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

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.

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The Influence of the Thickness of Compact TiO2 Electron Transport Layer on the Performance of Planar CH3NH3PbI3 Perovskite Solar Cells

Materials ◽

10.3390/ma14123295 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3295

Author(s):

Andrzej Sławek ◽

Zbigniew Starowicz ◽

Marek Lipiński

Keyword(s):

Solar Cells ◽

Electron Transport ◽

Short Circuit ◽

Photovoltaic Performance ◽

Perovskite Solar Cells ◽

Precursor Solution ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Transport Layer ◽

Electron Transport Layer

In recent years, lead halide perovskites have attracted considerable attention from the scientific community due to their exceptional properties and fast-growing enhancement for solar energy harvesting efficiency. One of the fundamental aspects of the architecture of perovskite-based solar cells (PSCs) is the electron transport layer (ETL), which also acts as a barrier for holes. In this work, the influence of compact TiO2 ETL on the performance of planar heterojunction solar cells based on CH3NH3PbI3 perovskite was investigated. ETLs were deposited on fluorine-doped tin oxide (FTO) substrates from a titanium diisopropoxide bis(acetylacetonate) precursor solution using the spin-coating method with changing precursor concentration and centrifugation speed. It was found that the thickness and continuity of ETLs, investigated between 0 and 124 nm, strongly affect the photovoltaic performance of PSCs, in particular short-circuit current density (JSC). Optical and topographic properties of the compact TiO2 layers were investigated as well.

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The Performance Improvement of Using Hole Transport Layer with Lithium and Cobalt for Inverted Planar Perovskite Solar Cell

Coatings ◽

10.3390/coatings10040354 ◽

2020 ◽

Vol 10 (4) ◽

pp. 354

Author(s):

Shaoxi Wang ◽

He Guan ◽

Yue Yin ◽

Chunfu Zhang

Keyword(s):

Solar Cells ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Hole Mobility ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Hole Transport ◽

Transport Layer ◽

Hole Transport Layer ◽

Planar Heterojunction

With the continuous development of solar cells, the perovskite solar cells (PSCs), whose hole transport layer plays a vital part in collection of photogenerated carriers, have been studied by many researchers. Interface transport layers are important for efficiency and stability enhancement. In this paper, we demonstrated that lithium (Li) and cobalt (Co) codoped in the novel inorganic hole transport layer named NiOx, which were deposited onto ITO substrates via solution methods at room temperature, can greatly enhance performance based on inverted structures of planar heterojunction PSCs. Compared to the pristine NiOx films, doping a certain amount of Li and Co can increase optical transparency, work function, electrical conductivity and hole mobility of NiOx film. Furthermore, experimental results certified that coating CH3NH3PbIxCl3−x perovskite films on Li and Co- NiOx electrode interlayer film can improve chemical stability and absorbing ability of sunlight than the pristine NiOx. Consequently, the power conversion efficiency (PCE) of PSCs has a great improvement from 14.1% to 18.7% when codoped with 10% Li and 5% Co in NiOx. Moreover, the short-circuit current density (Jsc) was increased from 20.09 mA/cm2 to 21.7 mA/cm2 and the fill factor (FF) was enhanced from 0.70 to 0.75 for the PSCs. The experiment results demonstrated that the Li and Co codoped NiOx can be a effective dopant to improve the performance of the PSCs.

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Efficient light harvesting with a nanostructured organic electron-transporting layer in perovskite solar cells

Nanoscale ◽

10.1039/c9nr03030a ◽

2019 ◽

Vol 11 (19) ◽

pp. 9281-9286 ◽

Cited By ~ 2

Author(s):

Li Wan ◽

Wenxiao Zhang ◽

Yulei Wu ◽

Xiaodong Li ◽

Changjian Song ◽

...

Keyword(s):

Solar Cells ◽

Light Harvesting ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Organic Electron ◽

Electron Transporting Layer ◽

Harvesting Efficiency ◽

Light Harvesting Efficiency

A nanostructured electron-transporting layer based on PFPDI was introduced into inverted perovskite solar cells. The light-harvesting efficiency and the short-circuit current density were greatly improved.

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RELIABILITY STUDIES OF P3HT: PCBM ORGANIC SOLAR CELLS FABRICATED WITH CALCIUM–ALUMINUM AND LITHIUM FLUORIDE–ALUMINIUM CATHODES

International Journal of Nanoscience ◽

10.1142/s0219581x11008976 ◽

2011 ◽

Vol 10 (04n05) ◽

pp. 803-807

Author(s):

T. S. KRISHNAN ◽

S. SUNDAR KUMAR IYER

Keyword(s):

Solar Cells ◽

Organic Solar Cells ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Continuous Illumination ◽

Stress Tests ◽

Ambient Conditions ◽

Over Time

This work addresses the shelf life characteristics of P3HT: PCBM blend based organic solar cells (OSC) fabricated with Ca–Al and LiF–Al cathodes. Some of these devices are encapsulated in nitrogen ambient and some in room ambient. Device electrical characteristics are studied under both dark and light. In the analysis under dark ambient conditions, the degradation in peak dark current is monitored over time (in days) and an empirical model is postulated for the degradation based on statistical curve fitting techniques. In the analysis under light, degradation of parameters such as fill factor (FF), open circuit voltage (V oc ) and short circuit current density (J sc ) is monitored over time in these devices (for different cathodes and different ambients) and the results are analyzed and compared. Also, accelerated stress tests are conducted wherein the devices are subjected to continuous illumination for a period of 1.5 h under two different intensities (0.76 sun and 1 sun) and again, the results are analyzed and compared. A model is fitted to the observed degradation in normalized J sc and the degradation constants (k deg ) are obtained. It is seen that the devices fabricated with cathode as LiF–Al and being encapsulated in nitrogen ambient provide the best performance over time.

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Iodide management in formamidinium-lead-halide–based perovskite layers for efficient solar cells

Science ◽

10.1126/science.aan2301 ◽

2017 ◽

Vol 356 (6345) ◽

pp. 1376-1379 ◽

Cited By ~ 3378

Author(s):

Woon Seok Yang ◽

Byung-Wook Park ◽

Eui Hyuk Jung ◽

Nam Joong Jeon ◽

Young Chan Kim ◽

...

Keyword(s):

Solar Cells ◽

High Performance ◽

Deep Level ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Small Cells ◽

Iodide Ions

The formation of a dense and uniform thin layer on the substrates is crucial for the fabrication of high-performance perovskite solar cells (PSCs) containing formamidinium with multiple cations and mixed halide anions. The concentration of defect states, which reduce a cell’s performance by decreasing the open-circuit voltage and short-circuit current density, needs to be as low as possible. We show that the introduction of additional iodide ions into the organic cation solution, which are used to form the perovskite layers through an intramolecular exchanging process, decreases the concentration of deep-level defects. The defect-engineered thin perovskite layers enable the fabrication of PSCs with a certified power conversion efficiency of 22.1% in small cells and 19.7% in 1-square-centimeter cells.

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Alkali Metal Cation Incorporated Ag3BiI6 Absorbers for Efficient and Stable Rudorffite Solar Cells

Oxford Open Materials Science ◽

10.1093/oxfmat/itab017 ◽

2021 ◽

Author(s):

Ming-Chung Wu ◽

Ruei-Yu Kuo ◽

Yin-Hsuan Chang ◽

Shih-Hsuan Chen ◽

Ching-Mei Ho ◽

...

Keyword(s):

Solar Cells ◽

Alkali Metal ◽

Carrier Transport ◽

Short Circuit ◽

Alkali Metal Cation ◽

Photovoltaic Performance ◽

Perovskite Solar Cells ◽

Short Circuit Current ◽

Ambient Conditions ◽

Kelvin Probe

Abstract Objectives Toxic lead and poor stability are the main obstacles of perovskite solar cells. Lead-free silver bismuth iodide (SBI) was first attempted as solar cells photovoltaic materials in 2016. However, the short-circuit current of the SBI rudorffite materials is commonly below 10 mA/cm2, limiting the overall photovoltaic performance. Here, we present a chemical composition engineering to enhance the photovoltaic performance. Methods In this study, we incorporated a series of alkali metal cations (Li+, Na+, K+, Rb+, and Cs+) into Ag3BiI6 absorbers to investigate the effects on the photovoltaic performance of rudorffite solar cells. Results Cs+ doping improved VOC and Na+ doping showed an obvious enhancement in JSC. Therefore, we co-doped Na+ and Cs+ into SBI (Na/Cs-SBI) as the absorber and investigated the crystal structure, surface morphology, and optical properties. The photo-assisted Kelvin probe force microscopy (photo-KPFM) was used to measure surface potential and verified that Na/Cs doping could reduce the electron trapping at the grain boundary and facilitate electron transportation. Conclusion Na/Cs-SBI reduced the electron-holes pairs recombination and promoted the carrier transport of rudorffite solar cells. Finally, the Na/Cs-SBI rudorffite solar cell exhibited a PCE of 2.50%, a 46.0% increase to the SBI device (PCE = 1.71%), and was stable in ambient conditions for over 6 months.

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Fabrication and Characterization of CH3NH3PbI3 Perovskite Solar Cells Added with Polysilanes

International Journal of Photoenergy ◽

10.1155/2018/8654963 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 9

Author(s):

Takeo Oku ◽

Junya Nomura ◽

Atsushi Suzuki ◽

Hiroki Tanaka ◽

Sakiko Fukunishi ◽

...

Keyword(s):

Solar Cells ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Interfacial Structure ◽

Perovskite Layer ◽

Photovoltaic Properties ◽

Coating Method

Effects of polysilane additions on CH3NH3PbI3 perovskite solar cells were investigated. Photovoltaic cells were fabricated by a spin-coating method using perovskite precursor solutions with polymethyl phenylsilane, polyphenylsilane, or decaphenyl cyclopentasilane (DPPS), and the microstructures were examined by X-ray diffraction and optical microscopy. Open-circuit voltages were increased by introducing these polysilanes, and short-circuit current density was increased by the DPPS addition, which resulted in the improvement of the photoconversion efficiencies to 10.46%. The incident photon-to-current conversion efficiencies were also increased in the range of 400~750 nm. Microstructure analysis indicated the formation of a dense interfacial structure by grain growth and increase of surface coverage of the perovskite layer with DPPS, and the formation of PbI2 was suppressed, leading to the improvement of photovoltaic properties.

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Performance Enhancement of All-Inorganic Carbon-Based CsPbIBr2 Perovskite Solar Cells Using a Moth-Eye Anti-Reflector

Nanomaterials ◽

10.3390/nano11102726 ◽

2021 ◽

Vol 11 (10) ◽

pp. 2726

Author(s):

Wensheng Lan ◽

Dazheng Chen ◽

Qirui Guo ◽

Baichuan Tian ◽

Xiaoping Xie ◽

...

Keyword(s):

Solar Cells ◽

Inorganic Carbon ◽

Performance Enhancement ◽

Low Cost ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Wide Range ◽

Carbon Based

All-inorganic carbon-based CsPbIBr2 perovskite solar cells (PSCs) have attracted increasing interest due to the low cost and the balance between bandgap and stability. However, the relatively narrow light absorption range (300 to 600 nm) limited the further improvement of short-circuit current density (JSC) and power conversion efficiency (PCE) of PSCs. Considering the inevitable reflectance loss (~10%) at air/glass interface, we prepared the moth-eye anti-reflector by ultraviolet nanoimprint technology and achieved an average reflectance as low as 5.15%. By attaching the anti-reflector on the glass side of PSCs, the JSC was promoted by 9.4% from 10.89 mA/cm2 to 11.91 mA/cm2, which is the highest among PSCs with a structure of glass/FTO/c-TiO2/CsPbIBr2/Carbon, and the PCE was enhanced by 9.9% from 9.17% to 10.08%. The results demonstrated that the larger JSC induced by the optical reflectance modulation of moth-eye anti-reflector was responsible for the improved PCE. Simultaneously, this moth-eye anti-reflector can withstand a high temperature up to 200 °C, and perform efficiently at a wide range of incident angles from 40° to 90° and under various light intensities. This work is helpful to further improve the performance of CsPbIBr2 PSCs by optical modulation and boost the possible application of wide-range-wavelength anti-reflector in single and multi-junction solar cells.

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The N, N-Dimethylformamide Annealing for Enhanced Performance of Perovskite Solar Cells Fabricated in Ambient Air

NANO ◽

10.1142/s1793292018501023 ◽

2018 ◽

Vol 13 (09) ◽

pp. 1850102

Author(s):

Xiude Yang ◽

Debei Liu ◽

Ping Li ◽

Bo Wu ◽

Haishen Huang ◽

...

Keyword(s):

Solar Cells ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Solution Process ◽

Cost Effective ◽

Short Circuit Current ◽

Ambient Air ◽

Short Circuit Current Density ◽

Coating Method ◽

One Step

By adopting N, N-Dimethylformamide (DMF) atmosphere annealing at room temperature, planar perovskite solar cells with a p-i-n structure of ITO/PEDOT:PSS/Perovskite/PCBM/C[Formula: see text]/Al are fabricated by a simple one-step solution process in ambient air with humidity around 50%, and the influence of DMF atmosphere on perovskite solar cells (PSCs) is systematically investigated. Compared to the reference device without DMF reaction, the perovskite films treated by modest DMF annealing show a better distribution and a higher densification, and thus the power conversion efficiency (PCE), short circuit current density ([Formula: see text] and fill factor (FF) are increased by about 17%, 8% and 6%, respectively. This work displays the importance of solvent annealing for perovskite film prepared by the one-step spin-coating method, and possibly provides a simple and cost-effective way to efficiently fabricate PSCs in ambient air.

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Cesium Doping for Performance Improvement of Lead(II)-acetate-Based Perovskite Solar Cells

Materials ◽

10.3390/ma14020363 ◽

2021 ◽

Vol 14 (2) ◽

pp. 363

Author(s):

Min-Seok Han ◽

Zhihai Liu ◽

Xuewen Liu ◽

Jinho Yoon ◽

Eun-Cheol Lee

Keyword(s):

Solar Cells ◽

Performance Improvement ◽

Fill Factor ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Perovskite Materials ◽

Lead Source

Lead(II)-acetate (Pb(Ac)2) is a promising lead source for the preparation of organolead trihalide perovskite materials, which avoids the use of inconvenient anti-solvent treatment. In this study, we investigated the effect of cesium doping on the performance of Pb(Ac)2-based perovskite solar cells (PSCs). We demonstrate that the quality of the CH3NH3PbI3 perovskite film was improved with increased crystallinity and reduced pinholes by doping the perovskite with 5 mol% cesium. As a result, the power conversion efficiency (PCE) of the PSCs was improved from 14.1% to 15.57% (on average), which was mainly induced by the significant enhancements in short-circuit current density and fill factor. A PCE of 18.02% was achieved for the champion device of cesium-doped Pb(Ac)2-based PSCs with negligible hysteresis and a stable output. Our results indicate that cesium doping is an effective approach for improving the performance of Pb(Ac)2-based PSCs.

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