Investigation of phonon scattering in superlattices for design of efficient multiple quantum-well hot carrier solar cells

研究超晶格中的声子散射，以设计高效的多量子阱热载流子太阳能电池

• 批准号: 2115067
• 负责人: Jivtesh Garg
• 金额: $ 10.71万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2115067&HistoricalAwards=false
• 关键词: Investigation; phonon; scattering; superlattices; design

The hot carrier solar cell is a type of solar energy converter that captures the excess thermal energy of photo-generated electrons and holes in a semiconductor to produce electric power. Hot carrier solar cells hold the promise of yielding significantly higher efficiency beyond traditional limits. A promising material system for achieving high efficiency hot carrier solar cells involves multiple quantum wells, comprised of semiconductor materials arranged in alternating layers known as superlattices, to effectively diminish energy loss from hot electrons. Energy loss from electrons occurs by dissipation of energy to high energy lattice vibrations, which further dissipate to low energy lattice vibrations by scattering. Decoupling the high energy from low energy lattice vibrations by minimizing scattering can ultimately enhance the solar cell efficiency. In the proposed research, the project team will tackle this challenge and design high-efficiency hot carrier solar cells through engineering the superlattice composition and by straining the semiconductor crystal. A dominant phonon scattering mechanism in semiconductors is the Klemens channel, which involves decay of an optical phonon into two acoustic phonons. By modifying superlattice composition, the energy gap in the phonon dispersion can be modified providing avenues to suppress Klemens like channels in phonon scattering. This can enable longer phonon lifetimes, resulting in non-equilibrium phonon populations, thus facilitating hot phonon bottleneck in the thermalization of electrons. Strain can similarly modify phonon dispersion, again allowing for the possibility to diminish phonon scattering. The role of superlattice composition and strain will be studied in two superlattice systems - InAs/AlSb and AlAs/GaAs. Analysis will be performed through a first-principles approach by using harmonic and anharmonic force interactions derived from density-functional theory along with a solution of the phonon Boltzmann transport equation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

热载流子太阳能电池是一种太阳能转换器，它捕获半导体中光生电子和空穴的多余热能来产生电力。热载流子太阳能电池有望产生超越传统限制的显着更高的效率。用于实现高效热载流子太阳能电池的一种有前景的材料系统涉及多个量子阱，由排列在称为超晶格的交替层中的半导体材料组成，以有效减少热电子的能量损失。电子的能量损失是通过将能量耗散至高能晶格振动而发生的，该能量通过散射进一步耗散至低能晶格振动。通过最大限度地减少散射，将高能与低能晶格振动解耦，最终可以提高太阳能电池的效率。在拟议的研究中，项目团队将应对这一挑战，并通过设计超晶格成分和应变半导体晶体来设计高效热载流子太阳能电池。半导体中主要的声子散射机制是克莱门斯通道，其中涉及光学声子衰变成两个声声子。通过改变超晶格成分，可以改变声子色散中的能隙，从而提供抑制声子散射中的克莱门斯样通道的途径。这可以实现更长的声子寿命，导致非平衡声子群体，从而促进电子热化中的热声子瓶颈。应变可以类似地改变声子色散，再次允许减少声子散射的可能性。将在两种超晶格系统（InAs/AlSb 和 AlAs/GaAs）中研究超晶格成分和应变的作用。将使用从密度泛函理论导出的谐波和非谐波力相互作用以及声子玻尔兹曼输运方程的解，通过第一性原理方法进行分析。该奖项反映了 NSF 的法定使命，并通过使用以下方法进行评估被认为值得支持：基金会的智力价值和更广泛的影响审查标准。

项目成果

Length dependence thermal conductivity of zinc selenide (ZnSe) and zinc telluride (ZnTe) – a combined first principles and frequency domain thermoreflectance (FDTR) study

硒化锌 (ZnSe) 和碲化锌 (ZnTe) 的长度依赖性热导率 — 结合第一原理和频域热反射 (FDTR) 研究

• DOI: 10.1039/d2cp03612f
• 发表时间: 2022-12
• 期刊: Physical Chemistry Chemical Physics
• 影响因子: 3.3
• 作者: Muthaiah, Rajmohan;Annam, Roshan Sameer;Tarannum, Fatema;Gupta, Ashish Kumar;Garg, Jivtesh;Arafin, Shamsul
• 通讯作者: Arafin, Shamsul