Since their first introduction in the research arena, the hybrid organic-inorganic perovskite photovoltaic cells have been showing frequent record breaking power conversion efficiencies (PCEs). Despite the rapid increase in PCE by engaging new perovskite materials as active layers as well as new fabrication techniques, their stability remains too poor to go for a mass production. Mainly the organic materials in the hybrid PSCs are responsible for this instability. Consequently, very recently, different approaches are taken to replace these organic components by inorganic ones to fabricate all-inorganic PSCs. Though these first-generation all-inorganic PSCs are yet to produce competitive PCEs like their counterparts, they have already demonstrated superb stability to be a propitious bidder for solar cell energy yielding. The state-of-the-art quantum dots based cells shown efficiency as high as 10.77% and intact stability for months.
Forming section troubleshooting checklist for improving wire life (1).ppt
Progress in all inorganic perovskite solar cell
1. Progress in All Inorganic Perovskite Thin
Film for Solar Cell Application
Md Ataul Mamun
MS Student
Dept. of EE&CS
South Dakota State University (SDSU)
Instructor: Dr. Ashish Dubey
1
3. Introduction
• Energy plays a significant role for the evolution of human society and its
impact on life is massive.
• Being a non-renewable source of energy, fossil fuel is going to be finished
in near future as the rate of energy consumption increases day by day,
which leads scientists to think of an alternative and endless source of
energy.
• As a source of renewable energy, the prospect of solar cells is enormous not
only because it is inexhaustible but also it is pollution free, and available
almost everywhere on the earth.
• The energy radiated by sun on earth is about 3x1034J per hour which is
more than the current consumption of earth at present[1].
• However, to utilize this huge energy, the search for appropriate elements
for an efficient, stable, and economical photovoltaic cell is still going on.
3
1. Gratzel, M., Photoelectrochemical cells. Nature, 2001. 414(6861): p. 338-344.
4. Introduction
• Power conversion efficiencies (PCEs) for hybrid PSCs have exhibited
meteoric rise from 3.8% in 2009 to 22.1% in early 2016[2].
• The reason why they are good for photovoltaic cells is because they exhibit
suitable bandgaps (between 1.5 and 2.3 eV), high mobility, good
electron/hole diffusion length and low exciton binding energies [3].
• Despite all these qualities their stability remains too poor to go for a mass
production.
• Mainly the organic materials are responsible for this instability.
• Eg., CH3NH3PbI3 dissociates into PbI2 and CH3NH3I
• Consequently, very recently, different approaches are taken to replace
these organic components by inorganic ones to fabricate all-inorganic PSCs
4
2. Correa-Baena, J.-P., et al., The rapid evolution of highly efficient perovskite solar cells. Energy & Environmental
Science, 2017. 10(3): p. 710-727.
3. D’Innocenzo, V., et al., Excitons versus free charges in organo-lead tri-halide perovskites. Nature communications,
2014. 5.
5. • Si based cells are currently dominating in the markets, but their per watt cost is still high
enough in comparison to fossil fuel.
• All out search to replace Si cells with other organic/inorganic low cost photovoltaic cells such
as CdTe, CZTS, polymer, dye sensitized, and perovskite based cells are among them.
• But none of them demonstrated all out performance, and each cell shows its own limitations
to go for mass production.
5
Background
Type Pros Cons
CdTe High efficiency (21%) Both Cd, Te are toxic
CZTS Suitable band gap
1.45-1.6 eV
Low efficiency (around 12%),
difficult to synthesis
Polymer Low production cost Low efficiency (Less than 12%)
DSSC Low production cost Low efficiency (Less than 13%)
Hybrid
perovskite
High efficiency (~24%) Very unstable
6. Theory
6
• Photon absorption in perovskite layer
• Photo generated electrons move to electron transport layer
• Photo generated holes move to hole transport layer
• Charge collection at electrodes
TiO2
CH3NH3PbI3
Polymer
(PDPP3T)
Ag
FTO
-4.1
-7.3
-3.93
-5.43
-3.74
-5.3
-4.7
-4.4
h+
e-
e-
h+
7. Objective
• To study the current progress and identify challenges of all-inorganic PSC
and their future prospect
Motivation
• All-inorganic PSCs are expected to provide high stability as well as efficiency
to manufacture them commercially
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8. Different Fabrication Approaches
• CsPbI3-based all-inorganic PSC
• CsPbBr3-based all-inorganic PSC
• CsPbI3 quantum-dot based all-inorganic PSC
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9. CsPbI3-based all-inorganic PSC
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• Geles at el. reported first ever all-inorganic PSC [4]
• CsPbI3 serves as the active layer in solar cells thus its processing is
crucial.
• At room temperature it exhibits a yellow orthorhombic phase with wide
bandgap (around 2.82 eV) which is not suitable for photovoltaic cell
applications.
• To make the bandgap suitable (near 1.73eV) it should be heated up to
310C to form black cubic phase
• If this black phase as a thin film is not exposed to air, even at the room
temperature, it remains stable for weeks[4].
• However, the conversion of yellow to black phase can also be possible at
only 100C by annealing it for 10 minutes with presence of hydrogen
iodide (HI)[4]. The later method is more convenient and in fact shows
better result.
4. Eperon, G.E., et al., Inorganic caesium lead iodide perovskite solar cells. Journal of Materials Chemistry A, 2015. 3(39):
p. 19688-19695.
10. CsPbI3-based all-inorganic PSC
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Figure: Different phases of CsPbI3 (a) transition from orthorhombic yellow to cubic
black phase (b) Absorbance spectra of black and yellow phases of CsPbI3 (c) XRD of
black phase thin films with peaks assigned to a cubic lattice (Peaks marked with * are
those assigned to the FTO substrate).
Blackphase1.73eV
yellowphase 2.82eV
11. CsPbI3-based all-inorganic PSC
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Figure: (a) Comparison of low temp (with HI) and high temperature absorbance spectra Inset:
magnification of onset (b) SEM of films fabricated without and with HI additive at high and low
temperature respectively
Low temp. (110C) synthesis with HI gives better morphology
12. CsPbI3-based all-inorganic PSC
12
Figure: Architecture and properties of solar cells. (a) Planner regular, mesoporous, and planner inverted
solar cells based on CsPbI3 (b) Corresponding J-V characteristics measured under simulated AM1.5G
illumination, scanning from forward to reverse bias at 0.1 Vs-1
13. Achievements:
• 1st ever reported all-inorganic PSC
• Low temperature synthesis of CsPbI3
Challenges:
• Very low efficiency
• High hysteresis
13
CsPbI3-based all-inorganic PSC
Figure: J-V characteristics measured at
different sweep rates for regular planar
devices
Type Jsc Voc PCE
Planar regular 12 mA/cm2 0.8 V 2.9%
Mesoporous 10 mA/cm2 0.6V 1.3%
Planar inverted
3.7 mA/cm2 0.84 1.7%
14. Features:
• Reported by Jia Liang et al. [5]
• Unlike the hybrid organic-inorganic PSCs, this cell fabrication can be
completed in ambient environment without humidity control.
• Can endure in temperature from -22C to 100C.
• Stable cubic phase of CsPbBr3 in ambient conditions
• The band gap is little high around 2.3eV.
• C is used as a bifunctional film for effective HTM (hole transport material)
as well as a collector.
14
CsPbBr3-based all-inorganic PSC
5. Liang, J., et al., All-Inorganic Perovskite Solar Cells. Journal of the American Chemical Society, 2016.
138(49): p. 15829-15832.
15. CsPbBr3-based all-inorganic PSC
15
Figure: (a) Cross-sectional view of CsPbBr3/carbon-based all-inorganic PSCs (b) Energy level
diagram of the cell depicting smooth electron and hole collection (c) Crystal structure of cubic phase
CsPbBr3 (d) XRD pattern generated by CsPbBr3, FTO, and TiO2 without C layer. (e) Absorption
spectrum of CsPbBr3 shows bandgap of around 2.3eV [5]
16. 16
Figure: (a) Cross-sectional SEM image of the photovoltaic cell (b) SEM image of the
inorganic perovskite CsPbBr3 layer (c) SEM image of the carbon electrode that served as both
the HTM and the counter electrode, showing carbon nanoparticles with average diameter of
∼80 nm.[5]
CsPbBr3-based all-inorganic PSC
CsPbBr3 Carbon
nanoparticles
17. CsPbBr3-based all-inorganic PSC
17
Figure: (a) J−V diagram of CsPbBr3 based all-inorganic PSCs. (b) PCE histogram for 40 individual
CsPbBr3-based fabricated cells (c) Comparison of normalized PCEs at 25C without encapsulation
(d) Comparison of normalized PCEs at 100 °C without encapsulation. [5]
18. CsPbBr3-based all-inorganic PSC
18
Achievements:
• Better efficiency than
CsPbI3 based cell
• Stable in harsh conditions
even after 80 day
Challenges:
• Low efficiency
• Hysteresis
Figure: J-V curve for 1.0cm2 cell showing
hysteresis in the forward and reverse
scanning modes.
19. Features:
• Reported by Swarnkar et al. [6]
• Suitable bang gap as CsPbI3 is used instead of CsPbBr3
• Stable for even two months.
• Highest efficiency (10.77%) among all the other all-inorganic PSCs
• Bandgap is easily tunable
• High open circuit voltage (1.24V)
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6. Swarnkar, A., et al., Quantum dot–induced phase stabilization of α-CsPbI3 perovskite for high-efficiency photovoltaics.
Science, 2016. 354(6308): p. 92-95.
CsPbI3 quantum-dot based all-inorganic PSC
20. 20
CsPbI3 quantum-dot based all-inorganic PSC
Figure: Characterization of CsPbI3 nano-particles (a) Normalized UV-vis absorption spectra and photographs of
CsPbI3 QDs synthesized at different temperature (b) XRD patterns of QDs synthesized at different temperatures
confirm that they crystallize in the cubic phase of CsPbI3.[6]
21. 21
CsPbI3 quantum-dot based all-inorganic PSC
Figure: (a) Powder XRD patterns of CsPbI3 quantum dots and (b) UV-visible
absorption spectra normalized at 370 nm of CsPbI3 QDs, Inset: Amplification
of the onset [6]
22. 22
CsPbI3 quantum-dot based all-inorganic PSC
Figure: Architecture and characteristics of CsPbI3 QD-based photovoltaic devices (a)
Schematic of the cells with quantum dots (b) SEM image of the cross-section of the cell
(C) J-V curves of a device measured in air over the course of 15 days[6]
23. Achievements:
• Highest efficiency among reported all all-inorganic PSCs
• Very high stability (Intact even after two months)
Challenges:
• Moderate efficiency compared to hybrid PSC
• Hysteresis amount not shown
23
CsPbI3 quantum-dot based all-inorganic PSC
24. Conclusion
• Though comparatively new in research field, all-inorganic PSCs have
demonstrated superb stability with moderate efficiency and can be a
potential candidate to replace Si bases cells.
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Acknowledgements
Dr. Ashish Dubey
Dept. of EE &CS, SDSU