Chalcopyrite solar cells - state-of-the-art and options for improvement

in Science China: Physics, Mechanics and Astronomy (2022)

How much gallium do we need for a p-type Cu(In,Ga)Se2?

in APL Materials (2022)

Indium-free CIGS analogues: general discussion

in Faraday Discussions (2022)

Diode Factor in Solar Cells with Metastable Defects and Back Contact Recombination

in Advanced Energy Materials (2022)

Near surface defects: Cause of deficit between internal and external open-circuit voltage in solar cells

in Progress in Photovoltaics (2021)

Interface recombination in a complex multilayered thin-film solar structure causes a disparity between the internal open-circuit voltage (VOC,in), measured by photoluminescence, and the external open ... [more ▼]

Interface recombination in a complex multilayered thin-film solar structure causes a disparity between the internal open-circuit voltage (VOC,in), measured by photoluminescence, and the external open-circuit voltage (VOC,ex), that is, a VOC deficit. Aspirations to reach higher VOC,ex values require a comprehensive knowledge of the connection between VOC deficit and interface recombination. Here, a near-surface defect model is developed for copper indium di-selenide solar cells grown under Cu-excess conditions. These cell show the typical signatures of interface recombination: a strong disparity between VOC,in and VOC,ex, and extrapolation of the temperature dependent q·VOC,ex to a value below the bandgap energy. Yet, these cells do not suffer from reduced interface bandgap or from Fermi-level pinning. The model presented is based on experimental analysis of admittance and deep-level transient spectroscopy, which show the signature of an acceptor defect. Numerical simulations using the near-surface defects model show the signatures of interface recombination without the need for a reduced interface bandgap or Fermi-level pinning. These findings demonstrate that the VOC,in measurements alone can be inconclusive and might conceal the information on interface recombination pathways, establishing the need for complementary techniques like temperature dependent current–voltage measurements to identify the cause of interface recombination in the devices. [less ▲]

Understanding Performance Limitations of Cu(In,Ga)Se2 Solar Cells due to Metastable Defects—A Route toward Higher Efficiencies

in Solar RRL (2021)

How band tail recombination influences the open-circuit voltage of solar cells.

in Progress in Photovoltaics (2021)

Thin-film (Sb,Bi)2Se3 Semiconducting Layers with Tunable Band Gaps Below 1 eV for Photovoltaic Applications

in Physical Review Applied (2020), 14

Bulk and surface recombination properties in thin film semiconductors with different surface treatments from timeresolved photoluminescence measurements

in Scientific Reports (2019), 9

The knowledge of minority carrier lifetime of a semiconductor is important for the assessment of its quality and design of electronic devices. Time-resolved photoluminescence (TRPL) measurements offer the ... [more ▼]

The knowledge of minority carrier lifetime of a semiconductor is important for the assessment of its quality and design of electronic devices. Time-resolved photoluminescence (TRPL) measurements offer the possibility to extract effective lifetimes in the nanosecond range. However, it is difficult to discriminate between surface and bulk recombination and consequently the bulk properties of the semiconductor cannot be estimated reliably. Here we present an approach to constrain systematically the bulk and surface recombination parameters in semiconducting layers and reduces to finding the roots of a mathematical function. This method disentangles the bulk and surface recombination based on TRPL decay times of samples with different surface preparations. The technique is exemplarily applied to a CuInSe2 and a back-graded Cu(In,Ga)Se2 compound semiconductor, and upper and lower bounds for the recombination parameters and the mobility are obtained. Sets of calculated parameters are extracted and used as input for simulations of photoluminescence transients, yielding a good match to experimental data and validating the effectiveness of the methodology. A script for the simulation of TRPL transients is provided. [less ▲]

Alkali treatments of Cu(In,Ga)Se2 thin‐film absorbers and their impact on transport barriers

in Progress in Photovoltaics (2018)