From Ultrafast to Ultraslow: Charge-Carrier Dynamics of Perovskite Solar Cells

Shi, Jiangjian; Li, Yiming; Li, Yusheng; Li, Dongmei; Luo, Yanhong; Wu, Haiming; Meng, Qingbo

doi:10.1016/j.joule.2018.04.010

Cited by 219 publications

(212 citation statements)

References 123 publications

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“…The former can measure extraction and transport of chargec arriers, and the latter provides information on their recombinationp rocess in the solar cell. [20,24,36,45] On the one hand, Figure 5c reveals the much faster photocurrent decay of the cell with TiO 2 /CsBr than with the TiO 2 ETL, which is indicativeo fm ore effective extraction and transport of chargec arriers in the former.S uch ad esirable feature mainly originates from the narrower CBM difference at the interface between TiO 2 /CsBr and CsPbIBr 2 ,w hich is beneficial to form am ore favorable energy band alignment,a llowing for energetic extraction and transfer of chargecarriers.…”

Section: Resultsmentioning

confidence: 93%

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr₂ Perovskite Solar Cells

et al. 2019

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Perovskite CsPbIBr2 is attracting ever‐increasing attention for carbon‐based, all‐inorganic solar cells, owing to its well‐balanced band gap and stability features. However, significant interfacial recombination of charge carriers in solar cells fabricated with this active layer, which is intrinsically associated with the unwanted conduction band misalignment between CsPbIBr2 and the commonly used TiO2 electron transport layer, has limited power conversion efficiency (PCE) values. Herein, we demonstrate successful conduction band alignment engineering at the TiO2/CsPbIBr2 heterojunction by modifying TiO2 with CsBr clusters. Such modification triggers a beneficial increase in the conduction band minimum (CBM) of TiO2 from −4.00 to −3.81 eV and decreases the work function from 4.11 to 3.86 eV, thus promoting favorable band alignment at the heterojunction, suppressing recombination, and improving extraction and transport of charge carriers. As a result, the carbon‐based, all‐inorganic CsPbIBr2 solar cells exhibit over 20 % enhancement in average PCE. The champion device achieves a PCE of 10.71 %, a record among pure CsPbIBr2‐based cells, open‐circuit voltage of 1.261 V, and excellent stability.

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Section: Resultsmentioning

confidence: 93%

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr₂ Perovskite Solar Cells

et al. 2019

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“…For the perovskite solar cell, steady-state energy conversion involves a variety of processes including charge generation, charge transfer and transport within the bulk absorber and the charge transporting layers (CTLs), charge recombination at the bulk and interface, and even photoelectric hysteresis. 16 A series of optical and electrical transient methods has been exploited to probe these dynamics processes in a wide time ranging from sub-picosecond to even hours to shed light on the working mechanisms and charge loss mechanism of this emerging material and cell. Compared to the advanced ultrafast optics measurements, [17][18][19][20][21][22][23][24][25][26][27][28][29] perturbation electrical transients (e.g.…”

Section: Introductionmentioning

confidence: 99%

Exploiting Electrical Transients to Quantify Charge Loss in Solar Cells

Shi

et al. 2020

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Electrical transients enabled by optical excitation and electric detection provide a distinctive opportunity to study the charge transport, recombination and even the hysteresis of a solar cell in a much wider time window ranging from nanoseconds to seconds. However, controversies on how to exploit these investigations to unravel the charge loss mechanism of the cell have been ongoing. Herein, a new methodology of quantifying the charge loss within the bulk absorber or at the interfaces and the defect properties of junction solar cells has been proposed after the conventional tail-state framework is firstly demonstrated to be unreasonable. This methodology has been successfully applied in the study of commercialized silicon and emerging Cu 2 ZnSn(S, Se) 4 and perovskite solar cells herein and should be universal to other photovoltaic device systems with similar structures. Overall, this work provides an alluring route for comprehensive investigation of dynamic physics processes and charge loss mechanism of junction solar cells and possesses potential applications for other optoelectronic devices.

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“…Besides higher conductivity and hole mobility,w es peculate that more efficient hole extraction and reduced charge recombination would occur at the perovskite/HTM interface. Thus,togain more insights into charge transfer dynamics,the electrical impedance spectra (EIS) [22] were recorded, showing as maller charge transfer resistance (R rt ;F igure S11b). The photoluminescence (PL) spectra and time-resolved photoluminescence (TRPL) kinetic data [23] revealed as tronger PL quenching effect and the shortened lifetime by doping with POM@Cu-BTC ( Figure S12).…”

Section: Angewandte Chemiementioning

confidence: 99%

Self‐Assembly of Hybrid Oxidant POM@Cu‐BTC for Enhanced Efficiency and Long‐Term Stability of Perovskite Solar Cells

et al. 2019

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The controllable oxidation of spiro-OMeTAD and improving the stability of hole-transport materials (HTMs) layer are crucial for good performance and stability of perovskite solar cells (PSCs). Herein, we report an efficient hybrid polyoxometalate@metal-organic framework (POM@MOF) material, [Cu 2 (BTC) 4/3 -(H 2 O) 2 ] 6 [H 3 PMo 12 O 40 ] 2 or POM@Cu-BTC,f or the oxidation of spiro-OMeTAD with Li-TFSI and TBP.W hen POM@Cu-BTC is introduced to the HTM layer as ad opant, the PSCs achieve as uperior fill factor of 0.80 and enhanced power conversion efficiency 21.44 %, as well as improved long-term stability in an ambient atmosphere without encapsulation. The enhanced performance is attributed to the oxidation activity of POM anions and solid-state nanoparticles.T herefore,t his researchpresents afacile way by using hybrid porous materials to accelerate oxidation of spiro-OMeTAD,f urther improving the efficiency and stability of PSCs.Organic-inorganic lead halide perovskites have been demonstrated as an immensely promising photovoltaic material, because of their tunable band gaps,strong optical absorption, as well as low-cost solution-based fabrication processes. [1] In particular,the power conversion efficiency (PCE) of PSCs has advanced rapidly to above 25.2 %, approaching the performance of crystalline silicon solar cells. [2] Even though the efficiencies of PSCs are sufficient for commercialization, their large-scale preparation and practical application are still limited by ap oor long-term stability mainly stem from perovskite or HTM layers. [3] Thestability of perovskite layer may be improved by reinforcing intrinsic stability,employing surface passivation, and using appropriate interlayers. [4] However,e ffectively improving and controlling the stability of the HTM layer are less studied which is also important for whole device.A mong the commonly used HTMs, [5] small organic molecule spiro-OMeTAD,h as wildly proven as the dominant HTM for highly efficient PSCs,mainly ascribing to high solubility and well-matched energy level. [6] However, many practical results testify that pristine spiro-OMeTAD has low conductivity,m oderate hole-mobility and long oxidation time in the order of days,restricting its functionality in highefficiency PSCs. [6c] To solve these problems,lithium bis(trifluoromethanesulfonyl)-imide (Li-TFSI) and 4-tert-butylpyride (TBP) are commonly used bi-dopants to enhance the performance of spiro-OMeTAD-based devices. [7] However,t here are some remaining challenges for these systems. [6c, 8] Specifically, deliquescent and hygroscopic Li-TFSI reacts with water molecules and eventually degrades the HTM and perovskite layers,a nd its ion behavior also strongly affects hysteresis of PSCs. [5b, 9] Therefore,simultaneously accelerating controllable oxidation process of spiro-OMeTAD and improving conductivity,a sw ell as diminishing the influence of Li-TFSI by as imple and efficient strategy will be the key points to the commercialization of PSCs.Polyoxometalates (POMs), at ype of metal oxo-clust...

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From Ultrafast to Ultraslow: Charge-Carrier Dynamics of Perovskite Solar Cells

Cited by 219 publications

References 123 publications

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr₂ Perovskite Solar Cells

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr₂ Perovskite Solar Cells

Exploiting Electrical Transients to Quantify Charge Loss in Solar Cells

Self‐Assembly of Hybrid Oxidant POM@Cu‐BTC for Enhanced Efficiency and Long‐Term Stability of Perovskite Solar Cells

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From Ultrafast to Ultraslow: Charge-Carrier Dynamics of Perovskite Solar Cells

Cited by 219 publications

References 123 publications

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr2 Perovskite Solar Cells

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr2 Perovskite Solar Cells

Exploiting Electrical Transients to Quantify Charge Loss in Solar Cells

Self‐Assembly of Hybrid Oxidant POM@Cu‐BTC for Enhanced Efficiency and Long‐Term Stability of Perovskite Solar Cells

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Product

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Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr₂ Perovskite Solar Cells

Band Alignment Engineering Towards High Efficiency Carbon‐Based Inorganic Planar CsPbIBr₂ Perovskite Solar Cells