Logotyp: till Uppsala universitets webbplats

uu.sePublikationer från Uppsala universitet
Ändra sökning
Länk till posten
Permanent länk

Direktlänk
Stolt, Lars
Publikationer (10 of 100) Visa alla publikationer
Pearson, P., Keller, J., Stolt, L. & Platzer Björkman, C. (2023). Investigating the Role of Ag and Ga Content in the Stability of Wide-Gap (Ag,Cu)(In,Ga)Se-2 Thin-Film Solar Cells. Physica status solidi. B, Basic research, 260(7), Article ID 2300170.
Öppna denna publikation i ny flik eller fönster >>Investigating the Role of Ag and Ga Content in the Stability of Wide-Gap (Ag,Cu)(In,Ga)Se-2 Thin-Film Solar Cells
2023 (Engelska)Ingår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 260, nr 7, artikel-id 2300170Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The stability of thin-film solar cells spanning a wide range of compositions within the (Ag,Cu)(In,Ga)Se-2 material system is evaluated over time, after dry-heat annealing and after light soaking, and the role of Ag and Ga content is explored. Ag-free CuInSe2 is relatively stable to annealing and storage, while Cu(In,Ga)Se-2 suffers a degradation of fill factor and carrier collection. High-Ga (Ag,Cu)(In,Ga)Se-2 suffers degradation of carrier collection after prolonged annealing, reducing the short-circuit current by approximate to 12%. Ga-free (Ag,Cu)InSe2 loses up to a third of open-circuit voltage and a quarter of fill factor after all treatments are applied. All samples suffer voltage losses after light soaking, with the Ga-free devices losing up to 50 mV and those containing Ga losing up to 90 mV. Ag incorporation leads to a significant reduction in doping, and a significant increase in the response of doping to treatments, with the depletion width of (Ag,Cu)(In,Ga)Se-2 samples expanding from approximate to 0.1 mu m as-grown to beyond 1.0 mu m after all treatments, compared to the Cu(In,Ga)Se-2 sample variation of approximate to 0.1-0.3 mu m. Connections between Ag content, doping instability, and performance degradation are discussed.

Ort, förlag, år, upplaga, sidor
Wiley-VCH Verlagsgesellschaft, 2023
Nyckelord
(Ag, Cu)(In, Ga)Se-2, Cu(In, stability, stoichiometry, wide-gap chalcopyrites
Nationell ämneskategori
Den kondenserade materiens fysik Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:uu:diva-511086 (URN)10.1002/pssb.202300170 (DOI)000987151600001 ()
Forskningsfinansiär
Energimyndigheten, 48479-1Vetenskapsrådet, 201904793
Tillgänglig från: 2023-09-07 Skapad: 2023-09-07 Senast uppdaterad: 2023-09-07Bibliografiskt granskad
Keller, J., Stolt, L., Törndahl, T. & Edoff, M. (2023). Silver Alloying in Highly Efficient CuGaSe2 Solar Cells with Different Buffer Layers. Solar RRL, 7(12), Article ID 2300208.
Öppna denna publikation i ny flik eller fönster >>Silver Alloying in Highly Efficient CuGaSe2 Solar Cells with Different Buffer Layers
2023 (Engelska)Ingår i: Solar RRL, E-ISSN 2367-198X, Vol. 7, nr 12, artikel-id 2300208Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This study evaluates the effect of silver alloying, stoichiometry, and deposition temperature of wide-gap (Ag,Cu)GaSe2 (ACGS) absorber films for solar cell applications. Devices using a standard CdS buffer exhibit a strong anticorrelation between the open-circuit voltage (V-OC) and short-circuit current density (J(SC)), with V-OC decreasing and J(SC) increasing toward stoichiometric absorber composition. Increasing the ACGS deposition temperature leads to larger grains and improved J(SC), while V-OC is not affected. By adding more silver to the absorber (maximum tested [Ag]/([Ag]+[Cu]) [AAC] = 0.4), the widening of the space charge region (SCR) significantly enhances carrier collection. Experimental quantum efficiency spectra can be accurately simulated when assuming a very low diffusion length and perfect collection in the SCR. The highest efficiency of 8.3% (without antireflection coating [ARC]) is reached for an absorber with AAC = 0.4 grown at 600 degrees C. Replacing CdS by a (Zn,Sn)O buffer with lower electron affinity strongly mitigates interface recombination. Moreover, the V-OC-J(SC) anticorrelation is not evident anymore and the highest efficiency of 11.2% (11.6% w/ARC, V-OC = 985 mV, J(SC) = 18.6 mA cm(-2), fill factor = 61.0%) is reached for a close-stoichiometric ACGS solar cell with AAC = 0.4 processed at 650 degrees C.

Ort, förlag, år, upplaga, sidor
John Wiley & Sons, 2023
Nyckelord
CIGS, CuGaSe2, silver alloying, tandem devices, wide-gap solar cells
Nationell ämneskategori
Den kondenserade materiens fysik
Identifikatorer
urn:nbn:se:uu:diva-511040 (URN)10.1002/solr.202300208 (DOI)000981273300001 ()
Forskningsfinansiär
EU, Horisont 2020, 101075626Energimyndigheten, 2020-009335
Tillgänglig från: 2023-09-06 Skapad: 2023-09-06 Senast uppdaterad: 2023-09-06Bibliografiskt granskad
Keller, J., Aboulfadl, H., Stolt, L., Donzel-Gargand, O. & Edoff, M. (2022). Rubidium Fluoride Absorber Treatment for Wide-Gap (Ag,Cu)(In,Ga)Se-2 Solar Cells. Solar RRL, 6(6), Article ID 2200044.
Öppna denna publikation i ny flik eller fönster >>Rubidium Fluoride Absorber Treatment for Wide-Gap (Ag,Cu)(In,Ga)Se-2 Solar Cells
Visa övriga...
2022 (Engelska)Ingår i: Solar RRL, E-ISSN 2367-198X, Vol. 6, nr 6, artikel-id 2200044Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This contribution studies the potential of an RbF postdeposition treatment (RbF-PDT) of wide-gap (Ag,Cu)(In,Ga)Se-2 (ACIGS) absorbers to improve the corresponding solar cell performance. While a higher open-circuit voltage (V-OC) and short-circuit current density are achieved, a lower fill factor (FF) is observed for most of the devices subjected to an RbF-PDT. However, the drop in FF can be avoided for some close-stoichiometric samples, leading to maximum efficiencies beyond 16% (without antireflection coating) at a bandgap energy (E-g) of 1.43 eV. For off-stoichiometric ACIGS, a record V-OC value of 926 mV at E-g = 1.44 eV is reached. Lower V-OC deficits likely require enhanced bulk quality of wide-gap chalcopyrite absorbers. Extensive material analysis shows that the heavy alkali PDT of ACIGS with high Ag and Ga contents leads to similar absorber modifications as commonly observed for low-gap Cu(In,Ga)Se-2 (CIGS). Rubidium is continuously distributed at "internal" (grain boundaries) and "external" (buffer and back contact) absorber interfaces. The results indicate that Rb diffusion into the absorber bulk (including 1:1:2 and 1:3:5 compounds) is restricted. Furthermore, the formation of a very thin RbInSe2 surface layer is suggested. It remains open, which effects alter the device characteristics after RbF-PDT.

Ort, förlag, år, upplaga, sidor
John Wiley & SonsWILEY-V C H VERLAG GMBH, 2022
Nyckelord
(Ag, Cu)(In, Ga)Se-2 (ACIGS), Cu(In, Ga)Se-2 (CIGS), RbF postdeposition treatment (RbF-PDT), stoichiometry, wide-gap chalcopyrite
Nationell ämneskategori
Energisystem
Identifikatorer
urn:nbn:se:uu:diva-483979 (URN)10.1002/solr.202200044 (DOI)000760296200001 ()
Forskningsfinansiär
Stiftelsen för strategisk forskning (SSF), RMA15-0030Energimyndigheten, P50992-1Energimyndigheten, 2020-009335
Tillgänglig från: 2022-09-07 Skapad: 2022-09-07 Senast uppdaterad: 2024-01-15Bibliografiskt granskad
Pearson, P., Keller, J., Stolt, L., Edoff, M. & Platzer Björkman, C. (2022). The Effect of Absorber Stoichiometry on the Stability of Widegap (Ag,Cu)(In,Ga)Se2 Solar Cells. Physica status solidi. B, Basic research, 259(11), Article ID 2200104.
Öppna denna publikation i ny flik eller fönster >>The Effect of Absorber Stoichiometry on the Stability of Widegap (Ag,Cu)(In,Ga)Se2 Solar Cells
Visa övriga...
2022 (Engelska)Ingår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 259, nr 11, artikel-id 2200104Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

(Ag,Cu)(In,Ga)Se2 solar cells with bandgaps of ≈1.45 eV with a large spread in absorber stoichiometry are characterized with the intention of assessing the effect of composition on the stability of the devices. This material is observed to have a poor diffusion length, leading to very strong dependence upon the depletion region width for charge carrier collection. The depletion width is observed to depend strongly upon the stoichiometry value and shrinks significantly after an initial period of dark storage. It is also seen that the depletion width can be varied strongly through light-soaking and dry-heat treatments, with prolonged annealing leading to detrimental contraction and light soaking leading to expansion which increases current collection. The extent of depletion width variation in response to the treatments is also clearly linked to absorber stoichiometry. Consequently, the device performance, particularly the current output, exhibits a stoichiometry dependence and is considerably affected after each round of treatment. Possible causes of this behavior are discussed.

Ort, förlag, år, upplaga, sidor
Wiley-VCH Verlagsgesellschaft, 2022
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:uu:diva-496436 (URN)10.1002/pssb.202200104 (DOI)000847103800001 ()
Forskningsfinansiär
Energimyndigheten, 48479−1Vetenskapsrådet, 2019−04793
Tillgänglig från: 2023-02-13 Skapad: 2023-02-13 Senast uppdaterad: 2023-02-13Bibliografiskt granskad
Keller, J., Stolt, L., Donzel-Gargand, O., Kubart, T. & Edoff, M. (2022). Wide-Gap Chalcopyrite Solar Cells with Indium Oxide-Based Transparent Back Contacts. Solar RRL, 6(8), Article ID 2200401.
Öppna denna publikation i ny flik eller fönster >>Wide-Gap Chalcopyrite Solar Cells with Indium Oxide-Based Transparent Back Contacts
Visa övriga...
2022 (Engelska)Ingår i: Solar RRL, E-ISSN 2367-198X, Vol. 6, nr 8, artikel-id 2200401Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Herein, the performance of wide-gap Cu(In,Ga)Se-2 (CIGS) and (Ag,Cu)(In,Ga)Se-2 (ACIGS) solar cells with In2O3:Sn (ITO) and In2O3:H (IOH) as transparent back contact (TBC) materials is evaluated. Since both TBCs restrict sodium in-diffusion from the glass substrate, fine-tuning of a NaF precursor layer is crucial. It is found that the optimum Na supply is lower for ACIGS than for CIGS samples. An excessive sodium amount deteriorates the solar cell performance, presumably by facilitating GaOx growth at the TBC/absorber interface. The efficiency (eta) further depends on the absorber stoichiometry, with highest fill factors (and eta) reached for close-stoichiometric compositions. An ACIGS solar cell with eta = 12% at a bandgap of 1.44 eV is processed, using IOH as a TBC. The best CIGS device reaches eta = 11.2% on ITO. Due to its very high infrared transparency, IOH is judged superior to ITO for implementation in a top cell of a tandem device. However, while ITO layers maintain their conductivity, IOH films show an increased sheet resistance after absorber deposition. Chemical investigations indicate that incorporation of Se during the initial stage of absorber processing may be responsible for the deteriorated conductivity of the IOH back contact in the final device.

Ort, förlag, år, upplaga, sidor
John Wiley & SonsWiley, 2022
Nyckelord
ACIGS, CIGS, tandem devices, transparent back contact, wide-gap chalcopyrites
Nationell ämneskategori
Materialkemi
Identifikatorer
urn:nbn:se:uu:diva-483588 (URN)10.1002/solr.202200401 (DOI)000803744900001 ()
Forskningsfinansiär
Stiftelsen för strategisk forskning (SSF), RMA15-0030Energimyndigheten, P50992-1Energimyndigheten, 2020-009335
Tillgänglig från: 2022-08-31 Skapad: 2022-08-31 Senast uppdaterad: 2024-01-15Bibliografiskt granskad
Calnan, S., Bagacki, R., Bao, F., Dorbandt, I., Kemppainen, E., Schary, C., . . . Bayrak Pehlivan, I. (2021). Development of Various Photovoltaic‐Driven Water Electrolysis Technologies for Green Solar Hydrogen Generation. Solar RRL, 6(5), Article ID 2100479.
Öppna denna publikation i ny flik eller fönster >>Development of Various Photovoltaic‐Driven Water Electrolysis Technologies for Green Solar Hydrogen Generation
Visa övriga...
2021 (Engelska)Ingår i: Solar RRL, E-ISSN 2367-198X, Vol. 6, nr 5, artikel-id 2100479Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Direct solar hydrogen generation via a combination of photovoltaics (PV) and water electrolysis can potentially ensure a sustainable energy supply while minimizing greenhouse emissions. The PECSYS project aims at demonstrating asolar-driven electrochemical hydrogen generation system with an area >10 m2 with high efficiency and at reasonable cost. Thermally integrated PV electrolyzers(ECs) using thin-film silicon, undoped, and silver-doped Cu(In,Ga)Se2 and silicon heterojunction PV combined with alkaline electrolysis to form one unit are developed on a prototype level with solar collection areas in the range from 64 to2600 cm2 with the solar-to-hydrogen (StH) efficiency ranging from 4 to 13%. Electrical direct coupling of PV modules to a proton exchange membrane EC test the effects of bifacially (730 cm2 solar collection area) and to study the long-term operation under outdoor conditions (10 m2 collection area) is also investigated. In both cases, StH efficiencies exceeding 10% can be maintained over the test periods used. All the StH efficiencies reported are based on measured gas outflow using mass flow meters.

Ort, förlag, år, upplaga, sidor
John Wiley & Sons, 2021
Nyckelord
direct coupling, direct solar hydrogen generation, low-temperature electrolyzers, photovoltaic-driven water electrolysis
Nationell ämneskategori
Energisystem
Identifikatorer
urn:nbn:se:uu:diva-496284 (URN)10.1002/solr.202100479 (DOI)000697629100001 ()
Forskningsfinansiär
Europeiska kommissionen
Tillgänglig från: 2023-02-09 Skapad: 2023-02-09 Senast uppdaterad: 2023-04-12Bibliografiskt granskad
Bayrak Pehlivan, I., Atak, G., Niklasson, G., Stolt, L., Edoff, M. & Edvinsson, T. (2021). Electrochromic solar water splitting using a cathodic WO3 electrocatalyst. Nano Energy, 81, Article ID 105620.
Öppna denna publikation i ny flik eller fönster >>Electrochromic solar water splitting using a cathodic WO3 electrocatalyst
Visa övriga...
2021 (Engelska)Ingår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 81, artikel-id 105620Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Solar-driven water splitting is an emerging technology with high potential to generate fuel cleanly and sustainably. In this work, we show that WO3 can be used as a cathodic electrocatalyst in combination with (Ag,Cu) InGaSe2 solar cell modules to produce hydrogen and provide electrochromic functionality to water splitting devices. This electrochromic effect can be used to monitor the charge state or performance of the catalyst for process control or for controlling the temperature and absorbed heat due to tunable optical modulation of the electrocatalyst. WO3 films coated on Ni foam, using a wide range of different sputtering conditions, were investigated as cathodic electrocatalysts for the water splitting reaction. The solar-to-hydrogen (STH) efficiency of solar-driven water electrolysis was extracted using (Ag,Cu)InGaSe2 solar cell modules with a cell band gap varied in between 1.15 and 1.25 eV with WO3 on Ni foam-based electrolyzers and yielded up to 13% STH efficiency. Electrochromic properties during water electrolysis were characterized for the WO3 films on transparent substrate (indium tin oxide). Transmittance varied between 10% and 78% and the coloration efficiency at a wavelength of 528 nm and the overpotential of 400 mV was 40 cm(2) C-1. Hydrogen ion consumption in ion intercalation for electrochromic and hydrogen gas production for water electrolysis processes was discussed.

Ort, förlag, år, upplaga, sidor
ElsevierELSEVIER, 2021
Nyckelord
Electrochromism, Hydrogen evolution reaction, Water splitting, WO3, Site saturation
Nationell ämneskategori
Materialkemi
Identifikatorer
urn:nbn:se:uu:diva-442593 (URN)10.1016/j.nanoen.2020.105620 (DOI)000639191300015 ()
Forskningsfinansiär
EU, Horisont 2020, 735218EnergimyndighetenVetenskapsrådet, 2015-03814
Tillgänglig från: 2021-05-24 Skapad: 2021-05-24 Senast uppdaterad: 2024-01-15Bibliografiskt granskad
Keller, J., Pearson, P., Shariati Nilsson, N., Stolt, O., Stolt, L. & Edoff, M. (2021). Performance Limitations of Wide-Gap (Ag,Cu)(In,Ga)Se2 Thin-Film Solar Cells. Solar RRL, 5(9), Article ID 2100403.
Öppna denna publikation i ny flik eller fönster >>Performance Limitations of Wide-Gap (Ag,Cu)(In,Ga)Se2 Thin-Film Solar Cells
Visa övriga...
2021 (Engelska)Ingår i: Solar RRL, E-ISSN 2367-198X, Vol. 5, nr 9, artikel-id 2100403Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The effect of absorber stoichiometry in (Ag,Cu)(In,Ga)Se2(ACIGS) solar cells withbandgaps (Eg) > 1.40 eV is studied on a large sample set. It is conrmed thatmoving away in composition from ternary AgGaSe2by simultaneous reduction inGa and Ag content widens the chalcopyrite single-phase region and therebyreduces the amount of ordered vacancy compounds (OVCs). As a consequence, adistortion in currentvoltage characteristics, ascribed to OVCs at the back contact,can be successfully avoided. A clear anticorrelation between open-circuit voltage(VOC) and short-circuit current density (JSC) is detected with varying absorberstoichiometry, showing decreasingVOCand increasingJSCvalues for [I]/[III] > 0.9.Capacitance proling reveals that the absorber doping gradually decreases towardstoichiometric composition, eventually leading to complete depletion. It isobserved that only such fully depleted samples exhibit perfect carrier collection,evidencing a very low diffusion length in wide-gap ACIGS lms. The results indicatethat OVCs at the surface play a minor or passive role for device performance.Finally, a solar cell withVOC¼ 0.916 V atEg¼ 1.46 eV is measured, which is, to thebest of our knowledge, the highest value reported for this bandgap to date.

Ort, förlag, år, upplaga, sidor
John Wiley & Sons, 2021
Nyckelord
(Ag, Cu)(In, Ga)Se 2, Cu(In, Ga)Se 2, ordered vacancy compounds, stoichiometry, wide-gap chalcopyrites
Nationell ämneskategori
Annan elektroteknik och elektronik
Identifikatorer
urn:nbn:se:uu:diva-451080 (URN)10.1002/solr.202100403 (DOI)000677768300001 ()
Forskningsfinansiär
Stiftelsen för strategisk forskning (SSF), RMA15-0030Energimyndigheten, P50992-1
Tillgänglig från: 2021-08-23 Skapad: 2021-08-23 Senast uppdaterad: 2023-10-05Bibliografiskt granskad
Larsson, F., Stolt, L., Hultqvist, A., Edoff, M., Keller, J. & Törndahl, T. (2020). Atomic Layer Deposition of Ternary Compounds on Cu(In,Ga)Se2: An In Situ Quartz Crystal Microbalance Study. ACS Applied Energy Materials, 3(7), 7208-7215
Öppna denna publikation i ny flik eller fönster >>Atomic Layer Deposition of Ternary Compounds on Cu(In,Ga)Se2: An In Situ Quartz Crystal Microbalance Study
Visa övriga...
2020 (Engelska)Ingår i: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 3, nr 7, s. 7208-7215Artikel i tidskrift (Refereegranskat) Published
Ort, förlag, år, upplaga, sidor
American Chemical Society (ACS), 2020
Nationell ämneskategori
Teknik och teknologier
Identifikatorer
urn:nbn:se:uu:diva-416749 (URN)10.1021/acsaem.0c01284 (DOI)000557375200131 ()
Tillgänglig från: 2020-08-03 Skapad: 2020-08-03 Senast uppdaterad: 2020-12-15Bibliografiskt granskad
Keller, J., Stolt, L., Sopiha, K., Larsen, J. K., Riekehr, L. & Edoff, M. (2020). On the Paramount Role of Absorber Stoichiometry in (Ag,Cu)(In,Ga)Se2 Wide‐Gap Solar Cells. Solar RRL, 4(12), Article ID 2000508.
Öppna denna publikation i ny flik eller fönster >>On the Paramount Role of Absorber Stoichiometry in (Ag,Cu)(In,Ga)Se2 Wide‐Gap Solar Cells
Visa övriga...
2020 (Engelska)Ingår i: Solar RRL, E-ISSN 2367-198X, Vol. 4, nr 12, artikel-id 2000508Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

This contribution evaluates the effect of absorber off‐stoichiometry in wide‐gap (Ag,Cu)(In,Ga)Se2 (ACIGS) solar cells. It is found that ACIGS films show an increased tendency to form ordered vacancy compounds (OVCs) with increasing Ga and Ag contents. Very little tolerance to off‐stoichiometry is detected for absorber compositions giving the desired properties of 1) an optimum bandgap (EG) for a top cell in tandem devices (EG = 1.6–1.7 eV) and at the same time 2) a favorable band alignment with a CdS buffer layer. Herein, massive formation of either In‐ or Ga‐enriched OVC patches is found for group I‐poor ACIGS. As a consequence, carrier transport and charge collection are significantly impeded in corresponding solar cells. The transport barrier appears to be increasing with storage time, questioning the long‐term stability of wide‐gap ACIGS solar cells. Furthermore, the efficiency of samples with very high Ga and Ag contents depends on the voltage sweep direction. It is proposed that the hysteresis behavior is caused by a redistribution of mobile Na ions in the 1:1:2 absorber lattice upon voltage bias. Finally, a broader perspective on OVC formation in the ACIGS system is provided and fundamental limitations for wide‐gap ACIGS solar cells are discussed. 

Nationell ämneskategori
Materialteknik
Identifikatorer
urn:nbn:se:uu:diva-429873 (URN)10.1002/solr.202000508 (DOI)000573502400001 ()
Forskningsfinansiär
Stiftelsen för strategisk forskning (SSF), RMA15‐0030Energimyndigheten, P43238‐1
Tillgänglig från: 2021-01-05 Skapad: 2021-01-05 Senast uppdaterad: 2021-01-26Bibliografiskt granskad
Organisationer

Sök vidare i DiVA

Visa alla publikationer