Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications

Sara Lena Josefin Engberg, Swathi Murthy, Simón López Mariño, Ole Hansen, Guggi Kofod, Jørgen Schou

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsResearchpeer-review

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Abstract

The kesterite material, Cu2ZnSnS4 (CZTS), has in the preceding ten years been investigated and developed as a new Earth-abundant material for solar cells. The interest in this inorganic semiconductor originates in its optimal energy band gap of approx. 1.5 eV, high absorption coefficient, and the high material abundance and low toxicity of all elements included. The current challenges are related to unavoidable antisite disordering stemming from the chemical similarity of the cations, which causes bulk defects and lowers the open-circuit voltage detrimentally. This, however, did not restrict the “cousin”-material, CuInGaSe2 (CIGS), which is currently one of the main thin-film photovoltaic (PV) technologies on the market. In this work, CZTS thin films have been fabricated by solution-processing, which allows relatively fast and inexpensive deposition when compared to vacuum-processed films. The nanoparticles are synthesized by the hot-injection method by mixing targeted ratios of metal salts with sulfur in diethylene glycol, resulting in a phase-pure CZTS material [1]. Inks are formulated by dispersing the particles in ethanol and water using a suitable dispersing agent. The solvents used allow that alkali metal chloride salts can also be dissolved in controllable amounts, which we have found enhances grain growth in the films during the subsequent annealing step. A Sono-tek spray-coating system with ultrasonic atomization is used. We investigate the effect of ink concentration, and spray-coating conditions, including spray power, flow rate from syringe pump, and time between consecutive spray layers. The films are annealed in a tube furnace, and to avoid decomposing the material into secondary phases, a graphite box is used to enable an overpressure of sulfur and tin-sulfide. The annealed, spray-coated films are characterized by scanning electron microscopy (SEM), optical microscopy, and Dektak profilometry.
Original languageEnglish
Title of host publicationBook of Abstracts Sustain 2017
Number of pages1
PublisherTechnical University of Denmark
Publication date2017
Article numberE-14
Publication statusPublished - 2017
EventSustain 2017 - Technical University of Denmark, Kgs. Lyngby, Denmark
Duration: 6 Dec 20176 Dec 2017

Conference

ConferenceSustain 2017
LocationTechnical University of Denmark
CountryDenmark
CityKgs. Lyngby
Period06/12/201706/12/2017

Cite this

Engberg, S. L. J., Murthy, S., Mariño, S. L., Hansen, O., Kofod, G., & Schou, J. (2017). Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications. In Book of Abstracts Sustain 2017 [E-14] Technical University of Denmark.
Engberg, Sara Lena Josefin ; Murthy, Swathi ; Mariño, Simón López ; Hansen, Ole ; Kofod, Guggi ; Schou, Jørgen. / Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications. Book of Abstracts Sustain 2017. Technical University of Denmark, 2017.
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abstract = "The kesterite material, Cu2ZnSnS4 (CZTS), has in the preceding ten years been investigated and developed as a new Earth-abundant material for solar cells. The interest in this inorganic semiconductor originates in its optimal energy band gap of approx. 1.5 eV, high absorption coefficient, and the high material abundance and low toxicity of all elements included. The current challenges are related to unavoidable antisite disordering stemming from the chemical similarity of the cations, which causes bulk defects and lowers the open-circuit voltage detrimentally. This, however, did not restrict the “cousin”-material, CuInGaSe2 (CIGS), which is currently one of the main thin-film photovoltaic (PV) technologies on the market. In this work, CZTS thin films have been fabricated by solution-processing, which allows relatively fast and inexpensive deposition when compared to vacuum-processed films. The nanoparticles are synthesized by the hot-injection method by mixing targeted ratios of metal salts with sulfur in diethylene glycol, resulting in a phase-pure CZTS material [1]. Inks are formulated by dispersing the particles in ethanol and water using a suitable dispersing agent. The solvents used allow that alkali metal chloride salts can also be dissolved in controllable amounts, which we have found enhances grain growth in the films during the subsequent annealing step. A Sono-tek spray-coating system with ultrasonic atomization is used. We investigate the effect of ink concentration, and spray-coating conditions, including spray power, flow rate from syringe pump, and time between consecutive spray layers. The films are annealed in a tube furnace, and to avoid decomposing the material into secondary phases, a graphite box is used to enable an overpressure of sulfur and tin-sulfide. The annealed, spray-coated films are characterized by scanning electron microscopy (SEM), optical microscopy, and Dektak profilometry.",
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Engberg, SLJ, Murthy, S, Mariño, SL, Hansen, O, Kofod, G & Schou, J 2017, Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications. in Book of Abstracts Sustain 2017., E-14, Technical University of Denmark, Sustain 2017, Kgs. Lyngby, Denmark, 06/12/2017.

Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications. / Engberg, Sara Lena Josefin; Murthy, Swathi; Mariño, Simón López; Hansen, Ole; Kofod, Guggi; Schou, Jørgen.

Book of Abstracts Sustain 2017. Technical University of Denmark, 2017. E-14.

Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsResearchpeer-review

TY - ABST

T1 - Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications

AU - Engberg, Sara Lena Josefin

AU - Murthy, Swathi

AU - Mariño, Simón López

AU - Hansen, Ole

AU - Kofod, Guggi

AU - Schou, Jørgen

PY - 2017

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N2 - The kesterite material, Cu2ZnSnS4 (CZTS), has in the preceding ten years been investigated and developed as a new Earth-abundant material for solar cells. The interest in this inorganic semiconductor originates in its optimal energy band gap of approx. 1.5 eV, high absorption coefficient, and the high material abundance and low toxicity of all elements included. The current challenges are related to unavoidable antisite disordering stemming from the chemical similarity of the cations, which causes bulk defects and lowers the open-circuit voltage detrimentally. This, however, did not restrict the “cousin”-material, CuInGaSe2 (CIGS), which is currently one of the main thin-film photovoltaic (PV) technologies on the market. In this work, CZTS thin films have been fabricated by solution-processing, which allows relatively fast and inexpensive deposition when compared to vacuum-processed films. The nanoparticles are synthesized by the hot-injection method by mixing targeted ratios of metal salts with sulfur in diethylene glycol, resulting in a phase-pure CZTS material [1]. Inks are formulated by dispersing the particles in ethanol and water using a suitable dispersing agent. The solvents used allow that alkali metal chloride salts can also be dissolved in controllable amounts, which we have found enhances grain growth in the films during the subsequent annealing step. A Sono-tek spray-coating system with ultrasonic atomization is used. We investigate the effect of ink concentration, and spray-coating conditions, including spray power, flow rate from syringe pump, and time between consecutive spray layers. The films are annealed in a tube furnace, and to avoid decomposing the material into secondary phases, a graphite box is used to enable an overpressure of sulfur and tin-sulfide. The annealed, spray-coated films are characterized by scanning electron microscopy (SEM), optical microscopy, and Dektak profilometry.

AB - The kesterite material, Cu2ZnSnS4 (CZTS), has in the preceding ten years been investigated and developed as a new Earth-abundant material for solar cells. The interest in this inorganic semiconductor originates in its optimal energy band gap of approx. 1.5 eV, high absorption coefficient, and the high material abundance and low toxicity of all elements included. The current challenges are related to unavoidable antisite disordering stemming from the chemical similarity of the cations, which causes bulk defects and lowers the open-circuit voltage detrimentally. This, however, did not restrict the “cousin”-material, CuInGaSe2 (CIGS), which is currently one of the main thin-film photovoltaic (PV) technologies on the market. In this work, CZTS thin films have been fabricated by solution-processing, which allows relatively fast and inexpensive deposition when compared to vacuum-processed films. The nanoparticles are synthesized by the hot-injection method by mixing targeted ratios of metal salts with sulfur in diethylene glycol, resulting in a phase-pure CZTS material [1]. Inks are formulated by dispersing the particles in ethanol and water using a suitable dispersing agent. The solvents used allow that alkali metal chloride salts can also be dissolved in controllable amounts, which we have found enhances grain growth in the films during the subsequent annealing step. A Sono-tek spray-coating system with ultrasonic atomization is used. We investigate the effect of ink concentration, and spray-coating conditions, including spray power, flow rate from syringe pump, and time between consecutive spray layers. The films are annealed in a tube furnace, and to avoid decomposing the material into secondary phases, a graphite box is used to enable an overpressure of sulfur and tin-sulfide. The annealed, spray-coated films are characterized by scanning electron microscopy (SEM), optical microscopy, and Dektak profilometry.

M3 - Conference abstract in proceedings

BT - Book of Abstracts Sustain 2017

PB - Technical University of Denmark

ER -

Engberg SLJ, Murthy S, Mariño SL, Hansen O, Kofod G, Schou J. Spray-coated Cu2ZnSnS4 thin films for large-scale photovoltaic applications. In Book of Abstracts Sustain 2017. Technical University of Denmark. 2017. E-14