EAGER: Investigating Optical Characteristics, Doping Levels and Current Matching in Perovskite/Si, Perovskite/GaAs/Si and Perovskite/III-V Ternary Semiconductors

摘要：非技术性：晶体硅太阳能电池技术多年来一直主导着光伏技术市场，目前市场占有率为90%，这是因为它在半导体电子中的广泛技术应用。有限光谱范围的光吸收和热损失阻碍了硅太阳能电池效率的进一步提高。这项研究的目的是通过串联不同的带隙半导体来提高效率，超越单结硅太阳能电池物理施加的热力学限制。这项研究将实施光学和电子优化方案，以提高太阳能电池、发光二极管和其他电子设备的吸收、光电流和效率。这项研究将解决钙钛矿与硅和其他半导体集成的根本限制，并将影响不同的技术和社会社区。这项研究的更广泛影响在于1)将研究成果纳入田纳西理工大学光伏工程、物理电子学和光电子工程等课程的强化课程；2)招募女性、代表性不足的群体和退伍军人参与研究；3)组织外联活动，在高中、中学和社区各级培养对能源技术的更高认识。这将有助于增加工程和计算机教育的长期入学人数，为整个社会带来许多长期的好处。技术：该研究计划的主要学术意义在于解决钙钛矿/硅串联技术所面临的挑战，例如：1)钙钛矿/硅吸收体子带隙吸收高；2)钙钛矿/硅串联的光转换效率低；3)相对较高的反射和寄生损耗；以及4)开路电压和填充因子的折衷。基于传输矩阵的光学吸收、反射和内部量子效率随波长的优化将提供关于每层可实现的最大吸收效率和光电流的见解。将传统的金字塔结构与波长选择性的中间反射层相结合，建立与波长相关的吸收模型，将进一步提高串接效率。基于掺杂浓度和厚度的电流密度与串联中每个子单元层的电压的模拟，并优化这些参数以匹配电流，将为串联设计实现可能的最佳光电转换效率。这项研究将对固态照明、激光和薄膜电子器件的应用做出重大贡献。

Abstract: Nontechnical: Crystalline silicon solar cell technology has dominated the photovoltaic technology market for years with a current market share of 90%, owing to its wide technological applications in semiconductor electronics. Light absorption for limited range of the spectrum and thermalization losses hinder further increase in silicon solar cell efficiency. This research endeavor is geared toward increasing efficiency beyond the thermodynamic limits imposed by the physics of single-junction silicon solar cells by incorporation of different bandgap semiconductors in tandem. This research will perform optical and electronic optimization schemes to improve absorption, photocurrent and efficiency in solar cells, light emitting diodes and other electronic devices. The research will address fundamental limitations of integration of perovskites with silicon and other semiconductors and will impact a diverse technical and societal community. The broader impacts of this research lies in 1) incorporating research findings into curriculum enhancement of courses such as Photovoltaic Engineering, Physical Electronics and Optoelectronic Engineering at Tennessee Tech University, 2) recruiting female, underrepresented groups and veterans in research and 3) organizing outreach activities to foster increased awareness of energy technologies at the high-school, middle-school and community levels. This will help increase longer-term enrollment in engineering and computing education, yielding many long-standing benefits to society at large. Technical: The primary scholarship of the research plan lies in addressing the challenges facing perovskite/Si tandem technologies such as: 1) high sub-bandgap absorption in the perovskite absorber; 2) low photoconversion efficiency of perovskite/Si tandem; 3) relatively higher reflection and parasitic losses; and 4) compromising open-circuit voltage and fill factor. Transfer-matrix based optimization of optical absorption, reflection and internal quantum efficiency vs. wavelength of each layer will provide insights about maximum achievable absorption efficiency and photocurrent in each layer. Modeling of wavelength-dependent absorption by combining conventional pyramidal texture with wavelength-selective intermediate reflector will further increase the tandem efficiency. Doping concentration and thickness based current density vs. voltage simulations for each subcell layer in the tandem and optimizing those parameters to match the current will achieve the best possible photoconversion efficiency for tandem designs. This research will have significant contributions to solid-state lighting, lasing and thin-film electronic device applications.