A comprehensive study was carried out to explore the influence of organic cations on high-performance perovskite absorber (PA) based photovoltaics. Scanning electron microscope, X-ray diffractometer, X-ray absorption edge structure spectrum, Hall measurement, absorbance spectrum and photoluminescence measurements were used to investigate the structural, electrical, optical and excitonic characteristics of PAs fabricated under different thermal annealing temperatures from 60℃ to 140℃. The decrease in the open-circuit voltage with an increase in the thermal annealing temperature can be explained as due to the reduced work function of the PA. The short-circuit current density (JSC) of the PA based photovoltaics is related to the efficiencies of light absorption and carrier collection, which results in an optimized JSC when the thermal annealing temperature is 120℃. The atomistic interaction between the organic cations and Pb-I framework strongly influences the absorption strength of PAs, as confirmed by the libration of organic cations shown by Raman scattering spectroscopy. In addition, the experimental results indicate that the power conversion efficiency can be further improved when the absorption strength of the PA and the energy-level alignment of each photovoltaic layer are simultaneously fulfilled. 

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Thin film Perovskite solar cells have drawn huge attention recently. By using the codes based on Matlab® environment and the semiconductor module based on COMSOL Multiphysics® software, nanometer-scale perovskite solar cell models with proper surface recombination rates were set up for simulation. The comparisons with the published results were also made.

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we utilized the electrospray technique for deposition solidified crystal precursors through the solid diffusion process in formation of CH3NH3PbI3-xClx film for perovskite planar heterojunction (PHJ) solar cell. The conversion efficiency of hybrid device could reach 9.3% PCE with impressive 19.71 mA/cm2 in JSC, 0.87 V in VOC, fill factor = 0.55.

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The open-circuit voltage of CH3NH3PbI3 based photovoltaics was enhanced from 0.85 V to 0.9 V, which resulted in an improvement of the average power conversion efficiency from 10.64% to 11.74% achieved by tuning the work function of the poly(3,4- ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transporting layer(HTL).

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Non-halogenated solvent was used to fabricate efficient solution-processed small molecule organic photovoltaics (OPVs). Power conversion efficiency (PCE) of 5.6% was achieved using toluene compared to 4.8 % using chloroform (CF). These results are promising in order to replace the toxic halogenated solvents commonly used in OPVs with more eco-friendly solvents.

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