Research Area

Hybrid organic-inorganic perovskite materials, expressed as ABX₃ where a monovalent cation (such as methylammonium (CH₃NH₃⁺), formamidinium (CH(NH₂)₂⁺), and Cesium (Cs⁺)) are located at A site, Sn or Pb is located at B site, and halide (I^–/Br^–/Cl^–) is placed at X site, have been attained a lot of attention for their photovoltaic applications. Perovskite materials have great properties as high absorption coefficient, tunable bandgap, low exciton binding energy and long carrier diffusion length, thereby perovskite solar cells (PSCs) are now exhibiting greatly high power conversion efficiencies up to 24.2 % which is comparable performance to conventional polycrystalline Silicon photovoltaics. Though PSCs are close to Si photovoltaics, they still have some drawbacks as their humid/thermal instability, small scale and use of toxic Pb materials. Especially, long-term stability and large-area production should be achieved to take over Si photovoltaics role as a primary conventional solar cell.

So far, we achieved to elucidate the working mechanisms of hole transport materials and degradation process of PSCs. With the help of advanced characterizations like FIB-TEM, APT, and STEM-EELS, we were able to deeply understand their charge transfer and recombination mechanisms. Based on previous researches, we are now aiming for the commercialization of PSCs by scaling up and enhancing long-term stability of the PSCs. Device encapsulation or compositional engineering can provide better stability of PSCs and by developing efficient large-area producing method rather than spin-coating method, we can achieve large-area production of PSCs.

Highlighted Publications

1. M. Kim, S. Ham, D. Cheng, T. A. Wynn, H. S. Jung and Y. S. Meng, “Advanced Characterization Techniques for Overcoming Challenges of Perovskite Solar Cell Materials“, Adv. Energy Mater. 2020, 2001753

2. S. Wang, A. Cabreros, Y. Yang, A. S. Hall, S. Valenzuela, Y. Luo, J. Correa-Baena,  M. Kim, Ø. Fjeldberg, D. P. Fenning and Y. S. Meng, “Impacts of the Hole Transport Layer Deposition Process on Buried Interfaces in Perovskite Solar Cells“, Cell Reports Physical Science, 2020, 1, 100103

3. S. Wang, Z. Huang, X. Wang, Y. Li, M. Günther, S. Valenzuela, P. Parikh, A. Cabreros, W. Xiong, and Y. S. Meng “Unveiling the Role of tBP−LiTFSI Complexes in Perovskite Solar Cells” J. Am. Chem. Soc 2018, 140 (48), 16720

4. S. Wang, M. Sina, P. Parikh, T. Uekert, B. Shahbazian, A. Devaraj, and Y. S. Meng, “Role of 4-tert-Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells” Nano Letters, 2016, 16, 5594

5. S. Wang, W. Yuan, and Y. S. Meng. “Spectrum-Dependent Spiro-OMeTAD Oxidization Mechanism in Perovskite Solar Cells“, ACS Appl. Mater. Interfaces, 2015, 7 (44), 24791