▎ 摘　　要

The photo-induced degradations in the photovoltaic performance of high-efficiency P3CT-Na based CH3NH3PbI3 (MAPbI(3)) solar cells were investigated by using a boron-doped graphene quantum dots (BG-QDs):poly(methyl methacrylate) (PMMA) film coated glass substrate or a glass substrate as the light shielding window. With the use of a BG-QDs:PMMA film coated glass substrate, the power conversion efficiency (PCE) of the P3CT-Na based MAPbI(3) solar cell slightly decreased from 18.50% to 18.23% under one sun illumination for 20 min. To investigate the photo-induced changes in the MAPbI(3)/P3CT-Na/ITO/glass samples with and without the shielding from a BG-QDs:PMMA/glass substrate, the X-ray diffraction patterns, absorbance spectra and photoluminescence spectra are measured and analyzed. It shows that the blue and green photons can increase the defect density in the MAPbI(3) thin film and thereby resulting in the irreversible photovoltaic performance. Fortunately, the BG-QDs:PMMA thin film is not only used to shield the high energy photons, but also can be used as an efficient down-converter and thereby resulting in a stable and high-efficiency perovskite solar cell.