improve the performance of perovskite films.The perovskite film with F-type pseudo-halogen additive has a larger grain size and higher crystal quality with lower defect density.At the same time,the perovskite lattice expansion due to the substitution of I^-/Br^-by the F-type pseudo-halogen anions,and the stress distortion in the perovskite film is released,which effectively suppresses the carrier recombination,reduces the charge transfer loss,and inhibits the phase separation.Finally,the inverted 1.67 e V PSC achieved an efficiency of more than 20%,with an impressive fill factor（FF）of 84.02%and excellent device stability.Meanwhile,the PCE of the 4T perovskite/silicon tandem solar cell based on the improved perovskite film also reached 27.35%.4.The 4-（Di-p-tolylamino）benzaldehyde（BZD）organic molecule with multifunctional groups is introduced into the Ni Ox/perovskite interface as interface modification layer,which can be achieved the double passivation of Ni Ox and perovskite layer.The introduction of BZD molecule effectively improved the interface contact between Ni Ox and perovskite layer and optimized the energy level arrangement at the interface,which enhances the interfacial interconnection between Ni Ox and perovskite layer.Meanwhile,the existence of BZD can also effectively suppress the adverse reaction between Ni Ox and perovskite layer.Finally,the champion efficiency of the BZD-modified MAPb I₃-based perovskite solar cell reaches 20.90%,which is much higher than the 18.40%efficiency of the control device.Meanwhile,after 30 days of storage in atmospheric environment（RH≤30%,RT）,the device can still maintain more than 80%of the initial efficiency.In addition,the PCE of the Ni Ox-based two-terminal（2T）perovskite/silicon tandem solar cell also reached 25.48%.