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Low Dimensional Organic-Inorganic Lead Halide Perovskites: From Structure Prediction to Material Application

Lyu, Ruiyang
http://orcid.org/0000-0002-5159-2435
http://rave.ohiolink.edu/etdc/view?acc_num=osu1704307949123423

Abstract Details

2024, Doctor of Philosophy, Ohio State University, Chemistry.
Solar energy attracts increasing attention due to its abundance and high sustainability. Among all the semiconductors that can convert solar energy to electric, chemical and light energy, organic-inorganic halide perovskites (OIHPs) are being widely studied due to its promising optical and photoelectric properties as well as easy processing and fabrication. As a derivative family from 3D OIHPs, low dimensional OIHPs have their unique attributes and applications because of the strong quantum confinement, high tunability and better stability. However, compared with 3D OIHPs, low dimensional OIHPs are still less explored because of their large band gap, poor charge carrier mobility and structural prediction difficulty. In this dissertation, we first report a machine learning (ML)-assisted approach to predict the dimensionality of lead iodide-based perovskites. A literature review reveals 86 reported amines that are classified into ‘2D’-forming and ‘non-2D’-forming based on the dimensionality of their perovskites. Machining learning models were trained and tested based on the classification and descriptor features of these ammonium cations. Four structural features, including steric effect index, eccentricity, largest ring size, and hydrogen-bond donor, have been identified as the key controlling factors. Based on these features, a quantified equation is created to calculate the probability of forming 2D perovskite for a selected amine. To further illustrate its predicting capability, the built model is applied to several untested amines, and the predicted dimensionality is verified by growing single crystals of perovskites from these amines. This work represents a step towards predicting the crystal structures of low dimensional hybrid halide perovskites using ML as a tool. The poor stability of OIHPs against polar solvents highly limited their application for photocatalysis and photoelectrochemistry. Therefore, we report the use of methylviologen lead iodide (MVPb2I6) as an unprotected photoelectrode which is stable inside an acetonitrile-based polar electrolyte. Moreover, the charge-transfer absorption inside MVPb2I6 reduces its band gap to 2.1 eV and thus, makes it a suitable solar absorber. The stability of MVPb2I6 allows the use of cyclic voltammetry to determine its energetics. Stable anodic photocurrent was observed with only 28% decay after 15 hours of operation under 1 sun illumination and 0.9 V (vs NHE) applied bias towards the oxidation of I-. The degradation mechanism due to photoreduction of MVPb2I6 were also studied using SEM and a rotating ring-disk electrode (RRDE). This work illustrates the potential and challenge of using viologen-based small-band-gap 1D OIHPs to achieve stable PEC inside polar solvents without protection. With the direction from the model, we further synthesized three pairs of chiral OIHPs with good water stability constructed from chiral viologens. These OIHPs contain either 1D or 0D structures, however, still have small band gaps around 2 eV. Circular dichroism spectroscopy (CD) on transparent thin film samples of these OIHPs shows the successful transfer of the chirality from chiral viologens into the inorganic frameworks and wide CD response covering most of the visible light range. This work demonstrated the design strategy of water-stable small-band-gap chiral OIHPs through chiral viologens, and their potential application as circular photodetectors with wide detection range. In conclusion, the predictive model provides support on the material design and facilitates the discovery of new low dimensional OIHPs. The PEC and chiral optical studies based on viologen-based OIHPs demonstrate the promising potential of low dimensional OIHPs for photocatalytic and photoelectronic applications.
Yiying Wu (Advisor)
Anne Co (Committee Member)
Christopher Hadad (Committee Member)
201 p.
Chemistry
perovskite; low dimensional; organic-inorganic hybrid; machine learning; photoelectrochemistry; photoelectrode; viologen; stability; photocorrosion; chirality; circular dichroism

Recommended Citations

Citations

  • Lyu, R. (2024). Low Dimensional Organic-Inorganic Lead Halide Perovskites: From Structure Prediction to Material Application [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1704307949123423

    APA Style (7th edition)

  • Lyu, Ruiyang. Low Dimensional Organic-Inorganic Lead Halide Perovskites: From Structure Prediction to Material Application. 2024. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1704307949123423.

    MLA Style (8th edition)

  • Lyu, Ruiyang. "Low Dimensional Organic-Inorganic Lead Halide Perovskites: From Structure Prediction to Material Application." Doctoral dissertation, Ohio State University, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=osu1704307949123423

    Chicago Manual of Style (17th edition)

osu1704307949123423
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This open access ETD is published by The Ohio State University and OhioLINK.
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