摘要
Recent advances in heterojunction and interfacial engineering of perovskite solar cells(PSCs)have enabled great progress in developing highly efficient and stable devices.Nevertheless,the effect of halide choice on the formation mechanism,crystallography,and photoelectric properties of the lowdimensional phase still requires further detailed study.In this work,we present key insights into the significance of halide choice when designing passivation strategies comprising large organic spacer salts,clarifying the effect of anions on the formation of quasi-2D/3D heterojunctions.To demonstrate the importance of halide influences,we employ novel neo-pentylammonium halide salts with different halide anions(neoPAX,X=I,Br,or Cl).We find that regardless of halide selection,iodide-based(neoPA)_(2)(FA)_((n-1))PbnI_((3n+1))phases are formed above the perovskite substrate,while the added halide anions diffuse and passivate the perovskite bulk.In addition,we also find the halide choice has an influence on the degree of dimensionality(n).Comparing the three halides,we find that chloride-based salts exhibit superior crystallographic,enhanced carrier transport,and extraction compared to the iodide and bromide analogs.As a result,we report high power conversion efficiency in quasi-2D/3D PSCs,which are optimal when using chloride salts,reaching up to 23.35%,and improving long-term stability.
基金
X.L.and T.W.are contributed equally to this work.W.Z.acknowledges the Engineering and Physical Sciences Research Council(EPSRC)New Investigator Award(2018
EP/R043272/1)
Marie Skłodowska-Curie Actions Individual Fellowships(839136)
H.L.acknowledges the Newton Advanced Fellowship(192097)
X.L.acknowledges the financial support from Zhengzhou University Scholarship
T.W thanks the University of Surrey Doctoral College for financial support
S.J.S.gratefully acknowledges the support of EPSRC(UK)under grant number EP/N021037/1
L.D.thanks the China Scholarship Council and the Cambridge Trusts for funding
R.C.K.and J.A.S.thank the company Xenocs for their ongoing support through the X-ray scattering user program at the University of Sheffield and the EPSRC for funding the purchase of this instrument
Z.W.,Y.S.,and G.S.thank the financial support from Zhengzhou Materials Genome Institute
S.D.S.and K.J.acknowledge the Royal Society for funding。
