| 초록 |
The most extensively used perovskite absorber is methylammonium lead iodide (MAPbI3). Defects types and quantities, especially for the defects involved A-site cation (MA+), seems to have significant influence on the materials properties and further on the solar cells performance. In this report, a new strategy to enhance the photovoltaic performance of perovskite solar cells has been developed, by introducing smaller size potassium cation (K+) into the lattice structure of MAPbI3. X-ray diffraction data indicate that the K+ mainly occupied the interstitial position in perovskite crystal lattice. Systematic study has demonstrated that there are several benefits by adding proper amount K+ to MAPbI3. The increased crystallinity, crystal size and decreased surface potential result in eminent carrier separation properties and thus reduce the charge recombination in solar cell devices. The optimized substitution range has been investigated, when x=0.2, the modified perovskite presents balanced injection capacity for both holes and electrons, and a conversion efficiency over 17 % has been obtained. |
