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：晶体硅太阳能电池技术由于其在半导体电子领域的广泛应用，多年来一直主导着光伏技术市场，目前的市场份额为90%。有限光谱范围内的光吸收和热化损耗阻碍了硅太阳能电池效率的进一步提高。这项研究的目标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的物理热力学限制。这项研究将执行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。该研究将解决钙钛矿与硅和其他半导体集成的基本限制，并将影响多样化的技术和社会社区。这项研究的广泛影响在于：1)将研究成果纳入田纳西理工大学的光伏工程、物理电子学和光电子工程等课程的课程改进中；2)招募女性、代表性不足的群体和退伍军人参与研究；3)组织外展活动，以提高高中、初中和社区对能源技术的认识。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。技术方面：本研究计划的主要目的在于解决钙钛矿/硅串联技术面临的挑战，如：1)钙钛矿吸收剂的高亚带隙吸收；2)钙钛矿/硅串联光转换效率低；3)反射损耗和寄生损耗较高；4)降低开路电压和填充系数。基于传输矩阵的光吸收、反射和内部量子效率与每层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。将传统的锥体结构与波长选择性中间反射体相结合进行波长相关吸收建模，将进一步提高串联效率。基于掺杂浓度和厚度的电流密度与电压对串联中每个子电池层进行模拟，并优化这些参数以匹配电流，将实现串联设计的最佳光转换效率。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.