Abstract
In this thesis, I study on the carrier transporting layers and perovskite composition of organometallic perovskite solar cells. In the first chapter, I briefly review the development of modern photovoltaics and organometallic perovskite solar cells. In the second chapter, the operation principle and characteristics of organometallic perovskite solar cells are described, followed by the details of device structures, materials analyses, device fabrications and characteristics measurements. In the third chapter, different hole transporting layers (HTLs) used in organometallic perovskite solar cells are studied. By optimizing the composition of HTL solution and fabrication methods, the device using 2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9’-spirobifluorene (spiro-OMeTAD) as HTL delivers the highest power conversion efficiency (PCE) of 14.6 %, with a short circuit current density (Jsc) of 22.50 mA/cm2, an open circuit voltage (Voc) of 1.05 V and a fill factor (F.F.) of 0.62. In the forth chapter, I use in-house synthesized TiO2 nanoparticle and commercial compact TiO2 as electron transporting layers (ETLs). After the optimization of devices, the one using TiO2 nanoparticle as ETL gives the highest PCE of 13.2 %, with Jsc of 21.28 mA/cm2, Voc of 1.0 V and F.F. of 0.62. In the fifth chapter, the composition of perovskite absorbing layers is studied. By replacing methylammonium (CH3NH3+, MA+) with formamidinium (HN=CHNH3+, FA+) and fine-tuning the molar ratios of halogen, the optimized device shows the highest PCE of 13.2 %, with Jsc of 21.28 mA/cm2, Voc of 1.0 V and F.F. of 0.62. In the sixth chapter, two-step process is used for the device frabrication, and the best device can deliver a PCE of 13.0 %, with Jsc of 18.86 mA/cm2, Voc of 1.04 V and F.F. of 0.67.