Bombsch Jakob, Avancini Enrico, Carron Romain, Handick Evelyn, Garcia-Diez Raul, Hartmann Claudia, Félix Roberto, Ueda Shigenori, Wilks Regan G, Bär Marcus
Interface Design, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin 14109, Germany.
Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland.
ACS Appl Mater Interfaces. 2020 Aug 5;12(31):34941-34948. doi: 10.1021/acsami.0c08794. Epub 2020 Jul 21.
The underlying beneficial mechanism of heavy alkali postdeposition treatment (PDT) of Cu(In,Ga)Se thin-film solar cell absorbers that led to new record efficiencies in recent years is studied using photoelectron spectroscopy. Excitation energies between 40.8 eV and 6 keV were used to examine the near-surface region of Cu(In,Ga)Se thin-film solar cell absorbers that underwent NaF and combined NaF/RbF PDT. The already Cu-deficient surface region after NaF PDT, which is modeled as a Cu:(In + Ga):Se = 1:5:8 phase, shows further depletion after NaF/RbF PDT and seems to incorporate some Rb. Additionally, we have found strong indications for the NaF/RbF PDT-induced formation of a Rb-In-Se-type compound with a 1:1:2 stoichiometry partially covering the absorber surface. The electronic Cu(In,Ga)Se structure is modified due to the RbF treatment, with a pronounced shift in the valence band maximum away from the Fermi level in the immediate vicinity of the surface.
利用光电子能谱研究了近年来使铜铟镓硒（Cu(In,Ga)Se）薄膜太阳能电池吸收层的重碱后沉积处理（PDT）取得新的记录效率的潜在有益机制。使用40.8电子伏特至6千电子伏特之间的激发能量来检测经过NaF以及NaF/RbF组合PDT处理的Cu(In,Ga)Se薄膜太阳能电池吸收层的近表面区域。NaF PDT处理后已经贫铜的表面区域，其模型为Cu:(In + Ga):Se = 1:5:8相，在NaF/RbF PDT处理后显示出进一步的贫化，并且似乎掺入了一些铷。此外，我们发现了强烈迹象，表明NaF/RbF PDT诱导形成了一种化学计量比为1:1:2的Rb-In-Se型化合物，部分覆盖了吸收层表面。由于RbF处理，Cu(In,Ga)Se的电子结构发生了改变，在表面紧邻区域价带最大值明显远离费米能级。
