Hot carrier extraction from 2D semiconductor photoelectrodes

Hot carrier-based energy conversion systems could double the efficiency of conventional solar energy technology or drive photochemical reactions that would not be possible using fully thermalized, “cool” carriers, but current strategies require expensive multi-junction architectures. Using an unprecedented combination of photoelectrochemical and in situ transient absorption spectroscopy measurements, we demonstrate ultrafast (<50 fs) hot exciton and free carrier extraction under applied bias in a proof-of-concept photoelectrochemical solar cell made from earth-abundant and potentially inexpensive monolayer (ML) MoS2. Our approach facilitates ultrathin 7 Å charge transport distances over 1 cm2 areas by intimately coupling ML-MoS2 to an electron-selective solid contact and a hole-selective electrolyte contact. Our theoretical investigations of the spatial distribution of exciton states suggest greater electronic coupling between hot exciton states located on peripheral S atoms and neig..., Transient absorption data were collected with at 390 nm pump pulse (50 fs) and broadband white light probe pulse. The delay time between the pump and probe was scanned from -1.2 ps to 201 ps. Spectra were imported into Matlab and plotted in contour plots as a function of delay time and wavelength. The spectra are given here in Matlab workspace format (.mat). To fit each exciton peak, the spectrum at each time delay was segmented into the A-exciton region (630 nm – 685 nm), B-exciton region (580 nm – 630 nm), and C-exciton region (413 nm – 460 nm). Each region was fit with a convolution of a gaussian and line to fit the exciton peak and background signal, respectively. The amplitudes of the gaussian fits were plotted as a function of delay time for each exciton. These plots were fit as described in detail in the Supplementary Information. All raw spectral data and processed data are saved in a Matlab workspace and uploaded here.
Potential-dependent absorbance measurements were taken by r..., The data files are Matlab Data workspace files (.mat). Scripts used to process the transient absorption data and the potential-dependent absorbance are Matlab files (.m). Codes used to do BSE-GW calculations are python scripts (.py).Â

基于热载流子的能量转换系统可将传统太阳能技术的效率提升一倍，或是驱动无法通过完全热化的‘冷’载流子实现的光化学反应，但当前相关策略需要成本高昂的多结架构。我们首次结合光电化学与原位瞬态吸收光谱测量手段，在由地球储量丰富、潜在成本低廉的单层（monolayer, ML）二硫化钼（MoS₂）制备的概念验证型光电化学太阳能电池中，证实了外加偏压下超快（<50飞秒）的热激子与自由载流子萃取过程。我们的方法通过将单层二硫化钼与电子选择性固体接触以及空穴选择性电解液接触紧密耦合，实现了面积超过1平方厘米的超短7埃电荷传输距离。我们对激子态空间分布的理论研究表明，位于边缘硫原子上的热激子态与邻近……

瞬态吸收数据采用390纳米泵浦脉冲（50飞秒）与宽带白光探测脉冲采集得到。泵浦与探测脉冲间的延迟时间扫描范围为-1.2皮秒至201皮秒。将光谱导入Matlab后，以延迟时间与波长为变量绘制等高线图。本数据集以Matlab工作区格式（.mat）提供。为拟合每个激子峰，我们将每个时间延迟下的光谱划分为A激子区（630纳米–685纳米）、B激子区（580纳米–630纳米）以及C激子区（413纳米–460纳米）。每个区域分别采用高斯函数与线性函数的卷积进行拟合，以分别对应激子峰与背景信号。将高斯拟合的振幅作为每个激子的延迟时间函数进行绘图，并按照补充材料中详述的方法对这些绘图进行拟合。所有原始光谱数据与处理后数据均保存于Matlab工作区并随本数据集上传。

电势相关吸光度测量通过……[原文未完整表述]。数据文件均为Matlab数据工作区文件（.mat）。用于处理瞬态吸收数据与电势相关吸光度数据的脚本为Matlab文件（.m）。用于进行BSE-GW计算的代码为Python脚本（.py）。