Performance improvement of perovskite solar cells through enhanced hole extraction: The role of iodide concentration gradient

By Ming Wang, Zhigang Zang, Bo Yang, Xiaofei Hu, K. Sun, Lidong Sun. Solar Energy Materials and Solar Cells, 2018

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Abstract Realization of fast hole extraction is an effective route for the performance enhancement of inverted perovskite solar cells (PSCs). The precise bandgap tuning in perovskite layer has been expected to accelerate hole extraction. Therefore, in this report, we demonstrate a modified one-step fabrication method for the bandgap tuning of perovskite layer by designing iodide concentration gradient. Prior to the perovskite precursor solution spin-coated, different concentration of methanaminium iodide (MAI) solution was pre-coated on PEDOT:PSS layer to form iodide concentration gradient in perovskite layer. Fast hole extraction and short lifetime due to iodide concentration gradient was confirmed by photoluminescence measurement. By optimizing the MAI concentration with 4 mg/ml, the modified PSCs exhibited a power conversion efficiency of 16.67% due to an increase in short-circuit current density (Jsc) from 19.66 mA/cm2 to 23.52 mA/cm2 and an increase in open circuit voltage from 0.97 V to 1.01 V. These values are significantly higher than PSCs using conventional one-step fabrication method without pre-coated MAI layer, which exhibit efficiency of only 14.8%. We think that this new approach is an effective way to enhance the performance of PSCs.

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/f634783f5d4ac722ac82bb605268daa7a003f825