scholarly journals An antibonding valence band maximum enables defect-tolerant and stable GeSe photovoltaics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shun-Chang Liu ◽  
Chen-Min Dai ◽  
Yimeng Min ◽  
Yi Hou ◽  
Andrew H. Proppe ◽  
...  
Keyword(s):  
Solar Cells ◽  
Valence Band ◽  
Surface Passivation ◽  
Defect Density ◽  
Perovskite Solar Cells ◽  
Valence Band Maximum ◽  
Ambient Conditions ◽  
Band Maximum ◽  
Point Tracking ◽  
Power Point

AbstractIn lead–halide perovskites, antibonding states at the valence band maximum (VBM)—the result of Pb 6s-I 5p coupling—enable defect-tolerant properties; however, questions surrounding stability, and a reliance on lead, remain challenges for perovskite solar cells. Here, we report that binary GeSe has a perovskite-like antibonding VBM arising from Ge 4s-Se 4p coupling; and that it exhibits similarly shallow bulk defects combined with high stability. We find that the deep defect density in bulk GeSe is ~1012 cm−3. We devise therefore a surface passivation strategy, and find that the resulting GeSe solar cells achieve a certified power conversion efficiency of 5.2%, 3.7 times higher than the best previously-reported GeSe photovoltaics. Unencapsulated devices show no efficiency loss after 12 months of storage in ambient conditions; 1100 hours under maximum power point tracking; a total ultraviolet irradiation dosage of 15 kWh m−2; and 60 thermal cycles from −40 to 85 °C.

scholarly journals Chemical anti-corrosion strategy for stable inverted perovskite solar cells

2020 ◽  
Vol 6 (51) ◽  
pp. eabd1580
Author(s):  
Xiaodong Li ◽  
Sheng Fu ◽  
Wenxiao Zhang ◽  
Shanzhe Ke ◽  
Weijie Song ◽  
...  
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Electrochemical Corrosion ◽  
Metal Electrodes ◽  
Maximum Power Point ◽  
Perovskite Layer ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Organic Corrosion Inhibitor ◽  
Power Point

One big challenge for long-lived inverted perovskite solar cells (PSCs) is that commonly used metal electrodes react with perovskite layer, inducing electrode corrosion and device degradation. Motivated by the idea of metal anticorrosion, here, we propose a chemical anticorrosion strategy to fabricate stable inverted PSCs through introducing a typical organic corrosion inhibitor of benzotriazole (BTA) before Cu electrode deposition. BTA molecules chemically coordinate to the Cu electrode and form an insoluble and polymeric film of [BTA-Cu], suppressing the electrochemical corrosion and reaction between perovskite and the Cu electrode. PSCs with BTA/Cu show excellent air stability, retaining 92.8 ± 1.9% of initial efficiency after aging for 2500 hours. In addition, >90% of initial efficiency is retained after 85°C aging for over 1000 hours. PSCs with BTA/Cu also exhibit good operational stability, and 88.6 ± 2.6% of initial efficiency is retained after continuous maximum power point tracking for 1000 hours.

scholarly journals Pulsatile therapy for perovskite solar cells

2021 ◽  
Author(s):  
Mansoo Choi ◽  
Kiwan Jeong ◽  
Junseop Byeon ◽  
Jihun Jang ◽  
Namyoung Ahn
Keyword(s):  
Solar Cells ◽  
Reverse Bias ◽  
Defect Formation ◽  
Perovskite Solar Cells ◽  
Steady Increase ◽  
Point Tracking ◽  
Hybrid Perovskite ◽  
Pl Intensity ◽  
Power Point

Abstract Although photovoltaics employing hybrid perovskite halides have continuously been breaking world- records of power conversion efficiency (PCE) and expectations for their industrialization are rapidly rising, long-term stability issue that has greatly hampered the commercialization of perovskite solar cells has not been resolved yet. Ion instability and trapped charges were suggested as a fundamental reason for perovskite device degradation. Here, we report a pulsatile therapy relieving the accumulation of both trapped charges and ions in the perovskite solar cell device during the middle of maximum power point tracking (MPPT) for reviving the device and prolonging its device lifetime. In the technique, reverse biases are repeatedly applied for a very short time to eliminate the charges accumulated and re-distribute the ions migrated during power harvesting without any pause of operation. Intriguingly, the therapy is not only delaying irreversible degradation, but also, restoring the degraded power right after a short reverse bias. In-situ photoluminescence (PL) and photocurrent (PC) measurements for the working device were done while applying the pulsatile therapy for studying the underlying physics. Time evolving PL intensity and PC not only revealed the steady increase of PL intensity during the therapy indicating the reduction of non-radiative recombination, but also strikingly showed the restoration of degraded PL intensity and PC right after a short reverse bias suggesting the device healing. In the long-term test, we observed outstanding improvement of device stability and total harvesting power. A model considering trap-assisted recombination has also been developed to explain the efficacy of the therapy based on defect formation during MPPT operation and defect healing by the pulsatile therapy. The unique technique will open up new possibility to commercialize perovskite materials into a real market.

Zn(O,OH) layers in chalcopyrite thin-film solar cells: Valence-band maximum versus composition

2005 ◽  
Vol 98 (5) ◽  
pp. 053702 ◽  
Author(s):  
M. Bär ◽  
J. Reichardt ◽  
A. Grimm ◽  
I. Kötschau ◽  
I. Lauermann ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Valence Band ◽  
Valence Band Maximum ◽  
Thin Film Solar Cells ◽  
Band Maximum

Reliable Performance Comparison of Perovskite Solar Cells Using Optimized Maximum Power Point Tracking (Solar RRL 2∕2019)

Solar RRL ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 1970024
Author(s):  
Lucija Rakocevic ◽  
Felix Ernst ◽  
Nadine T. Yimga ◽  
Saumye Vashishtha ◽  
Tom Aernouts ◽  
...  
Keyword(s):  
Solar Cells ◽  
Maximum Power Point Tracking ◽  
Perovskite Solar Cells ◽  
Performance Comparison ◽  
Maximum Power ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Reliable Performance ◽  
Power Point

Reliable Performance Comparison of Perovskite Solar Cells Using Optimized Maximum Power Point Tracking

Solar RRL ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 1800287 ◽  
Author(s):  
Lucija Rakocevic ◽  
Felix Ernst ◽  
Nadine T. Yimga ◽  
Saumye Vashishtha ◽  
Tom Aernouts ◽  
...  
Keyword(s):  
Solar Cells ◽  
Maximum Power Point Tracking ◽  
Perovskite Solar Cells ◽  
Performance Comparison ◽  
Maximum Power ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Reliable Performance ◽  
Power Point

scholarly journals In situ grown bifacial graphene stabilizes composite electrode for efficient perovskite solar cells

2021 ◽  
Author(s):  
Liyuan Han ◽  
Xuesong Lin ◽  
Hongzhen Su ◽  
Sifan He ◽  
Yenan Song ◽  
...  
Keyword(s):  
Solar Cells ◽  
Composite Electrode ◽  
Perovskite Solar Cells ◽  
Chemical Vapor ◽  
Adhesive Layer ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Improved Stability ◽  
Power Point

Abstract Instability of rear electrodes undermines the long-term operational durability of efficient perovskite solar cells (PSCs). Here, a composite electrode of copper-nickel (Cu-Ni) alloy stabilized by in situ grown bifacial graphene is designed. The alloying makes the work function of Cu suitable for regular PSCs and Cu-Ni is the ideal substrate for preparing high-quality graphene via chemical vapor deposition, which simultaneously protects the device from oxygen, water and internal components reaction. To rivet the composite electrode with semi-device, a thermoplastic copolymer is employed as an adhesive layer during hot pressing. The resultant device achieved power conversion efficiency of 24.34% with significantly improved stability; the devices without encapsulation retained 97% of their initial efficiency after the damp heat test at 85oC with relative humidity of 85% for 1440 hours and the encapsulated devices maintained 95% of their initial efficiencies after maximum power point tracking under continuous 1 sun illumination for 5000 hours.

Efficient, stable solar cells by using inherent bandgap of α-phase formamidinium lead iodide

Science ◽  
2019 ◽  
Vol 366 (6466) ◽  
pp. 749-753 ◽  
Author(s):  
Hanul Min ◽  
Maengsuk Kim ◽  
Seung-Un Lee ◽  
Hyeonwoo Kim ◽  
Gwisu Kim ◽  
...  
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Perovskite Solar Cells ◽  
Short Circuit Current ◽  
Control Device ◽  
Short Circuit Current Density ◽  
Ambient Conditions ◽  
Lead Iodide ◽  
Point Tracking ◽  
Α Phase

In general, mixed cations and anions containing formamidinium (FA), methylammonium (MA), caesium, iodine, and bromine ions are used to stabilize the black α-phase of the FA-based lead triiodide (FAPbI3) in perovskite solar cells. However, additives such as MA, caesium, and bromine widen its bandgap and reduce the thermal stability. We stabilized the α-FAPbI3 phase by doping with methylenediammonium dichloride (MDACl2) and achieved a certified short-circuit current density of between 26.1 and 26.7 milliamperes per square centimeter. With certified power conversion efficiencies (PCEs) of 23.7%, more than 90% of the initial efficiency was maintained after 600 hours of operation with maximum power point tracking under full sunlight illumination in ambient conditions including ultraviolet light. Unencapsulated devices retained more than 90% of their initial PCE even after annealing for 20 hours at 150°C in air and exhibited superior thermal and humidity stability over a control device in which FAPbI3 was stabilized by MAPbBr3.

scholarly journals Tetrabutylammonium cations for moisture-resistant and semitransparent perovskite solar cells

2017 ◽  
Vol 5 (42) ◽  
pp. 22325-22333 ◽  
Author(s):  
Isabella Poli ◽  
Salvador Eslava ◽  
Petra Cameron
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Ambient Conditions ◽  
The Stability ◽  
Moisture Resistant

Tetra-butylammonium cations have been partially substituted for methylammonium cations in perovskite thin films. The stability of devices stored under ambient conditions was enhanced by the presence of TBA and cells with high mol% TBA were found to have reasonable efficiencies while being semi-transparent.

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