Inkjet-printed indium sulfide buffer layer for Cu(In,Ga)(S,Se)2 thin film solar cells

in Thin Solid Films (2022)

We report an environmentally friendly inkjet-printed indium sulfide (In2S3) buffer layer using benign chemistry and processing conditions. A pre-synthesized indium-thiourea compound is dissolved in a ... [more ▼]

We report an environmentally friendly inkjet-printed indium sulfide (In2S3) buffer layer using benign chemistry and processing conditions. A pre-synthesized indium-thiourea compound is dissolved in a mixture of water and ethanol, inkjet printed on a Cu(In,Ga)(S,Se)2 absorber and annealed in air. The buffer layer shows a β-In2S3 structure with few organic impurities and band gap in the range of 2.3 eV. An ultraviolet ozone treatment applied to the surface of the absorber prior to inkjet printing of the precursor is used to improve the wettability of the ink and therefore the surface coverage of the buffer on the absorber layer. The device with a fully covering In2S3 layer shows better open circuit voltage and fill factor than the device with a partially covering In2S3 layer. The best In2S3 device showed a light to electric power conversion efficiency similar to the reference cadmium sulfide buffer layer device. Good wettability conditions are therefore essential for higher efficiency solar cells when the buffer layer is inkjet-printed. [less ▲]

Post-deposition annealing and interfacial atomic layer deposition buffer layers of Sb2Se3/CdS stacks for reduced interface recombination and increased open-circuit voltages

in Progress in Photovoltaics (2022)

Over 15% efficient wide-band-gap Cu(In,Ga)S2 solar cell: Suppressing bulk and interface recombination through composition engineering

in Joule (2021), 5

Waste- and Cd-Free Inkjet-Printed Zn(O,S) Buffer for Cu(In,Ga)(S,Se)2 Thin-Film Solar Cells

in ACS Applied Materials and Interfaces (2021), 13

Absorber composition: A critical parameter for the effectiveness of heat treatments in chalcopyrite solar cells

in Progress in Photovoltaics (2020)

Post-device heat treatment (HT) in chalcopyrite [Cu(In,Ga)(S,Se)2] solar cells is known to improve the performance of the devices. However, this HT is only beneficial for devices made with absorbers grown ... [more ▼]

Post-device heat treatment (HT) in chalcopyrite [Cu(In,Ga)(S,Se)2] solar cells is known to improve the performance of the devices. However, this HT is only beneficial for devices made with absorbers grown under Cu-poor conditions but not under Cu excess.. We present a systematic study to understand the effects of HT on CuInSe2 and CuInS2 solar cells. The study is performed for CuInSe2 solar cells grown under Cu-rich and Cu-poor chemical potential prepared with both CdS and Zn(O,S) buffer layers. In addition, we also study Cu-rich CuInS2 solar cells prepared with the suitable Zn(O,S) buffer layer. For Cu-poor selenide device low-temperature HT leads to passivation of bulk, whereas in Cu-rich devices no such passivation was observed. The Cu-rich devices are hampered by a large shunt. The HT decreases shunt resistance in Cu-rich selenides, whereas it increases shunt resistance in Cu-rich sulfides.. The origin of these changes in device performance was investigated with capacitance-voltage measurement which shows the considerable decrease in carrier concentration with HT in Cu-poor CuInSe2, and temperature dependent current-voltage measurements show the presence of barrier for minority carriers. Together with numerical simulations, these findings support a highly-doped interfacial p+ layer device model in Cu-rich selenide absorbers and explain the discrepancy between Cu-poor and Curich device performance. Our findings provide insights into how the same treatment can have a completely different effect on the device depending on the composition of the absorber. [less ▲]

Phonon coupling and shallow defects in CuInS2

in Physical Review. B (2020), 101(8), 085119-

Ultra-thin passivation layers in cu(in,Ga)Se2 thin-film solar cells: full-area passivated front contacts and their impact on bulk doping

in Scientific Reports (2020)

Photoluminescence-Based Method for Imaging Buffer Layer Thickness in CIGS Solar Cells

in IEEE Journal of Photovoltaics (2020)

Surface characterization of epitaxial Cu-rich CuInSe2 absorbers

in IEEE Photovoltaic Specialists Conference. Conference Record (2019, July)

We investigated the electrical properties of epitaxial Cu-rich CuInSe 2 by Kelvin probe force microscopy (KPFM) under ambient and ultra-high vacuum conditions. We first measured the sample under ambient ... [more ▼]

We investigated the electrical properties of epitaxial Cu-rich CuInSe 2 by Kelvin probe force microscopy (KPFM) under ambient and ultra-high vacuum conditions. We first measured the sample under ambient conditions before and after potassium cyanide (KCN) etching. In both cases, we do not see any substantial contrast in the surface potential data; furthermore, after the KCN etching we observed outgrowths with a height around 2nm over the sample surface. On the other hand, the KPFM measurements under ultra-high vacuum conditions show a work function dependence according to the surface orientation of the Cu-rich CuInSe 2 crystal. Our results show the possibility to increase the efficiency of epitaxial Cu-rich CuInSe 2 by growing the materials in the appropriated surface orientation where the variations in work function are reduced. [less ▲]

Challenge in Cu-rich CuInSe2 thin film solar cells: Defect caused by etching

in Physical Review Materials (2019), 3