CuSbSe 2[15] solar cells were also rapidly developed with PCE over 4%. However, caused by asymmetric atom coordination, the LDCS materials exhibit significantly anisotropic carrier transport in different orientations (Figure 1a,b). Along the covalent bond direction (the chain and the layer directions of 1D and 2D materials, respectively), the overlapping electron clouds are beneficial to the carrier transport ( Figure 1c, right part). Whereas, the carriers have to undergo interchain or interlayer barriers when transport perpendicular to covalent bond directions (Figure 1c, left part). [6a] Typically, the anisotropic factor of mobility, conductivity or effective mass of LDCS materials can reach 10-100 in different directions. [16] At present, orientation control is an urgent problem for LDCS-based semiconductor devices.However, ruled by the minimum energy principle, orientation control is intrinsically difficult for LDCS materials. In brief, materials are prone to grow with low-energy crystal faces parallel to the substrates when deposited under an equilibrium state. For LDCS materials, the crystal faces parallel to the direction of van der Waals (vdW) force (e.g., the side faces of 1D materials and layer faces of 2D materials) always demonstrate lower surface energy than those along covalent bond directions (Table S1, Supporting Information). [6a,17] Therefore, the chains or layers are prone to lying on the substrates, implying photogenerated carriers must hop against interchain or interlayer barriers from the bottom electrode to top electrode (Figure 1a-c), causing transport difficulty. The dependence of orientation on the PCE of solar cells are solidly verified by Sb 2 Se 3 , CuSbSe 2 and SnS solar cells, even the low-dimensional organic-inorganic hybrid perovskite solar cells (e.g., quasi-2D (MAPbI 3 ) 3 BA 2 PbI 4 , here MA = CH 3 NH 3 + , BA = C 4 H 13 NH 3 + ). [18] Generally, the suitable orientation ([hkl, l ≠ 0] orientations for 1D materials and [hk0] orientations for 2D materials, where we define Miller indices l of 1D and 2D materials is along the chain direction and perpendicular to the layers, respectively) is able to promote the carrier collection and reduce the series resistance of solar cells, resulting in the improvement of photocurrent and fill factor (FF) of LDCS-based solar cells.In 2015, the preferentially [211]-and [221]-oriented Sb 2 Se 3 solar cells were fabricated on CdS buffer layer through The orientation of low-dimensional crystal-structural (LDCS) films significantly affects the performance of photoelectric devices, particularly in vertical conducting devices such as solar cells and light-emitting diodes. According to film growth theory, the initial seeds determine the final orientation of the film. Ruled by the minimum energy principle, lying (chains or layers parallel to the substrate) seeds bonding with the substrate through van der Waals forces are easier to form than standing (chains or layers perpendicular to the substrate) seeds bonding with the substrate by a covalent bond. ...