Positron Annihilation Lifetime Studies of <scp><scp>Nb</scp></scp>‐Doped <scp><scp>TiO</scp></scp>2, <scp><scp>Sn</scp><scp>O</scp></scp>2, and <scp><scp>Zr</scp><scp>O</scp></scp>2

Guagliardo, Paul; Vance, E. R.; Zhang, Zhaoming; Davis, Joel; Williams, James; Samarin, Sergey

doi:10.1111/j.1551-2916.2012.05157.x

Cited by 25 publications

(15 citation statements)

References 29 publications

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“…In addition to the three possible monovacancies in such materials, the number of possible binary complexes of intrinsic defects only is strongly increased compared to simple structures (e.g., divacancies, vacancy-antisite complexes). In ''simple'' complex oxides such as SnO 2 or ZrO 2 (Guagliardo et al, 2012) the situation is not as bad as in the multielement compounds, but the possibility of metal vacancy-oxygen vacancy complexes with multiple oxygen vacancies makes detailed defect identification difficult. For multimetal complex oxides (Uedono et al, 2002;Cheung et al, 2007;Keeble et al, 2007;Mackie et al, 2009;Gentils et al, 2010) these two challenges are combined, making identification even more difficult.…”

Section: A Materials With Complex Crystal Structuresmentioning

confidence: 99%

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Defect identification in semiconductors with positron annihilation: Experiment and theory

2013

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Positron annihilation spectroscopy is particularly suitable for studying vacancy-type defects in semiconductors. Combining state-of-the-art experimental and theoretical methods allows for detailed identification of the defects and their chemical surroundings. Also charge states and defect levels in the band gap are accessible. In this review the main experimental and theoretical analysis techniques are described. The usage of these methods is illustrated through examples in technologically important elemental and compound semiconductors. Future challenges include the analysis of noncrystalline materials and of transient defect-related phenomena.

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Section: A Materials With Complex Crystal Structuresmentioning

confidence: 99%

“…IV.A.3). Positron annihilation has been employed to investigate defects in these kinds of materials; see, e.g., Niki et al Guagliardo et al (2012), and Korhonen et al (2012). While the results are promising and pave the way for future studies, systematic studies are still missing.…”

Section: A Materials With Complex Crystal Structuresmentioning

confidence: 99%

Defect identification in semiconductors with positron annihilation: Experiment and theory

2013

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“…The spectrum arising from annihilations in the sample fits very well to a single line, indicating that only one exponential component with τ 0 = 183 ps is detected. Typically, in related materials the free positron lifetime is in the 170-to 180-ps range: 175-181 ps in SnO 2 [25,26], 170 ps in ZnO [27], and 184 ps in InN [28]. Cation vacancy lifetimes in these kinds of crystals are significantly higher than the bulk, usually by 40-80 ps.…”

Section: A Lifetime Spectroscopymentioning

confidence: 99%

Compensating vacancy defects in Sn- and Mg-dopedIn2O3

et al. 2014

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MBE-grown Sn-and Mg-doped epitaxial In 2 O 3 thin-film samples with varying doping concentrations have been measured using positron Doppler spectroscopy and compared to a bulk crystal reference. Samples were subjected to oxygen or vacuum annealing and the effect on vacancy type defects was studied. Results indicate that after oxygen annealing the samples are dominated by cation vacancies, the concentration of which changes with the amount of doping. In highly Sn-doped In 2 O 3 , however, these vacancies are not the main compensating acceptor. Vacuum annealing increases the size of vacancies in all samples, possibly by clustering them with oxygen vacancies.

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“…For Si, state-of-the-art models highlighted by Altermatt 54 and the latest Auger model 54 were applied in the simulation to accurately predict silicon characteristics. For SnO 2 , the key material parameters are determined from various papers [35][36][37][38][39][40] as listed in Table 1. Several essential models are employed to compute carrier transport including Fermi statistics, and Shockley-Reed-Hall models.…”

Section: Electrical Simulationsmentioning

confidence: 99%

Large area efficient interface layer free monolithic perovskite/homo-junction-silicon tandem solar cell with over 20% efficiency

Zheng

Lau

Mehrvarz

et al. 2018

Energy Environ. Sci.

203

186

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aMonolithic perovskite/silicon tandem solar cells show great promise for further efficiency enhancement for current silicon photovoltaic technology. In general, an interface (tunnelling or recombination) layer is usually required for electrical contact between the top and the bottom cells, which incurs higher fabrication costs and parasitic absorption. Most of the monolithic perovskite/Si tandem cells demonstrated use a hetero-junction silicon (Si) solar cell as the bottom cell, on small areas only. This work is the first to successfully integrate a low temperature processed (r150 1C) planar CH 3 NH 3 PbI 3 perovskite solar cell on a homo-junction silicon solar cell to achieve a monolithic tandem without the use of an additional interface layer on large areas (4 and 16 cm 2 ).Solution processed SnO 2 has been effective in providing dual functions in the monolithic tandem, serving as an ETL for the perovskite cell and as a recombination contact with the n-type silicon homo-junction solar cell that has a boron doped p-type (p++) front emitter. The SnO 2 /p++ Si interface is characterised in this work and the dominant transport mechanism is simulated using Sentaurus technology computer-aided design (TCAD) modelling. The champion device on 4 cm 2 achieves a power conversion efficiency (PCE) of 21.0% under reverse-scanning with a V OC of 1.68 V, a J SC of 16.1 mA cm À2 and a high FF of 78% yielding a steady-state efficiency of 20.5%. As our monolithic tandem device does not rely on the SnO 2 for lateral conduction, which is managed by the p++ emitter, up scaling to large areas becomes relatively straightforward. On a large area of 16 cm 2 , a reverse scan PCE of 17.6% and a steady-state PCE of 17.1% are achieved. To our knowledge, these are the most efficient perovskite/homo-junction-silicon tandem solar cells that are larger than 1 cm 2 . Most importantly, our results demonstrate for the first time that monolithic perovskite/silicon tandem solar cells can be achieved with excellent performance without the need for an additional interface layer. This work is relevant to the commercialisation of efficient large-area perovskite/homo-junction silicon tandem solar cells. Broader contextA simple approach for integrating a perovskite solar cell monolithically onto a Si solar cell is reported here. The first advantage of this approach is that it does not require additional fabrication of an additional interface layer between the perovskite and Si cell. The second advantage of this approach is that it is compatible with a homo-junction p-n Si solar cell, which is a common Si solar cell structure for commercial cells. The third advantage is that the entire sequence for the planar perovskite cell fabrication is done at low temperatures, minimising damage to the bottom Si solar cell. The fourth advantage is that the SnO 2 electron transport layer of the perovskite top cell also serves as a recombination contact with the silicon bottom cell. Finally, this monolithic tandem approach does not rely on the SnO 2 for lateral conducti...

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Positron Annihilation Lifetime Studies of Nb‐Doped TiO₂, SnO₂, and ZrO₂

Cited by 25 publications

References 29 publications

Defect identification in semiconductors with positron annihilation: Experiment and theory

Defect identification in semiconductors with positron annihilation: Experiment and theory

Compensating vacancy defects in Sn- and Mg-dopedIn2O3

Large area efficient interface layer free monolithic perovskite/homo-junction-silicon tandem solar cell with over 20% efficiency

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Positron Annihilation Lifetime Studies of Nb‐Doped TiO2, SnO2, and ZrO2

Cited by 25 publications

References 29 publications

Defect identification in semiconductors with positron annihilation: Experiment and theory

Defect identification in semiconductors with positron annihilation: Experiment and theory

Compensating vacancy defects in Sn- and Mg-dopedIn2O3

Large area efficient interface layer free monolithic perovskite/homo-junction-silicon tandem solar cell with over 20% efficiency

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Product

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Positron Annihilation Lifetime Studies of Nb‐Doped TiO₂, SnO₂, and ZrO₂