▎ 摘　　要

Opening the graphene zero bandgap and simultaneously keeping its linear electronic dispersion has been widely accepted as a very challenging scientific puzzle. Moreover, one of the biggest obstacles for all-perovskite tandem solar cells is the lack of perovskite semiconductors with a narrow bandgap (<1.2 eV). Here we examine these two issues and theoretically identify the environmentally friendly perovskite A(2)HfTe(4) (A = Ca, Sr, Ba), especially Ba2HfTe4 . This material is a good candidate for three-dimensional graphene-like semiconductors with two-dimensional electronic dimensionality, linear band-edge dispersion, a direct bandgap of 0.77-0.96 eV, carrier effective mass and mobility similar to graphene, visiblelight absorption beyond Pb-based perovskites, and power conversion efficiency approaching similar to 28%. A(2)HfTe(4) is a promising bottom-cell material that helps achieve all-perovskite tandem solar cells thanks to its narrow bandgap and acts as a potential alternative to the currently popular perovskite-silicon tandem solar cells.