Perovskite Quantum Dot Photovoltaic Materials beyond the Reach of Thin Films: Full-Range Tuning of A-Site Cation Composition

Hazarika, Abhijit; Zhao, Qian; Gaulding, E. Ashley; Christians, Jeffrey A.; Dou, Benjia; Marshall, Ashley R.; Moot, Taylor; Berry, Joseph J.; Johnson, Justin C.; Luther, Joseph M.

doi:10.1021/acsnano.8b05555

Cited by 215 publications

(299 citation statements)

References 90 publications

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“…Perovskite NCs display many of the same exciting features as thin films with the added benefit of being fully crystallized in the perovskite structure while still in solution, having brighter emission (in many cases demonstrated with close to 100% photoluminescence (PL) quantum yield), and having large and well‐controlled surface‐to‐volume ratios . We seek to exploit this large surface‐to‐volume ratio to enable the uniform distribution of molecular dopants, and the concomitant fine control over majority carrier density, throughout well‐coupled arrays of perovskite NCs.…”

Section: Fp‐trmc Yield‐mobility Products (φσμ) For the Samples Displamentioning

confidence: 99%

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI₃ Nanocrystal Films

et al. 2019

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Doping of semiconductors enables fine control over the excess charge carriers, and thus the overall electronic properties, crucial to many technologies. Controlled doping in lead-halide perovskite semiconductors has thus far proven to be difficult. However, lower dimensional perovskites such as nanocrystals, with their high surface-area-to-volume ratio, are particularly well-suited for doping via ground-state molecular charge transfer. Here, the tunability of the electronic properties of perovskite nanocrystal arrays is detailed using physically adsorbed molecular dopants. Incorporation of the dopant molecules into electronically coupled CsPbI 3 nanocrystal arrays is confirmed via infrared and photoelectron spectroscopies. Untreated CsPbI 3 nanocrystal films are found to be slightly p-type with increasing conductivity achieved by incorporating the electron-accepting dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F 4 TCNQ) and decreasing conductivity for the electron-donating dopant benzyl viologen. Time-resolved spectroscopic measurements reveal the time scales of Auger-mediated recombination in the presence of excess electrons or holes. Microwave conductance and field-effect transistor measurements demonstrate that both the local and long-range hole mobility are improved by F 4 TCNQ doping of the nanocrystal arrays. The improved hole mobility in photoexcited p-type arrays leads to a pronounced enhancement in phototransistors.

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Section: Fp‐trmc Yield‐mobility Products (φσμ) For the Samples Displamentioning

confidence: 99%

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI₃ Nanocrystal Films

et al. 2019

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“…Several efforts have built the devices with quite inspiring efficiency using the CsPbI 3 QD film as the active layer . However, the CsPbI 3 QDs are usually deposited to form the thin film by the spin‐coating method.…”

Section: Introductionmentioning

confidence: 99%

Spray‐Coated Colloidal Perovskite Quantum Dot Films for Highly Efficient Solar Cells

Yuan

Wang

et al. 2019

Adv Funct Materials

118

137

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A fully automated spray-coated technology with ultrathin-film purification is exploited for the commercial large-scale solution-based processing of colloidal inorganic perovskite CsPbI 3 quantum dot (QD) films toward solar cells. This process is in the air outside the glove box. To further improve the performance of QD solar cells, the short-chain ligand of phenyltrimethylammonium bromide (PTABr) with a benzene group is introduced to partially substitute for the original long-chain ligands of the colloidal QD surface (namely PTABr-CsPbI 3 ). This process not only enhances the carrier charge mobility within the QD film due to shortening length between adjacent QDs, but also passivates the halide vacancy defects of QD by Br − from PTABr. The colloidal QD solar cells show a power conversion efficiency (PCE) of 11.2% with an open voltage of 1.11 V, a short current density of 14.4 mA cm −2 , and a fill factor of 0.70. Due to the hydrophobic surface chemistry of the PTABr-CsPbI 3 film, the solar cell can maintain 80% of the initial PCE in ambient conditions for one month without any encapsulation. Such a low-cost and efficient spraycoating technology also offers an avenue to the film fabrication of colloidal nanocrystals for electronic devices.with a large bandgap of 2.82 eV. [24,25] Many efforts have tried to partly replace I − with Br − to increase the stability of the black phase. [17,26,27] Unfortunately, the introduction of the bromine component enlarges the bandgap of the perovskite, correspondingly to harm the light-harvesting performance. The cubic structure of CsPbI 3 also can be stabilized by the colloidal quantum dot (QD) method, because the enlarging surface energy inhibits the phase transition. [28][29][30] In addition, on the basis of the multiple exciton generation effects, the narrow bandgap colloidal QDs will exceed the single-junction Shockley-Queisser solar efficiency limit to achieve higher theoretical efficiency. [31,32] Several efforts have built the devices with quite inspiring efficiency using the CsPbI 3 QD film as the active layer. [14,30,[33][34][35][36][37][38] However, the CsPbI 3 QDs are usually deposited to form the thin film by the spin-coating method. This method is an undesirable way to realize the scaled manufacture of the QD thin film because of the small deposition area. [39] To economize the cost of materials and realize scalable film deposition, the spray coating is emerging as a typical process for the fabrication of the thin films and has been used in the commercial paint coat technology. [32,39] However, the spray-coating process is hard to obtain high quality compact thin-film of colloidal QD due to long chain surface organic ligands of QD that weakens the adhesive force between QD and substrate. The surface ligands are obstructive to the formation of QD films and performance of the devices by hindering the charge transport. But the surface ligands are necessary to maintain monodisperse QDs and suppress their agglomeration. How to balance the surface ligands and the adhesive f...

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“…Although PbX 2 –DMSO complexes have been known for decades, it is unclear how CsI will interact with the solvents, and hence might impact crystallization at higher concentrations. For the most commonly used wide‐bandgap perovskites, FA x Cs 1− x Pb(I y Br 1− y ) 3 , typically up to 30% Cs is utilized, although up to 50% Cs has been reported . In applications where higher temperature operation may be experienced or perhaps when organic outgassing is a concern, such as operation in space, all‐inorganic perovskites may prove to be the most useful.…”

Section: Introductionmentioning

confidence: 99%

CsI‐Antisolvent Adduct Formation in All‐Inorganic Metal Halide Perovskites

Moot

Marshall

Wheeler

et al. 2020

Advanced Energy Materials

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The excellent optoelectronic properties demonstrated by hybrid organic/inorganic metal halide perovskites are all predicated on precisely controlling the exact nucleation and crystallization dynamics that occur during film formation. In general, high‐performance thin films are obtained by a method commonly called solvent engineering (or antisolvent quench) processing. The solvent engineering method removes excess solvent, but importantly leaves behind solvent that forms chemical adducts with the lead‐halide precursor salts. These adduct‐based precursor phases control nucleation and the growth of the polycrystalline domains. There has not yet been a comprehensive study comparing the various antisolvents used in different perovskite compositions containing cesium. In addition, there have been no reports of solvent engineering for high efficiency in all‐inorganic perovskites such as CsPbI3. In this work, inorganic perovskite composition CsPbI3 is specifically targeted and unique adducts formed between CsI and precursor solvents and antisolvents are found that have not been observed for other A‐site cation salts. These CsI adducts control nucleation more so than the PbI2–dimethyl sulfoxide (DMSO) adduct and demonstrate how the A‐site plays a significant role in crystallization. The use of methyl acetate (MeOAc) in this solvent engineering approach dictates crystallization through the formation of a CsI–MeOAc adduct and results in solar cells with a power conversion efficiency of 14.4%.

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Perovskite Quantum Dot Photovoltaic Materials beyond the Reach of Thin Films: Full-Range Tuning of A-Site Cation Composition

Cited by 215 publications

References 90 publications

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI₃ Nanocrystal Films

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI₃ Nanocrystal Films

Spray‐Coated Colloidal Perovskite Quantum Dot Films for Highly Efficient Solar Cells

CsI‐Antisolvent Adduct Formation in All‐Inorganic Metal Halide Perovskites

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Perovskite Quantum Dot Photovoltaic Materials beyond the Reach of Thin Films: Full-Range Tuning of A-Site Cation Composition

Cited by 215 publications

References 90 publications

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI3 Nanocrystal Films

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI3 Nanocrystal Films

Spray‐Coated Colloidal Perovskite Quantum Dot Films for Highly Efficient Solar Cells

CsI‐Antisolvent Adduct Formation in All‐Inorganic Metal Halide Perovskites

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Product

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Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI₃ Nanocrystal Films

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI₃ Nanocrystal Films