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Rational Design of Novel Halide Perovskites Combining Computations and Experiments


Type

Thesis

Change log

Abstract

The perovskite family of materials is extremely large and provides a template for designing materials for different purposes. Among them, hybrid organic-inorganic perovskites (HOIPs) are very interesting and have been recently identified as possible next generation light harvesting materials because they combine low manufacturing cost and relatively high power conversion efficiencies (PCEs). In addition, some other applications like light emitting devices are also highly studied. This thesis starts with an introduction to the solar cell technologies that could use HOIPs. In Chapter 2, previously published results on the structural, electronic, optical and mechanical properties of HOIPs are reviewed in order to understand the background and latest developments in this field. Chapter 3 discusses the computational and experimental methods used in the following chapters. Then Chapter 4 describes the discovery of several hybrid double perovskites, with the formula (MA)2MIMIIIX6 (MA = methylammonium, CH3NH3, MI = K, Ag and Tl, MIII = Bi, Y and Gd, X = Cl and Br). Chapter 5 presents studies on the variable presure and temperature response of formamidinium lead halides FAPbBr3 (FA = formamidinium, CH(NH2)2) as well as the mechanical properties of FAPbBr3 and FAPbI3, followed by a computational study connecting the mechanical properties of halide perovskites ABX3 (A = K, Rb, Cs, Fr and MA, X = Cl, Br and I) to their electronic transport properties. Chapter 6 describes a study on the phase stability, transformation and electronic properties of low-dimensional hybrid perovskites containing the guanidinium cation GuaxPbIx+2 (x = 1, 2 and 3, Gua = guanidinium, C(NH2)3). The conclusions and possible future work are summarized in Chapter 7. These results provide theoreticians and experimentalists with insight into the design and synthesis of novel, highly efficient, stable and environmentally friendly materials for solar cell applications as well as for other purposes in the future.

Description

Date

2018-09-08

Advisors

Bristowe, Paul David
Cheetham, Anthony Kelvin

Keywords

Perovskites, Hybrid Perovskites, Materials Discovery, Materials Design, Density Functional Theory, DFT, Synthesis, X-ray Diffraction, Crystallography, Photovoltaics, Optoelectronics, Mechanical Properties, Phase Stability

Qualification

Doctor of Philosophy (PhD)

Awarding Institution

University of Cambridge