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![]() Sood, Mohit ![]() ![]() 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 ▲] Detailed reference viewed: 55 (8 UL)![]() Shukla, Sudhanshu ![]() ![]() ![]() in Joule (2021), 5 Detailed reference viewed: 130 (7 UL)![]() Shukla, Sudhanshu ![]() ![]() ![]() in Physical Review Materials (2021), 5 Detailed reference viewed: 101 (6 UL)![]() Chu, van Ben ![]() ![]() ![]() in ACS Applied Materials and Interfaces (2021), 13 Detailed reference viewed: 153 (10 UL)![]() Sood, Mohit ![]() ![]() ![]() in Solar RRL (2021) Detailed reference viewed: 44 (0 UL)![]() Sood, Mohit ![]() ![]() ![]() 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 ▲] Detailed reference viewed: 160 (9 UL)![]() Kameni Boumenou, Christian ![]() in Physical Review Materials (2020) Detailed reference viewed: 205 (23 UL)![]() Lomuscio, Alberto ![]() ![]() ![]() in Physical Review. B (2020), 101(8), 085119- Detailed reference viewed: 255 (22 UL)![]() ; Spindler, Conrad ![]() ![]() in IEEE (2020) Detailed reference viewed: 145 (22 UL)![]() Werner, Florian ![]() ![]() in Scientific Reports (2020) Detailed reference viewed: 169 (5 UL)![]() Weiss, Thomas ![]() ![]() ![]() in Physical Review Applied (2020), 14 Detailed reference viewed: 128 (10 UL)![]() Rey, Germain ![]() in IEEE Journal of Photovoltaics (2020) Detailed reference viewed: 137 (10 UL)![]() Colombara, Diego ![]() ![]() in Nature Communications (2020) Detailed reference viewed: 249 (5 UL)![]() Martin Lanzoni, Evandro ![]() ![]() ![]() 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 ▲] Detailed reference viewed: 127 (25 UL)![]() Lomuscio, Alberto ![]() ![]() in Physical Review Applied (2019), 11 Detailed reference viewed: 517 (23 UL)![]() Elanzeery, Hossam ![]() ![]() ![]() in Physical Review Materials (2019), 3 Detailed reference viewed: 189 (13 UL)![]() Lomuscio, Alberto ![]() ![]() ![]() in 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC (2018, November 29) CuInS-based solar cells suffer from a low open circuit voltage. Absorbers grown under both Cu-excess and Cudeficiency have been used to fabricate record efficiency photovoltaic cells. In this work, we ... [more ▼] CuInS-based solar cells suffer from a low open circuit voltage. Absorbers grown under both Cu-excess and Cudeficiency have been used to fabricate record efficiency photovoltaic cells. In this work, we present the influence of stoichiometry on the quality of absorbers by means of calibrated room temperature photoluminescence and quasi Fermi level splitting evaluation (qFLs). Deep defects-related photoluminescence decreases using higher Cu/In ratio, leading to a corresponding improvement in qFLs, with values above 900 meV for high copper rich absorbers. © 2018 IEEE. [less ▲] Detailed reference viewed: 183 (7 UL)![]() ; ; et al in Frontiers in Pharmacology (2018), 9 A prominent role of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels has been suggested based on their expression and (dys)function in dorsal root ganglion (DRG) neurons, being likely ... [more ▼] A prominent role of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels has been suggested based on their expression and (dys)function in dorsal root ganglion (DRG) neurons, being likely involved in peripheral nociception. Using HCN blockers as antinociceptive drugs is prevented by the widespread distribution of these channels. However, tissue-specific expression of HCN isoforms varies significantly, HCN1 and HCN2 being considered as major players in DRG excitability. We characterized the pharmacological effect of a novel compound, MEL55A, able to block selectively HCN1/HCN2 isoforms, on DRG neuron excitability in-vitro and for its antiallodynic properties in-vivo. HEK293 cells expressing HCN1, HCN2, or HCN4 isoforms were used to verify drug selectivity. The pharmacological profile of MEL55A was tested on mouse DRG neurons by patch-clamp recordings, and in-vivo in oxaliplatin-induced neuropathy by means of thermal hypersensitivity. Results were compared to the non-isoform-selective drug, ivabradine. MEL55A showed a marked preference toward HCN1 and HCN2 isoforms expressed in HEK293, with respect to HCN4. In cultured DRG, MEL55A reduced h amplitude, both in basic conditions and after stimulation by forskolin, and cell excitability, its effect being quantitatively similar to that observed with ivabradine. MEL55A was able to relieve chemotherapy-induced neuropathic pain. In conclusion, selective blockade of HCN1/HCN2 channels, over HCN4 isoform, was able to modulate electrophysiological properties of DRG neurons similarly to that reported for classical Ih blockers, ivabradine, resulting in a pain-relieving activity. The availability of small molecules with selectivity toward HCN channel isoforms involved in nociception might represent a safe and effective strategy against chronic pain. [less ▲] Detailed reference viewed: 163 (2 UL)![]() Elanzeery, Hossam ![]() ![]() ![]() in Progress in Photovoltaics (2018) Thin film tandem solar cells provide a promising approach to achieve high efficiencies. These tandem cells require at least a bottom low bandgap and an upper high bandgap solar cell. In this contribution ... [more ▼] Thin film tandem solar cells provide a promising approach to achieve high efficiencies. These tandem cells require at least a bottom low bandgap and an upper high bandgap solar cell. In this contribution, 2 high‐performance Cu(In,Ga)Se2 cells with bandgaps as low as 1.04 and 1.07 eV are presented. These cells have shown certified efficiencies of 15.7% and 16.6% respectively. Measuring these cells under a 780‐nm longpass filter, corresponding to the bandgap of a typical top cell in tandem applications (1.57 eV), they achieved efficiencies of 7.9% and 8.3%. Admittance measurements showed no recombination active deep defects. One additional high‐performance CuInSe2 thin film solar cell with bandgap of 0.95 eV and efficiency of 14.1% is presented. All 3 cells have the potential to be integrated as bottom low bandgap cells in thin film tandem applications achieving efficiencies around 24% stacked with an efficient high bandgap top cell. [less ▲] Detailed reference viewed: 253 (6 UL)![]() Babbe, Finn ![]() ![]() ![]() in Physical Review Materials (2018), 2(10), 105405 Detailed reference viewed: 167 (6 UL) |
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