Dissertation committee:
Χριστίνα-Άννα Μητσοπούλου, Καθηγήτρια Τμήματος Χημείας ΕΚΠΑ
Παναγιώτης Κυρίτσης, Καθηγητής Τμήματος Χημείας ΕΚΠΑ
Κωνσταντίνος Μεθενίτης, Αναπληρωτής Καθηγητής Τμήματος Χημείας ΕΚΠΑ
Αθανάσιος Κόντος, Αναπληρωτής Καθηγητής ΣΕΜΦΕ, ΕΜΠ
Ανδρέας Καλτζόγλου, Ερευνητής Γ’ Βαθμίδας, ΙΘΦΧ , Εθνικό Ιδρυμα Ερευνών
Πολύκαρπος Φαλάρας, Ερευνητής Α’ Βαθμίδας , ΙNN, ΕΚΕΦΕ Δημόκριτος
Αθανάσιος Φιλιππόπουλος, Επίκουρος Καθηγητής Τμήματος Χημείας ΕΚΠΑ
Summary:
SUMMARY
Halide perovskite solar devices have attracted much attention in the photovoltaic com-munity, due to their efficiency in converting solar energy into electricity, which has reached values over 25.2% in the last five years. Perovskite solar cells (PSCs) evolved from the solid-state, dye-sensitized solar cells (DSSCs) by replacing the dye absorber with an ABX3 type perovskite material where A is an inorganic or/and organic cation (Cs+, (CH3NH3)+, (HC (NH2)2)+), Β is a metal cation (e.g Pb2+, Sn2+), and Χ is a halogen anion (Cl-, Br-, I-). Despite high efficiencies, this class of compounds suffers from long-term instability in ambient air due to the hygroscopic amine cations and from the toxicity of lead.
Aim of the work:
My aim is to expand the, so far, limited variety of organic cations by exploring sulfur-based analogues using trimethyl sulfonium cation ((CH3)3S)+ as stable organic moiety, that could ultimately be incorporated in solar cells for: (a) enhance power conversion efficiency , (b) increase stability against humidity, (c) decrease toxicity in lead-free perovskite.
Below, I summarized the main idea of each chapter:
Chapter (1)
Fundamental of photovoltaic solar cells devices were discussed widely. Also, the back-ground and motivation of a new technology of solar cells specially Dye-sensitized solar cells (DSSC) and Perovskites solar cells (PSCs), including fabrication processes, promises and challenges.
Chapter (2)
The materials, synthesis techniques, and characterization analysis were recorded in this chapter.
Chapter (3)
I present the synthesis, crystal structures, optoelectronic properties, and first principles theoretical ab-initio DFT calculations of a novel chemically stable (CH3)3SPbI3-xBrx and (CH3)3SPbI3-xClx (x = 0, 1, 2, 3) perovskites.
Chapter (4)
The synthesis, characterization, optoelectronic properties and multi-temperature Raman of a novel lead-free (CH3)3SSnI3 1-D perovskite were discussed.
Chapters (5,6)
A novel series of Sn4+ halide lead-free defect perovskites ((CH3)3S)2SnX6 (X = Cl, Br, I), ((CH3)3S)2SnI6-nCln and ((CH3)3S)2SnI6-nBrn (n=1, 2) were synthesized and characterized us-ing different spectroscopic techniques. Moreover, the lead-free Sn(IV)-based compounds were successfully incorporated as hole transporting materials (HTMs) in Dye-sensitized solar cells (DSCs)
Chapter (7)
Dimensionality engineering approach consisting of a (FA/MA/Cs) PbI3-xBrx/(CH3)3SPbI3 (3D/1D) perovskite bilayer architecture, fabricated exclusively with solution processes have been discussed. The 3D/1D bilayer structure further optimizes the corresponding ab-sorber/hole transporting layer (HTL) interface of the PSCs. The 1D (CH3)3SPbI3 lead to sig-nificant stability improvement for non-sealed devices both under ambient conditions and light stress
Chapter (8)
Interface engineering approach involving the utilization of the organic chromophore (E)-3-(5-(4-(bis(2',4'-dibutoxy-[1,1'-biphenyl]-4-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (D35) as an interlayer between the perovskite absorber and the hole transporter (HTM) of mesoporous PSCs. The organic D-π-A -based solar cells present supe-rior stability since they preserved 83% of their initial efficiency after 37 days of storage under dark and open circuit conditions.
Chapter (9)
I summarized the main findings, conclusions and perspective.
Chapter (10)
References
Keywords:
perovskite, solar cells, synthesis, dimensionality engineering, DFT, Dye sensitized solar cells
