Two-dimensional (2D) materials and their corresponding van der Waals (vdW) heterostructures are considered as promising candidates for highly efficient solar cell applications. A series of 2D HfX₂ (X = Cl, Br, I) monolayers are proposed, via first-principle calculations. The vibrational phonon spectra and molecular dynamics simulation results indicate that HfX₂ monolayers possess dynamical and thermodynamical stability. Moreover, their electronic structure shows that their Heyd–Scuseria–Ernzerhof(HSE06)-based band values (1.033–1.475 eV) are suitable as donor systems for excitonic solar cells (XSCs). The material’s significant visible-light absorbing capability (∼10⁵ cm⁻¹) and superior power conversion efficiency (∼20%) are demonstrated by establishing a reasonable type II vdW heterostructure. This suggests the significant potential of HfX₂ monolayers as a candidate material for XSCs.

二维（2D）材料及其相应的范德华（vdW）异质结构被认为是高效太阳能电池应用的有希望的候选者。通过第一性原理计算，提出了一系列 2D HfX _{2 (X = Cl, Br, I) 单层。}振动声子光谱和分子动力学模拟结果表明HfX ₂单分子层具有动力学和热力学稳定性。此外，它们的电子结构表明，它们基于 Heyd-Scuseria-Ernzerhof（HSE06）的能带值（1.033-1.475 eV）适合作为激子太阳能电池（XSC）的供体系统。该材料显着的可见光吸收能力（~ ^{10 5} cm ^-1) 和优异的功率转换效率 (~20%) 通过建立合理的 II 型 vdW 异质结构得到证明。这表明 HfX ₂单层作为 XSC 的候选材料具有巨大的潜力。