Optoelectrical Properties of Hexamine Doped-Methylammonium Lead Iodide Perovskite under Different Grain-Shape Crystallinity

The crystallinity properties of perovskite influence their optoelectrical performance in solar cell applications. We optimized the grain shape and crystallinity of perovskite film by annealing treatment from 130 to 170 degrees C under high humidity (relative humidity of 70%). We found that the grain size, grain interface, and grain morphology of the perovskite are optimized when the sample was annealed at 150 degrees C for 1 h in the air. At this condition, the perovskite film is composed of 250 nm crystalline shape grain and compact inter-grain structure with an invincible grain interface. Perovskite solar cells device analysis indicated that the device fabricated using the samples annealed at 150 degrees C produced the highest power conversion efficiency, namely 17.77%. The open circuit voltage (V-oc), short-circuit current density (J(sc)), and fill factor (FF) of the device are as high as 1.05 V, 22.27 mA/cm(2), and 0.76, respectively. Optoelectrical dynamic analysis using transient photoluminescence and electrochemical impedance spectroscopies reveals that (i) carrier lifetime in the champion device can be up to 25 ns, which is almost double the carrier lifetime of the sample annealed at 130 degrees C. (ii) The interfacial charge transfer resistance is low in the champion device, i.e., similar to 20 Omega, which has a crystalline grain morphology, enabling active photocurrent extraction. Perovskite's behavior under annealing treatment in high humidity conditions can be a guide for the industrialization of perovskite solar cells.

Automated summary

The crystalline properties of perovskite film were optimized through annealing treatment under high humidity conditions. The resulting perovskite solar cells exhibited a power conversion efficiency of 17.77%, with a carrier lifetime of 25 ns and low interfacial charge transfer resistance. These findings provide guidance for the industrialization of perovskite solar cells.