Operation Mechanism of Perovskite Quantum Dot Solar Cells Probed by Impedance Spectroscopy

Zolfaghari, Zahra; Hassanabadi, Ehsan; Pitarch-Tena, Didac; Yoon, Seog Joon; Shariatinia‬, Zahra; Lagemaat, Jao van de; Luther, Joseph M.; Mora‐Seró, Iván

doi:10.1021/acsenergylett.8b02157

Cited by 79 publications

(59 citation statements)

References 61 publications

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“…Interestingly, the data shows  =  (see Table 1) where  is obtained from the slope of the LF resistance, as also reported in the literature. 36,38,39 In addition, the CLf becomes flat at the same Vd (Vd = Vappl-Vseries) at which the resistance reaches its saturation value. These facts point towards a coupled LF resistance and capacitance, with a corresponding characteristic time, LF = RLFCLF, roughly voltage independent ( Figure S7).…”

Section: Resultsmentioning

confidence: 99%

Impedance analysis of perovskite solar cells: a case study

et al. 2019

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Section: Resultsmentioning

confidence: 99%

Impedance analysis of perovskite solar cells: a case study

et al. 2019

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“…In fact, recombination decreased by increasing the layer thickness, as confirmed by electrochemical impedance spectroscopy (EIS) analysis. 147 However, a too thick TiO 2 layer caused high series resistance.…”

Section: High-temperature Processed Front Electrodesmentioning

confidence: 99%

Carbon-based materials for stable, cheaper and large-scale processable perovskite solar cells

Fagiolari

Bella

2019

Energy Environ. Sci.

258

188

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Almost ten years after their first use in the photovoltaic (PV) field, perovskite solar cells (PSCs) are now hybrid devices that, in addition to having reached silicon performance, can accelerate the energy transition and boost the use of abundant elements for their manufacturing process. However, noble metals (in particular gold) represent the most typically used sources for back electrode fabrication, and this issue has been intensively considered by the research community in the last five years. This review shows how the most promising solution, considering also the need to develop a large-scale production process, is based on the use of carbon-based materials for the preparation of back electrodes. Graphite, carbon black, graphene and carbon nanotubes (CNTs) have been proposed, functionalized and characterized, leading to laboratory-scale solar cells and modules capable of providing excellent efficiencies and ensuring stability greater than those of gold-based devices. Strengthened by these results and its hydrophobizing properties, carbon has also started to be used as an electron transporting material (ETM), with excellent results on both rigid and flexible substrates. This review discusses the major advances and the updated state-of-the-art in the carbon-based PSC scenario, keeping a solid trajectory where the accessibility, low cost, high electrical conductivity, chemical stability and controllable porosity of carbon are highlighted and exploited in the design of upscalable hybrid solar cells. Broader contextToday, more than 75% of the world energy demand is met by traditional, non-sustainable energy resources, mainly based on coal, natural gas and oil. Photovoltaics represents a concrete action to mitigate fossil fuel consumption, and among all the developed solar cells, perovskite-based ones have shown the highest increase in terms of efficiency (currently above 25%). Halide perovskites, as a family of new-generation semiconductor materials, are also exploitable for light-emitting devices, photodetectors and memristors, but their use in photovoltaics gives rise to outstanding performances. Here, photogenerated charges pass through electron/hole transporting materials and are transferred to the external circuit by front and back electrodes. While the front electrode is a common conductive glass, many issues are now under study concerning the back electrode, traditionally made of gold. Indeed, replacing this expensive metal with a much cheaper alternative is vital for realizing affordable solar technologies. Carbon, in its multiple forms, represents the winning solution and the scientific community has recently shown its large scale processability, its power as a stability booster and some interesting effects at the perovskite/electrode interface. This review shows how carbon is becoming the winning ingredient for the scaling up and worldwide diffusion of perovskite solar cells.

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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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Operation Mechanism of Perovskite Quantum Dot Solar Cells Probed by Impedance Spectroscopy

Cited by 79 publications

References 61 publications

Impedance analysis of perovskite solar cells: a case study

Impedance analysis of perovskite solar cells: a case study

Carbon-based materials for stable, cheaper and large-scale processable perovskite solar cells

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

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