Most thin-film photovoltaic modules are constructed on soda-lime glass(SLG)substrates containing alkali oxides,such as Na_(2)O.Na may diffuse from SLG into a module's active layers through P1 lines,an area between...Most thin-film photovoltaic modules are constructed on soda-lime glass(SLG)substrates containing alkali oxides,such as Na_(2)O.Na may diffuse from SLG into a module's active layers through P1 lines,an area between a module's constituent cells where the substrate-side charge transport layer(CTL)is in direct contact with SLG.Na diffusion from SLG is known to cause several important effects inⅡ-Ⅵand chalcogenide solar modules,but it has not been studied in perovskite solar modules(PSMs).In this work,we use complementary microscopy and spectroscopy techniques to show that Na diffusion occurs in the fabrication process of PSMs.Na diffuses vertically inside P1 lines and then laterally from P1 lines into the active area for up to 360 pm.We propose that this process is driven by the high temperatures the devices are exposed to during CTL and perovskite annealing.The diffused Na preferentially binds with Br,forming Br-poor,l-rich perovskite and a species rich in Na and Br(Na-Br)close to P1 lines.Na-Br passivates defect sites,reducing non-radiative recombination in the perovskite and boosting its luminescence by up to 5×.Na-Br is observed to be stable after 12 weeks of device storage,suggesting long-lasting effects of Na diffusion.Our results not only point to a potential avenue to increase PSM performance but also highlight the possibility of unabated Na diffusion throughout a module's lifetime,especially if accelerated by the electric field and elevated temperatures achievable during device operation.展开更多
基金the Jardine Foundation and Cambridge Trust for a doctoral scholarshipthe European Union(EU)Horizon 2020 research and innovation program under grant No.764047(ESPResSo)+12 种基金funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No.823717-ESTEEM3.J.F.Oacknowledges funding from the Engineering and Physical Sciences Research Council(EPSRC)Nano Doctoral Training Centre(EP/L015978/1)J.F.O.,G.K.,and R.A.O.acknowledge Attolight and EPSRC(EP/R025193/1)for funding and supporting the SEM-CL systemE.M.T.thanks the EU Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no.841265.S.D.S.E.M.T.acknowledge funding from the EPSRC(EP/R023980/1)the EPSRC Centre for Advanced Materials for Integrated Energy Systems(CAM-IES,EP/P007767/1)Cambridge Royce facilities grant(EP/P024947/1)S.D.S.acknowledges funding from the Royal Society and Tata Group(UF150033)from the European Research Council under the EU Horizon 2020 research and innovation program under grant No.756962(HYPERION)W.L.and J.L.M.-D.acknowledge support from the EPSRC(EP/L011700/1,EP/N004272/1)the Leverhulme Trust(RPG-2015-017)the Royal Academy of Engineering Chair in Emerging Technologies(CiET1819_24)We wish to acknowledge the support of the Henry Royce Institute(HRI)for F.U.K.through the Royce PhD Equipment Access Scheme enabling access to the NanoSIMS facility at Manchester.The NanoSIMS was funded by UK Research Partnership Investment Funding(UKRPIF)Manchester RPIF Round 2.This work was supported by the HRI,funded through EPSRC grants EP/R00661X/1,EP/S019367/1,EP/P025021/1,and EP/P025498/1
文摘Most thin-film photovoltaic modules are constructed on soda-lime glass(SLG)substrates containing alkali oxides,such as Na_(2)O.Na may diffuse from SLG into a module's active layers through P1 lines,an area between a module's constituent cells where the substrate-side charge transport layer(CTL)is in direct contact with SLG.Na diffusion from SLG is known to cause several important effects inⅡ-Ⅵand chalcogenide solar modules,but it has not been studied in perovskite solar modules(PSMs).In this work,we use complementary microscopy and spectroscopy techniques to show that Na diffusion occurs in the fabrication process of PSMs.Na diffuses vertically inside P1 lines and then laterally from P1 lines into the active area for up to 360 pm.We propose that this process is driven by the high temperatures the devices are exposed to during CTL and perovskite annealing.The diffused Na preferentially binds with Br,forming Br-poor,l-rich perovskite and a species rich in Na and Br(Na-Br)close to P1 lines.Na-Br passivates defect sites,reducing non-radiative recombination in the perovskite and boosting its luminescence by up to 5×.Na-Br is observed to be stable after 12 weeks of device storage,suggesting long-lasting effects of Na diffusion.Our results not only point to a potential avenue to increase PSM performance but also highlight the possibility of unabated Na diffusion throughout a module's lifetime,especially if accelerated by the electric field and elevated temperatures achievable during device operation.
