Accumulation of Deep Traps at Grain Boundaries in Halide Perovskites

<div> <div> <div> <p>The behaviour of grain boundaries in polycrystalline halide perovskite solar cells remains poorly understood. Whereas theoretical studies indicate that grain boundaries are not active for electron-hole recombination, there have been observations of higher non-radiative recombination rates involving these extended defects. We find that iodine interstitial defects, which have been established as a recombination center in bulk crystals, tend to segregate at planar defects in CsPbI3. First-principles calculations show that enhanced structural relaxation of the defects at grain boundaries results in increased stability (higher concentration) and deeper trap states (faster recombination). We show how the grain boundary can be partly passivated by halide mixing or extrinsic doping, which replaces or suppresses the formation of trap states close to the grain boundaries.<br></p> </div> </div> </div>

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Characteristics of Perovskite Solar Cells with Methylammonium Iodide-Added Anti-Solvent

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19408 ◽

2021 ◽

Vol 21 (8) ◽

pp. 4367-4371

Author(s):

Sung Hwan Joo ◽

Il Tae Kim ◽

Hyung Wook Choi

Keyword(s):

Solar Cell ◽

Perovskite Solar Cells ◽

Lead Iodide ◽

Step Method ◽

Electron Hole ◽

Perovskite Layer ◽

Solar Cell Efficiency ◽

Cell Efficiency ◽

One Step ◽

Hole Recombination

The perovskite film—manufactured via a one-step method—was superficially improved through an anti-solvent process to increase solar cell efficiency. Although perovskite synthesis proceeds rapidly, a significant amount of lead iodide residue remains. Well-placed lead iodide in perovskite grains prevents electron–hole recombination; however, when irregularly placed, it interferes with the movement of electron and holes. In this study, we focused on improving the crystallinity of the perovskite layer, as well as reducing lead iodide residues by adding a methylammonium halide material to the anti-solvent. Methylammonium iodide in chlorobenzene used as an anti-solvent reduces lead iodide residues and improves the crystallinity of formamidinium lead iodide perovskite. The improved crystallinity of the perovskite layer increased the absorbance and, with reduced lead iodide residues, increased the efficiency of the perovskite solar cell by 1.914%.

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En route to a unified model for photo-electrochemical reactor optimisation. I - Photocurrent and H2 yield predictions

Journal of Materials Chemistry A ◽

10.1039/c7ta05125e ◽

2017 ◽

Vol 5 (43) ◽

pp. 22683-22696 ◽

Cited By ~ 8

Author(s):

Franky E. Bedoya-Lora ◽

Anna Hankin ◽

Geoff H. Kelsall

Keyword(s):

Electrochemical Cell ◽

Cell Model ◽

Bubble Formation ◽

Electrochemical Reactor ◽

Photon Flux ◽

Recombination Rates ◽

Electron Hole ◽

Gas Desorption ◽

H2 Yield ◽

Hole Recombination

A photo-electrochemical cell model was developed accounting for photon flux, electron–hole recombination rates, gas desorption, bubble formation and cross-over losses.

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Low-frequency lattice phonons in halide perovskites explain high defect tolerance toward electron-hole recombination

Science Advances ◽

10.1126/sciadv.aaw7453 ◽

2020 ◽

Vol 6 (7) ◽

pp. eaaw7453 ◽

Cited By ~ 14

Author(s):

Weibin Chu ◽

Qijing Zheng ◽

Oleg V. Prezhdo ◽

Jin Zhao ◽

Wissam A. Saidi

Keyword(s):

Low Cost ◽

Low Frequency ◽

Nonradiative Recombination ◽

Defect Tolerance ◽

Electron Hole ◽

Surface Hopping ◽

Recombination Processes ◽

Halide Perovskites ◽

Electron And Hole States ◽

Hole Recombination

Low-cost solution-based synthesis of metal halide perovskites (MHPs) invariably introduces defects in the system, which could form Shockley-Read-Hall (SRH) electron-hole recombination centers detrimental to solar conversion efficiency. Here, we investigate the nonradiative recombination processes due to native point defects in methylammonium lead halide (MAPbI3) perovskites using ab initio nonadiabatic molecular dynamics within surface-hopping framework. Regardless of whether the defects introduce a shallow or deep band state, we find that charge recombination in MAPbI3 is not enhanced, contrary to predictions from SRH theory. We demonstrate that this strong tolerance against defects, and hence the breakdown of SRH, arises because the photogenerated carriers are only coupled with low-frequency phonons and electron and hole states overlap weakly. Both factors appreciably decrease the nonadiabatic coupling. We argue that the soft nature of the inorganic lattice with small bulk modulus is key for defect tolerance, and hence, the findings are general to other MHPs.

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Hydroxyl radical and free and shallowly trapped electron generation and electron/hole recombination rates in TiO2 photocatalysis using different combinations of anatase and rutile

Applied Catalysis A General ◽

10.1016/j.apcata.2018.07.045 ◽

2018 ◽

Vol 565 ◽

pp. 20-25 ◽

Cited By ~ 12

Author(s):

Eva Jimenez-Relinque ◽

Marta Castellote

Keyword(s):

Hydroxyl Radical ◽

Recombination Rates ◽

Electron Hole ◽

Tio2 Photocatalysis ◽

Electron Generation ◽

Trapped Electron ◽

Hole Recombination

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Auger Recombination in Antimony-Based, Strain-Balanced, Narrow-Band-Gap Superlattics

MRS Proceedings ◽

10.1557/proc-484-83 ◽

1997 ◽

Vol 484 ◽

Cited By ~ 1

Author(s):

J. T. Olesberg ◽

Thomas F. Boggess ◽

S. A. Anson ◽

D.-J. Jan ◽

M. E. Flatté ◽

...

Keyword(s):

Auger Recombination ◽

Growth Direction ◽

Bandgap Energy ◽

Recombination Rates ◽

Electron Hole ◽

Time Resolved ◽

All Optical ◽

Semi Empirical ◽

The Impact ◽

Hole Recombination

AbstractTime-resolved all-optical techniques are used to measure the density and temperature dependence of electron-hole recombination in an InAs/GaInSb/InAs/AlGaInAsSb strain-balanced superlattice grown by molecular beam expitaxy on GaSb. This 4 μm bandgap structure, which has been designed for suppressed Auger recombination, is a candidate material for the active region of mid-infrared lasers. While carrier lifetime measurements at room temperature show unambiguous evidence of Auger recombination, the extracted Auger recombination rates are considerably lower than those reported for bulk materials of comparable bandgap energy. We find that the Auger rate saturates at carrier densities comparable to those required for degeneracy of the valence band, illustrating the impact of Fermi statistics on the Auger process. The measured results are compared with theoretical Auger rates computed using a band structure obtained from a semi-empirical 8-band K.p model. We find excellent agreement between theoretical and experimental results when Umklapp processes in the growth direction are included in the calculation. Measured recombination rates from 50 to 300 K are combined with calculated threshold carrier densities to determine a material To value for the superlattice.

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Improvement of Dye Solar Cell Efficiency by Photoanode Posttreatment

International Journal of Photoenergy ◽

10.1155/2014/835760 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Tanja Ivanovska ◽

Zoran Saponjic ◽

Marija Radoicic ◽

Luca Ortolani ◽

Vittorio Morandi ◽

...

Keyword(s):

Dye Sensitized Solar Cells ◽

Trap States ◽

Electron Recombination ◽

Electron Hole ◽

Surface Trap ◽

Solar Cell Efficiency ◽

Cell Efficiency ◽

Dye Sensitized ◽

Sensitized Solar Cells ◽

Hole Recombination

The basic concept for efficiency improvement in dye-sensitized solar cells (DSSC) is limiting the electron-hole recombination. One way to approach the problem is to improve the photogenerated charge carriers lifetime and consequently reduce their recombination probability. We are reporting on a facile posttreatment of the mesoporous photoanode by using a colloidal solution of TiO2nanoparticles. We have investigated the outcome of the different sintering temperature of the posttreated photoanodes on their morphology as well as on the conversion efficiency of the DSSC. The DSSCs composed of posttreated photoanodes at 450°C showed an increase inJSCand consequently an increase in efficiency of 10%. Investigations were made to determine the electron recombination via the electrolyte by the OCVD technique. We found that the posttreatment has the effect of reducing the surface trap states and thus increases the electron lifetime, which is responsible for the increase of the overall cell efficiency.

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Toward charge extraction in all-inorganic perovskite solar cells by interfacial engineering

Journal of Materials Chemistry A ◽

10.1039/c8ta02522c ◽

2018 ◽

Vol 6 (44) ◽

pp. 21999-22004 ◽

Cited By ~ 33

Author(s):

Jie Ding ◽

Jialong Duan ◽

Chenyang Guo ◽

Qunwei Tang

Keyword(s):

Solar Cells ◽

Perovskite Solar Cells ◽

Electron Hole ◽

Inorganic Perovskite ◽

Interfacial Engineering ◽

Charge Extraction ◽

Hole Recombination

CuInS2/ZnS QDs with tunable bandgaps were applied at the CsPbBr3/carbon interface for improved hole extraction and reduced electron–hole recombination. A PCE of as high as 8.42% was achieved for QDs tailored all-inorganic PSC in comparison with 6.01% for the pristine device.

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All-inorganic quantum dot assisted enhanced charge extraction across the interfaces of bulk organo-halide perovskites for efficient and stable pin-hole free perovskite solar cells

Chemical Science ◽

10.1039/c9sc01183h ◽

2019 ◽

Vol 10 (41) ◽

pp. 9530-9541 ◽

Cited By ~ 11

Author(s):

Dibyendu Ghosh ◽

Dhirendra K. Chaudhary ◽

Md. Yusuf Ali ◽

Kamlesh Kumar Chauhan ◽

Sayan Prodhan ◽

...

Keyword(s):

Quantum Dots ◽

Solar Cells ◽

Quantum Dot ◽

Grain Boundaries ◽

Surface Engineering ◽

Perovskite Solar Cells ◽

Inorganic Perovskite ◽

Perovskite Quantum Dots ◽

Halide Perovskites ◽

Trapping Sites

Grain boundaries in bulk perovskite films are considered as giant trapping sites for photo-generated carriers. Surface engineering via inorganic perovskite quantum dots has been employed for creating monolithically grained, pin-hole free perovskite films.

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Inverted perovskite solar cells with inserted cross-linked electron-blocking interlayers for performance enhancement

Journal of Materials Chemistry A ◽

10.1039/c5ta01479d ◽

2015 ◽

Vol 3 (17) ◽

pp. 9291-9297 ◽

Cited By ~ 28

Author(s):

Hong-Jyun Jhuo ◽

Po-Nan Yeh ◽

Sih-Hao Liao ◽

Yi-Lun Li ◽

Sunil Sharma ◽

...

Keyword(s):

Solar Cells ◽

Performance Enhancement ◽

Perovskite Solar Cells ◽

Type Solution ◽

Electron Hole ◽

Solvent Resistance ◽

Solution Processed ◽

Hole Recombination

Cross-linked anode interlayers (X-QUPD or X-OTPD) with solvent-resistance provide electron blocking to reduce electron–hole recombination for improving PCE of invert type solution processed perovskite solar cells.

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