Chemistry, Electrical and Computer Engineering, Physics and Astronomy, Ames Laboratory, Microelectronics Research Center (MRC)
Journal or Book Title
Using time-resolved laser-scanning confocal microscopy and ultrafast optical pump/THz probe spectroscopy, we measure photoluminescence and THz-conductivity in perovskite micro-crystals and films. Photoluminescence quenching and lifetime variations occur from local heterogeneity. Ultrafast THz-spectra measure sharp quantum transitions from excitonic Rydberg states, providing weakly bound excitons with a binding energy of ~13.5 meV at low temperatures. Ab-initio electronic structure calculations give a direct band gap of 1.64 eV, a dielectric constant ~18, heavy electrons, and light holes, resulting in weakly bound excitons, consistent with the binding energies from experiment. The complementary spectroscopy and simulations reveal fundamental insights into perovskite light-matter interactions.
Materials Research Society
Liu, Zhaoyu; Bhamu, K. C.; Luo, Liang; Shah, Satvik; Park, Joong-Mok; Cheng, Di; Long, Men; Biswas, Rana; Fungara, F.; Shinar, Ruth; Shinar, Joseph; Vela, Javier; and Wang, Jigang, "Spatial–temporal spectroscopy characterizations and electronic structure of methylammonium perovskites" (2018). Chemistry Publications. 1037.