Solution-processed all-oxide solar cell based on electrodeposited Cu2O and ZnMgO by spray pyrolysis

Abstract

The paper reports on all-solution-processed, all-oxide solar cells, based on an electrodeposited Cu 2 O absorber. The transparent indium-doped zinc oxide (IZO) contact and buffer layers of zinc oxide or zinc magnesium oxide (Zn 1-x Mg x O) were fabricated by ultrasonic spray pyrolysis. The cells were completed with graphite paste top contacts. The focus was set on using exclusively environment-friendly and low-cost raw materials, deposited from aqueous solutions without organic solvents. The latter is especially important for spray pyrolysis, where high process temperatures restrict the use of flammable solvents. The developed spray pyrolysis recipes yielded conductive (25 X/sq.) and transparent IZO and various compositions of transparent Zn 1-x Mg x O layers, with a linear dependence of the energy band gap (3.28-3.50 eV) as a function of the Mg content (0-16 mol %), as seen for layers deposited by vacuum-based techniques. Solar cells with a Zn 0.88 Mg 0.12 O buffer showed an improved photovoltaic performance compared to cells with ZnO buffer or without buffer, reaching a power conversion efficiency of 0.67% with a short-circuit current density of 3.76 mA/cm 2 , an open-circuit voltage of 0.34 V and a fill factor of 52.7%. The study correlated the improved cell performance with structural and electronic properties of the heterojunction.

Rapid Processing of In-Doped ZnO by Spray Pyrolysis from Environment-Friendly Precursor Solutions

“…Borosilicate glass substrates (Schott Nexterion®D, Mainz, Germany. 7.5 × 2.5 cm 2 ) were prepared as previously reported [13]. In summary, they were ultrasonically cleaned in a Hellmanex®III (Munich, Germany) washing solution, rinsed with deionized water (DI, 18 MΩ·cm −1 ) and isopropanol, and dried in nitrogen stream.…”

Nanocrystalline Ga2O3 films deposited by spray pyrolysis from water-based solutions on glass and TCO substrates

“…Indium zinc oxide (IZO) substrates were prepared by spray pyrolysis on borosilicate substrates following a previously reported recipe. 28 In brief, a precursor solution containing 0.2 M zinc acetate dihydrate (ZnAc 2 Á2H 2 O, Sigma-Aldrich 96459), 4 mol% indium acetate (InAc 3 , Sigma-Aldrich 510270) and 8 vol% acetic acid (HAc, Sigma-Aldrich A6283) was used. Flow rate and temperature were set to 1.6 ml min À1 and 360 1C.…”

Influence of the aqueous solution composition on the morphology of Zn1−xMgxO films deposited by spray pyrolysis

“…Commercial fluorine-doped tin oxide (FTO, 2.2 mm thick, 7 O Sq À1 , Sigma-Aldrich 735140-5EA) and indium tin oxide glass substrates (ITO, 1 mm thick, Sigma-Aldrich 703192, 8-12 O Sq À1 ) were rinsed with deionized water, rinsed with isopropanol and dried in an air stream. For the preparation of 1.8 mm-thick indium-doped ZnO (IZO) films on borosilicate glass substrates the same recipe as previously reported by our group 47 was used.…”

“…An example is given by the application of a compact Zn 0.88 Mg 0.12 O film as a buffer layer in all-solution processed Cu 2 O-type all-oxide solar cells. 47…”