Manousakis Efstratios
Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32306-4350, USA.
Department of Physics, University of Athens, Panepistimioupolis, Zografos, 157 84, Athens, Greece.
Sci Rep. 2019 Dec 31;9(1):20395. doi: 10.1038/s41598-019-56974-y.
A mechanism for multiple carrier generation through impact ionization (IA) proposed earlier for bulk systems of strongly correlated insulators is generalized to the case of conventional insulators that contain localized bands a few eV above and below the highest occupied band. Specifically, we study the case of hybridization of localized orbitals with more dispersive bands near the Fermi level, where the generated multiple carriers, which ultimately decay to the edges of the dispersive bands by means of IA processes, acquire lighter mass and this could allow their more efficient separation before recombination. We argue that this may be applicable to the case of halide perovskites and it could be one of the reasons for their observed photovoltaic efficiency. We discuss the criteria one should use to uncover the appropriate material in order to harvest the optimum effect of IA for the spectrum of the solar photon energy distribution.
一种先前为强关联绝缘体的体系统提出的通过碰撞电离（IA）产生多个载流子的机制，被推广到传统绝缘体的情况，这些传统绝缘体在最高占据能带之上和之下几电子伏特处包含局域能带。具体而言，我们研究了局域轨道与费米能级附近更具色散性的能带的杂化情况，在这种情况下，产生的多个载流子最终通过IA过程衰减到色散能带的边缘，获得更轻的质量，这可能使它们在复合之前能更有效地分离。我们认为这可能适用于卤化物钙钛矿的情况，并且这可能是它们观测到的光伏效率的原因之一。我们讨论了为了在太阳光子能量分布光谱中收获IA的最佳效果，人们应该用来发现合适材料的标准。
