Implementing Dopant-Free Hole-Transporting Layers and Metal-Incorporated CsPbI₂Br for Stable All-Inorganic Perovskite Solar Cells

Abstract

Mixed-halide CsPbI 2 Br perovskite is promising for efficient and thermally stable all-inorganic solar cells; however, the use of conventional antisolvent methods and additives-based hole-transporting layers (HTLs) currently hampers progress. Here, we have employed hot-air-assisted perovskite deposition in ambient condition to obtain high-quality photoactive CsPbI 2 Br perovskite films and have extended stable device operation using metal cation doping and dopant-free hole-transporting materials. Density functional theory calculations are used to study the structural and optoelectronic properties of the CsPbI 2 Br perovskite when it is doped with metal cations Eu 2+ and In 3+ . We experimentally incorporated Eu 2+ and In 3+ metal ions into CsPbI 2 Br films and applied dopant-free copper(I) thiocyanate (CuSCN) and poly(3-hexylthiophene) (P3HT)-based materials as low-cost hole transporting layers, leading to record-high power conversion efficiencies of 15.27% and 15.69%, respectively, and a retention of >95% of the initial efficiency over 1600 h at 85 °C thermal stress.

Dopant‐Free Polymer HTM‐Based CsPbI2Br Solar Cells with Efficiency Over 17% in Sunlight and 34% in Indoor Light

“…Though this performance is much inferior to the target device, it is comparable to the highest efficiency of dopant-free P3HT-based CsPbI 2 Br solar cells. [6] Besides, severe hysteresis, as we observed in the reference device, was also observed in recent work and it was inevitable even with interface engineering. [5] Hence, it was fair to take this P3HT device made by us as a reference for comparison in this study.…”

Tetra-indole core as a dual agent: a hole selective layer that passivates defects in perovskite solar cells

“…16 Inorganic HTMs are promising candidate due to its high stability, however the PCE performance is limited by their surface defects, low intrinsic conductivity, poor solubility in common organic solvents and particle size reproducibility. 17 Whereas, the polymers based HTM display decent morphological properties but low stability and reproducibility, especially when the dopants are used. 18 Compared to the inorganic and polymeric counterparts, small molecules as HTM are viable alternatives owing to high purity and solubility, define molecular structure and good reproducibility.…”

Dopant‐Free Hole Transport Materials Afford Efficient and Stable Inorganic Perovskite Solar Cells and Modules

“…Hence,t he hygroscopic nature of the dopants eliminates the advantage of the hydrophobicity of the upper hole transport layers and significantly accelerates the phase transition of CsPbI 3 leading to device degradation. [16] Therefore,d eveloping dopant-free,efficient, and stable HTMs is highly desirable and could lead to practical applications of inorganic perovskites in PSCs.…”