Grain-Boundary Engineering in Hybrid Organic-Inorganic Perovskites
Abstract
Grain-Boundary Engineering in Hybrid Organic-Inorganic Perovskites Abstract Perovskite solar cells (PSCs) based on hybrid organic-inorganic perovskites (HOIPs) are attracting a great deal of interest. This is primarily because they offer unprecedented promise of low-cost solution-processed photovolatics (PVs) that have over 22% power conversion efficiency (PCE). PSCs are also very promising for addressing the need for lightweight, flexible, and portable PVs for distributed and individualized power supply in military and civilian applications. Grain boundaries are ubiquitous in polycrystalline HOIP thin films at the heart of PSCs, and there is tantalizing evidence to suggest that the nature of the grain boundaries in HOIPs is unprecedented and unique. Also, there is sufficient evidence to indicate that the grain boundaries are key to determining the properties of the HOIP thin films and, in turn, the performance of the PSCs made from these films. However, compared with conventional inorganic PV materials, little is known about HOIP grain boundaries and their effects on PSCsrelevant properties. This is primarily because HOIPs are an unusual family of materials that defy classical classification (metals, ceramics, or polymers) and fall into the hitherto uncharted territory between conventional ‘soft’ materials and ‘hard’ crystalline materials. Thus, the broad goal of the proposed research is to provide a scientific platform for the engineering of HOIP grain boundaries, aimed at rational tailoring of HOIP microstructures for the desired properties relevant to PSCs. The first objective is to gain deep understanding of the nature of the grains and the unique characteristics of grain boundaries in polycrystalline HOIPs using innovative characterization techniques. The second objective is to understand the fundamental influence of grain boundaries on the important properties of HOIPs relevant to PSCs through systematic experimentation. The third objective is to use this basic understanding for engineering grain boundaries using novel approaches (synthesis, processing, doping) for enhanced PSCs-relevant properties, such as optical absorption/emission, carrier mobility/lifetime, and thermal/environmental stability. The results from this proposed research are likely to have far-reaching impact on achieving desired HOIP microstructures in low-cost, high-efficiency PSCs of the future. A comprehensive research program is proposed, one aimed at achieving the above three main objectives, through the following interrelated tasks and subtasks: (i) processing of a variety of HOIP thin film compositions with diverse set of grain boundaries features and characteristics, including crystal-misorientation, grain-boundary orientation, texture, and chemistry; (ii) extensive microscopic, spectroscopic, and analytical characterization of the grain boundaries; (iii) studies of grain-boundary dynamics; (iv) measurement of PSCs-relevant properties, including optical absorption, carrier dynamics, ion migration, thermal stability, and environmental stability; (v) in operando functional microscopy; (vi) PSCs fabrication, and performance and stability evaluation; and (vii) tailoring of HOIP grain boundaries and microstructures. At the end of the proposed project we will have answered the following basic questions. (a) How are grain boundaries in HOIPs so unique and why? (b) What is the scientific basis for the influence of HOIP grain boundaries on their important PSCs-relevant properties? (c) How can we rationally design and engineer HOIP grain boundaries for maximizing the desired combination of properties for next-generation PSCs?
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2017
- Source ID
- N000141712232
Entities
People
- Nitin P Padture
Organizations
- Brown University
- Office of Naval Research
- United States Navy