Highly Efficient and Stable CsPbTh₃ (Th = I, Br, Cl) Perovskite Solar Cells by Combinational Passivation Strategy

Abstract

The distorted lead iodide octahedra of all‐inorganic perovskite based on triple halide‐mixed CsPb(I2.85Br0.149Cl0.001) framework have made a tremendous breakthrough in its black phase stability and photovoltaic efficiency. However, their performance still suffers from severe ion migration, trap‐induced nonradiative recombination, and black phase instability due to lower tolerance factor and high total energy. Here, a combinational passivation strategy to suppress ion migration and reduce traps both on the surface and in the bulk of the CsPhTh3 perovskite film is developed, resulting in improved power conversion efficiency (PCE) to as high as 19.37%. The involvement of guanidinium (GA) into the CsPhTh3 perovskite bulk film and glycocyamine (GCA) passivation on the perovskite surface and grain boundary synergistically enlarge the tolerance factor and suppress the trap state density. In addition, the acetate anion as a nucleating agent significantly improves the thermodynamic stability of GA‐doped CsPbTh3 film through the slight distortion of PbI6 octahedra. The decreased nonradiative recombination loss translates to a high fill factor of 82.1% and open‐circuit voltage (VOC) of 1.17 V. Furthermore, bare CsPbTh3 perovskite solar cells without any encapsulation retain 80% of its initial PCE value after being stored for one month under ambient conditions.

Enhancement of All-Inorganic Perovskite Solar Cells by Lead–Cerium Bimetal Strategy

“…The CsPb 0.85 Ce 0.1 I 3 PSCs exhibit a better conversion of incident photons and current density than CsPbI 3 PSCs, and the integrated J sc and EQE are consistent with PV parameters in Table , which verify that J – V measurements are well-calibrated. The EQE cutoff edge is well-consistent with the UV–vis absorption curve at 750 nm in Figure f Figure b shows the trap-filled limited voltage ( V TFL ) with electron-only devices under dark I – V measurements.…”

“…Owing to different sizes and electronegativity of Ce and Pb, the atomic spacing of CsPb x Ce 0.67(1– x ) I 3 could be changed with the location of CsPbI 3 . A distorted lower-symmetry perovskite structure is formed with the partially substituting of Pb using Ce, as shown in Figure and Figure S1. ,, Figure S1 indicates that CeI 3 can interact with CsI 2 , forming a Cs 3 Ce 2 I 9 perovskite structure. It means that Ce 3+ has a similar function with Pb 2+ .…”

“…19 A distorted lowersymmetry perovskite structure is formed with the partially substituting of Pb using Ce, as shown in Figure 1 and Figure S1. 20,33,34 Figure S1 indicates that CeI 3 can interact with CsI 2 , forming a Cs 3 Ce 2 I 9 perovskite structure. It means that Ce 3+ has a similar function with Pb 2+ .…”

Synchronous Surface Reconstruction and Defect Passivation for High‐Performance Inorganic Perovskite Solar Cells

“…The improvement of crystallinity with NaDDTC is well agreement with the change of grain morphology as revealed in the SEM images. [45] The influence of NaDDTC on the crystal morphology can be also characterized by atomic force microscopy (AFM). The NaDDTC-passivated film shows smoother, with a small amount of scattered particles, and the roughness is reduced to 9.26 nm (Figure 2g,h).…”

Organic Molecules in All‐Inorganic CsPbIxBr3−xPerovskite Solar Cells: Interface Modifiers or Precursor Additives

“…[ 39 ] The glycocyamine (GCA) was used as a surface termination agent to modify grain boundaries, passivate defects in the interface, improve τ values, and stabilize the α‐phase. [ 40 ] The stability and efficiency of PSCs depend on the interface adjustment mechanism of perovskite thin films. As illustrated in Figure 1j,k, multifunctional S‐benzyl isothiourea hydrochloride (SBTCl) was used to strengthen and passivate excess PbI 2 on CsPbIBr 2 film.…”