Skip to main content

LUP Student Papers

LUND UNIVERSITY LIBRARIES

Sn-Pb-mixtures for Perovskite Solar Cells

Baumann, Fanny Amanda Karolina (2020) PHYM01 20201
Solid State Physics
Department of Physics
Abstract
Perovskite research has quickly gone from non-existent to one of the biggest reseach areas in Photo- voltaics. There are still many questions to be solved regarding the stability, environmental impact, reproducible large area devices, efficiency and module fabrication cost of Perovskite Solar Cells, PSCs, before commercial up-scaling. Scientists all over the world are working towards solutions and over 15000 scientific articles were published from 2009 up until the end of 2019. Perovskite show great promise to fill the gap where Silicon Solar Cells fail today, such as inside charging for Internet Of Things and as active material in tunable bandgap tandem cells [1]. This master thesis focused on the fabrication of PSCs and the interchange... (More)
Perovskite research has quickly gone from non-existent to one of the biggest reseach areas in Photo- voltaics. There are still many questions to be solved regarding the stability, environmental impact, reproducible large area devices, efficiency and module fabrication cost of Perovskite Solar Cells, PSCs, before commercial up-scaling. Scientists all over the world are working towards solutions and over 15000 scientific articles were published from 2009 up until the end of 2019. Perovskite show great promise to fill the gap where Silicon Solar Cells fail today, such as inside charging for Internet Of Things and as active material in tunable bandgap tandem cells [1]. This master thesis focused on the fabrication of PSCs and the interchange of Lead, Pb, atoms with Tin, Sn, atoms in thin films and devices. Films with metal-organic-halide perovskite material Formamidinium(FA)LeadIodide, FAPbI3 or FAPI, and different percentage of Sn were fabricated by several methods and investigated for an extended time period. We showed that different percentage of Sn in FAPbI3 generated very different results regarding morphology, PhotoLuminescence(PL), photovoltaic performance, stablity and phase separation/segregation. The re- sults give reasonable indications that Sn compositional engineering can be used to stabilize the otherwise unstable FAPbI, probably by changing bond lenghts in the Pb-I-Pb lattice to accommodate for strain and the non-symmetrical FA cation. It is also possible that increased stability and PL performance can arise from the creation of separate phases that add in stabilizing the strain build up by creating micro- scopical 3D structures as could be seen when samples were thoroughly investigated by Scanning Electron Microscopy and Confocal Microscopy. Standard PSC in this report reached a maximum of 19.5% Power Conversion Efficiency, PCE, and pin-structure Sn-Pb-mixed PSC with 60% Sn reached over 7% PCE and a short circuit current density, Jsc, over 21 mA/cm2. Results indicated that the often used 50% Sn composition is not the most stable but that a choosing an alloy composition slightly off like 40% or 60% Sn for FAPbSnI3 can be favorable to achieve higher efficiency and longer stability. Changing ratios subsequently lead to rises and falls in the connectivity in morphology, stability, intensity of PL and X-ray Diffraction spectra depending on the composition, something that is also discussed in regard to phase separations, strain, unit cell lattice/size and morphology. (Less)
Popular Abstract (Swedish)
Högre verkningsgrader, stabilitet och minskad toxicitet;
så skall framtidens solceller nå verkligheten.

Många hoppas att solenergi ska ta över våra energibehov och varje dag närmar vi
oss en grönare utvinning av elektricitet. Kommer våra bilar och byggnader täckas av
solceller i framtiden? Inte helt omöjligt, om vi kan bemästra det fascinerande
materialet perovskit.
På EPFL, Ecóle Polytechnique Fédérale Lausanne, arbetar man dag och natt med att
optimera framtidens solceller, där står materialet Perovskit i högsta fokus. Perovskitsolceller
kan både vara tunnare och ge högre verkningsgrad per kvadratcentimeter än de solceller
som görs idag av kisel, och man tror även på att kombinera kisel och perovskit (i en så
kallad... (More)
Högre verkningsgrader, stabilitet och minskad toxicitet;
så skall framtidens solceller nå verkligheten.

Många hoppas att solenergi ska ta över våra energibehov och varje dag närmar vi
oss en grönare utvinning av elektricitet. Kommer våra bilar och byggnader täckas av
solceller i framtiden? Inte helt omöjligt, om vi kan bemästra det fascinerande
materialet perovskit.
På EPFL, Ecóle Polytechnique Fédérale Lausanne, arbetar man dag och natt med att
optimera framtidens solceller, där står materialet Perovskit i högsta fokus. Perovskitsolceller
kan både vara tunnare och ge högre verkningsgrad per kvadratcentimeter än de solceller
som görs idag av kisel, och man tror även på att kombinera kisel och perovskit (i en så
kallad tandem-cell) till en solcell med mycket hög verkningsgrad. Ett perovskitmaterial
kännetecknas av att det har en specifik kristallstruktur som följer den kemiska formeln
A-B-X3; två stycken olika stora katjoner(A och B) samt 3 stycken likadana anjoner(X).
Genom att lösa upp ett fåtal kemiska ämnen, till exempel blysalt och ammoniumjon-komplex,
tillsammans, och sedan kristallisera blandningen från flytande form under uppvärmning, kan
med lite tur en kristall som fungerar som en naturlig solcell bildas. Detta perovskitmaterial
skapar under belysning (tack vare sin unika molekylstruktur) laddningsbärare som kan ledas
in i ett selektivt lager på varsin sida av solcells-kristallen. Då får vi ut elektricitet och
spänning som vi kan använda till att uppfylla våra teknologiska behov. Gränserna mellan de
olika materialen i solcellen är mycket viktiga, men det absolut viktigaste är kvalitéen på
själva solcells-kristallen. Även om perovskit visar stora möjligheter att bidra till bättre
solceller än de som görs idag behöver forskningen övervinna flera barriärer innan vi ser
materialet i vardagen. Några av de viktigaste anledningarna till detta är materialets
icke-konsekventa kristallisering, degradering av materialet i fuktig luft, högt bandgap, stor
procentuellt innehåll bly och tillverkningskostnaden av större moduler. Vi har tittat på
möjligheter att lösa flera av dessa problem. Ett vanligt perovskitmaterial som används idag
och som påvisar problem både angående stabilitet och bly-innehåll men ger hög effektivitet
är FA-Pb-I3, eller som också kallat FAPI. FAPI är baserat på en organisk katjon, bly och
jodid. Vi har bytt ut en del bly mot tenn i materialet, något som i tidigare litteratur visat ändra
absorptionen av ljus i materialet samt bidra till att stabilisera FAPI. Intressant nog visade det
sig att olika andelar av tenn utbytt in i kristallstrukturen gav stora skillnader i
materialegenskaperna, däribland olika stabilitet, effektivitet i solceller, ljus-intagets intervall
och färg. I projektet undersöktes också flertalet andra metoder för att öka stabiliteten och
kvalitén hos solceller och på så sätt göra dem lättare för industrier att skala upp till gynnsam
produktion. Bland annat kapslades materialet in med glas efter kristallisering, det
kristalliserades med hjälp av infraröd strålning(FIRA) eller så varierades ytstrukturen under
kristallen med hjälp av mesoporösa eller kompakta(släta) elektron-selektiva material.

Referenser:
1. https://www.epfl.ch/labs/lspm/research/
2. Gustavo M. Dalpian, Xingang Zhao, Lawrence Kazmerski and Alex Zunger.
Formation and composition-dependent properties of alloys of cubic halide
perovskites. Chem. Mater. Vol 7. Pages 2497–2506. Year 2019. DOI
10.1021/acs.chemmater.8b05329
3. Chun-Sheng Jiang et al. Carrier separation and transport in perovskite solar cells
studied by nanometre-scale profiling of electrical potential. Nature Communications
Vol 6. Pages 8397. Year 2015. DOI 10.1038/ncomms9397
4. Andy Extance. Perovskites on trial, Companies say they are close to commercializing
a cheap photovoltaic material that could disrupt solar power — but are they too
optimistic?. Nature Vol 570. Pages 429-432. Year 2019.
https://www.nature.com/articles/d41586-019-01985-y
5. Ashraf Uddin et al. Encapsulation of Organic and Perovskite Solar Cells: A Review.
Coatings Vol. 9(2). Pages = 65. Year 2018. DOI 10.3390/coatings9020065
6. Wikipedia 2020-08-24. Perovskite Solar Cell.
https://en.wikipedia.org/wiki/Perovskite_solar_cell
7. Joe Berry. NREL. https://www.nrel.gov/pv/perovskite-solar-cells.html
8. Z Yang et al. Enhancing electron diffusion length in narrow-bandgap perovskites for
efficient monolithic perovskite tandem solar cells. Nature Communications Vol 10.
Article 4498. Year 2019. DOI 10.1038/s41467-019-12513-x (Less)
Please use this url to cite or link to this publication:
author
Baumann, Fanny Amanda Karolina
supervisor
organization
course
PHYM01 20201
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
Perovskite Solar Cells, PSC, Sn, Tin, Lead, Pb, FAPI, Renewable Energy, Compositional Engineering, Interfaces, Morphology, PL, Photoluminescence, Thin film stability
language
English
id
9029066
date added to LUP
2020-09-15 12:36:34
date last changed
2020-09-15 12:36:34
@misc{9029066,
  abstract     = {{Perovskite research has quickly gone from non-existent to one of the biggest reseach areas in Photo- voltaics. There are still many questions to be solved regarding the stability, environmental impact, reproducible large area devices, efficiency and module fabrication cost of Perovskite Solar Cells, PSCs, before commercial up-scaling. Scientists all over the world are working towards solutions and over 15000 scientific articles were published from 2009 up until the end of 2019. Perovskite show great promise to fill the gap where Silicon Solar Cells fail today, such as inside charging for Internet Of Things and as active material in tunable bandgap tandem cells [1]. This master thesis focused on the fabrication of PSCs and the interchange of Lead, Pb, atoms with Tin, Sn, atoms in thin films and devices. Films with metal-organic-halide perovskite material Formamidinium(FA)LeadIodide, FAPbI3 or FAPI, and different percentage of Sn were fabricated by several methods and investigated for an extended time period. We showed that different percentage of Sn in FAPbI3 generated very different results regarding morphology, PhotoLuminescence(PL), photovoltaic performance, stablity and phase separation/segregation. The re- sults give reasonable indications that Sn compositional engineering can be used to stabilize the otherwise unstable FAPbI, probably by changing bond lenghts in the Pb-I-Pb lattice to accommodate for strain and the non-symmetrical FA cation. It is also possible that increased stability and PL performance can arise from the creation of separate phases that add in stabilizing the strain build up by creating micro- scopical 3D structures as could be seen when samples were thoroughly investigated by Scanning Electron Microscopy and Confocal Microscopy. Standard PSC in this report reached a maximum of 19.5% Power Conversion Efficiency, PCE, and pin-structure Sn-Pb-mixed PSC with 60% Sn reached over 7% PCE and a short circuit current density, Jsc, over 21 mA/cm2. Results indicated that the often used 50% Sn composition is not the most stable but that a choosing an alloy composition slightly off like 40% or 60% Sn for FAPbSnI3 can be favorable to achieve higher efficiency and longer stability. Changing ratios subsequently lead to rises and falls in the connectivity in morphology, stability, intensity of PL and X-ray Diffraction spectra depending on the composition, something that is also discussed in regard to phase separations, strain, unit cell lattice/size and morphology.}},
  author       = {{Baumann, Fanny Amanda Karolina}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Sn-Pb-mixtures for Perovskite Solar Cells}},
  year         = {{2020}},
}