Preparation Of High-performance All-inorganic Perovskite Solar Cell And Its Integration With Organic Solar Cell

The power conversion efficiencies(PCEs)of organic-inorganic hybrid perovskite and organic solar cells(OSCs)were improved significantly,which are approaching application threshold.However,they were limited by their poor thermal and light stability due to their photoactive layer containing organic components.All-inorganic perovskite solar cells(peroSCs)without containing organic component,making their excellent light and thermal stability,but their efficiency is limited by their wide band gaps.In order to address above stability issues,we present the proposal intending to combine an inorganic perovskite film with a bulk-heterojunction low-bandgap organic semiconductor film to construct a highperformance integrated device.By which,the light absorption complementary between wide-bandgap inorganic perovskite and low-bandgap organic semiconductor films was realized,which could enhance sun light utilization and improve device efficiency.In addition,the organic semiconductors can be used to passivate the defects of inorganic perovskite film and filter the incidental ultraviolet light.As a result,the moisture,light and thermal stabilities could be improved.Finally,this integrated concept and technology would simultaneously improve all-inorganic perovskite/organic integrated device efficiency and stability,which undoubtedly promote the development of thin-film solar cells toward application.The main results are as follows.(1)The synergistic effect of gradient thermal annealing and antisolvent realizes highperformance all-inorganic pero-SCsIn order to improve the efficiency of all-inorganic pero-SCs and reveal the relationship between the quality of all-inorganic perovskite crystal thin films and the device performance of solar cells,we use the synergistic effect of gradient thermal annealing(GTA)and antisolvent treatment(ATS).The strategy is beneficial for precisely controlling the growth rate of the CsPbI2Br crystals and the volatility of the solvent in the film formation process,thus optimizing the phase,morphology and defect states of CsPbI2Br.As a result,a high-quality CsPbI2Br film is obtained,and the resultant CsPbI2Br pero-SCs exhibits a high PCE of 16.07%.Moreover,the CsPbI2Br pero-SCs demonstrates excellent robustness against moisture,and also showed significantly improved UV-light stability.(2)Preparation of all-inorganic perovskite/organic four-terminal tandem solar cells with high UV light stabilityWe constructed an inorganic-perovskite/organic 4-terminal tandem solar cell(4T TSC)based on a semitransparent inorganic CsPbBr3 pero-SC as top cell and an OSC as bottom cell.The high-quality CsPbBr3 photoactive layer of the planar pero-SC was prepared with a dual-source vacuum co-evaporation method,and the resultant opaque planar pero-SC exhibited an ultrahigh open-circuit voltage(Voc)of 1.44 V and a high PCE of 7.78%.Importantly,the related semitransparent pero-SC could almost completely filter UV light and well maintain photovoltaic performance,and showed an extremely high average visible transmittance.When it was used to construct a 4T TSC,the top pero-SC acting as a UV-filter could utilize UV light for photoelectric conversion,avoiding the instability problem of UV light on the bottom OSC,and leading to a PCE of 14.03%for the all-inorganic perovskite/organic TSC.(3)Spatial distribution recast for high-performance all-inorganic perovskite/organic integrated solar cellsWe proposed a recast strategy to optimize the spatial distribution components of lowbandgap organic bulk-heterojunction(BHJ)film,and combined with an all-inorganic perovskite to construct a perovskite/BHJ integrated solar cell(ISC).With this strategy,the acceptors on the upper layer of the BHJ film can be effectively removed to form a donorrich upper surface and improve the ohmic contact with the anode.Moreover,the morphology of the BHJ film is optimized,which effectively inhibits the accumulation of acceptors and charge carrier recombination.As a result,the ISC is not only significantly extended and enhanced the photoresponse achieving a 20%increase in current density,but also exhibits a high Voc and fill factor(FF)at the same time.A record PCE of 11.08%based on CsPbIBr2 pero-SCs was realized;it simultaneously showed excellent long-term stability against heat and UV light.(4)Surface lattice reconstruction strategy toward enhanced photovoltage for monolithic all-inorganic perovskite/organic tandem solar cellsWe post treat the CsPbI1.8Br1.2 perovskite with trimethylammonium chloride(TACI),which induces a surface lattice reconstruction(SLR)process.The Cl-doping and TA+terminating could repair the surface pinholes,enhance the crystalline and passivate the defects.The SLR strategy can also optimize the surface potential and energy level,thus contributing to the film uniformity for a suppressed nonradiative recombination and an effective hole transport.As a result,the all-inorganic perovskite/organic two-terminal tandem solar cell(2T TSC)delivers a record PCE of 21.04%with an ultrahigh Voc of 2.053 V,which is approximately equal to the superposition of the respective Voc values of the subcells;The 2T TSC also simultaneously showed outstanding operational stability and UV stability.