Gyawali Sunil, Tirumala Ravi Teja A, Loh Harrison, Andiappan Marimuthu, Bristow Alan D
Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, United States.
School of Chemical Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
J Phys Chem C Nanomater Interfaces. 2024 Jan 24;128(5):2003-2011. doi: 10.1021/acs.jpcc.3c06941. eCollection 2024 Feb 8.
Inversion analysis of transient absorption data to capture the photoexcited charge carrier population rate dynamics is a powerful technique for extracting realistic lifetimes and identifying recombination pathways. However, for highly scattering samples such as CuO nanoparticles (NPs) with associated dielectric Mie scattering, the scattering leads to an inaccurate measure of the excited photocarrier. This work studies methods to correct for the scattering to generalize the use of inversion analysis and provide secondary information about the nature of the scattering NPs. Scattering profiles of semitransparent disks containing CuO NPs with different shapes and sizes are measured to demonstrate that the inclusion of scattering in analysis reduces the photoexcited carrier density by 1 order of magnitude. It is found that the photocarrier density response is affected by shape rather than size. A Fourier transform of the scattering profiles produces a distribution of length scales within the sample characteristic of the mean separation of scatterers. This analysis reveals that NPs are forming clusters. Links are made between the scattering and carrier dynamics.
对瞬态吸收数据进行反演分析以获取光激发电荷载流子的种群速率动态，是一种用于提取实际寿命和识别复合途径的强大技术。然而，对于诸如具有相关介电米氏散射的氧化铜纳米颗粒（NPs）等高度散射的样品，散射会导致对激发光载流子的测量不准确。这项工作研究了校正散射的方法，以推广反演分析的应用，并提供有关散射纳米颗粒性质的二级信息。测量了包含不同形状和尺寸的氧化铜纳米颗粒的半透明圆盘的散射轮廓，以证明在分析中考虑散射会使光激发载流子密度降低1个数量级。研究发现，光载流子密度响应受形状而非尺寸的影响。散射轮廓的傅里叶变换产生了样品内长度尺度的分布，其特征是散射体的平均间距。该分析表明纳米颗粒正在形成簇。建立了散射与载流子动力学之间的联系。
