Dong Hee Shin

Highly flexible, high-performance perovskite solar cells with adhesion promoted AuCl3-doped graphene electrodes

Super flexible TCO-free FAPbI3−xBrx planar type inverted perovskite solar cells with a 17.9% power conversion efficiency under 1 sun conditions were demonstrated by introducing an APTES (3-aminopropyl triethoxysilane) adhesion promoter between a PET flexible substrate and a AuCl3-doped single-layer graphene transparent electrode (TCE). Due to the formation of covalent bonds by the APTES inter-layer, the AuCl3-GR/APTES/PET substrate had excellent flexibility, whereas the AuCl3-GR/PET substrate and the ITO/PET substrate had significant degradation of the sheet resistance after a bending test due to the break-off or delamination of AuCl3-GR from the PET substrate and the cracking of ITO. Accordingly, the perovskite solar cells constructed on the AuCl3-GR/APTES/PET TCE substrate exhibited excellent bending stability and they maintained their PCE at over 90% of the initial value after 100 bending cycles at R ≥ 4 mm.

Memory effect behavior with respect to the crystal grain size in the organic-inorganic hybrid perovskite nonvolatile resistive random access memory

The crystal grain size of CH3NH3PbI3 (MAPbI3) organic-inorganic hybrid perovskite (OHP) film was controllable in the range from ~60u2009nm to ~600u2009nm by non-solvents inter-diffusion controlled crystallization process in dripping crystallization method for the formation of perovskite film. The MAPbI3 OHP non-volatile resistive random access memory with ~60u2009nm crystal grain size exhibited >0.1u2009TB/in2 storage capacity, >600 cycles endurance, >104u2009s data retention time, ~0.7u2009V set, and ~−0.61u2009V re-set bias voltage.

High-Performance Solid-State PbS Quantum Dot-Sensitized Solar Cells Prepared by Introduction of Hybrid Perovskite Interlayer

High-performance solid-state PbS quantum dot-sensitized solar cells (QD-SSCs) with stable 9.2% power conversion efficiency at 1 Sun condition are demonstrated by introduction of hybrid perovskite interlayer. The PbS QDs formed on mesoscopic TiO2 (mp-TiO2) by spin-assisted successive precipitation and anionic exchange reaction method do not exhibit PbSO4 but have PbSO3 oxidation species. By introducing perovskite interlayer in between mp-TiO2/PbS QDs and poly-3-hexylthiophene, the PbSO3 oxidation species are fully removed in the PbS QDs and thereby the efficiency of PbS QD-SSCs is enhanced over 90% compared to the pristine PbS QD-SSCs.

Super-flexible bis(trifluoromethanesulfonyl)-amide doped graphene transparent conductive electrodes for photo-stable perovskite solar cells

Super-flexible bis(trifluoromethanesulfonyl)-amide (TFSA)-doped graphene transparent conducting electrode (GR TCE)-based FAPbI3 − xBrx perovskite solar cells with 18.9% power conversion efficiency (PCE) for a rigid device and 18.3% for a flexible one are demonstrated because the TFSA-doped GR TCE reveals high conductivity and high transmittance. The unencapsulated TFSA-doped GR TCE-based cell maintained ∼95% of its initial PCE under a continuous light soaking of 1 Sun at 60 °C/30% relative humidity for 1000 h. In addition, the TFSA-doped GR TCE-based flexible perovskite solar cells show excellent bending stabilities, maintaining PCEs of ∼85, ∼75, and ∼35% of their original values after 5000 bending cycles, at R = 12, 8, and 4 mm, respectively.

High-Performance Next-Generation Perovskite Nanocrystal Scintillator for Nondestructive X-Ray Imaging

Readily commercializable and cost-effective next-generation CsPbBr3 perovskite nanocrystals (PNCs) based X-ray detectors are demonstrated. The PNCs-based X-ray detector exhibits higher spatial resolution (9.8 lp mm-1 at modulation transfer function (MTF) = 0.2 and 12.5-8.9 lp mm-1 for a linear line chart), faster response time (≈200 ns), and comparable stability (>40 Gyair s-1 of X-ray exposure) compared with the commercialized terbium-doped gadolinium oxysulfide (GOS)-based detectors (spatial resolution = 6.2 lp mm-1 at MTF = 0.2 and 6.3 lp mm-1 for a linear line chart, response time =xa0≈1200 ns) because the PNCs-based scintillator has ≈5.6-fold faster average photoluminescence lifetime and stronger emission than the GOS-based one.

Efficient Organic–Inorganic Hybrid Flexible Perovskite Solar Cells Prepared by Lamination of Polytriarylamine/CH3NH3PbI3/Anodized Ti Metal Substrate and Graphene/PDMS Transparent Electrode Substrate

Flexible Ti metal substrate-based efficient planar-type CH3NH3PbI3 (MAPbI3) organic-inorganic hybrid perovskite solar cells are fabricated by lamination of the flexible Ti metal substrate/dense TiO2 electron-transporting layer formed by anodization/MAPbI3/polytriarylamine and the graphene/polydimethylsiloxane (PDMS) transparent electrode substrate. By adjusting the anodization reaction time of the polished Ti metal substrate and the number of graphene layers in the graphene/PDMS electrode, we can demonstrate the planar-type MAPbI3 flexible solar cells with a power conversion efficiency of 15.0% (mask area = 1 cm2) under 1 sun condition.

Erratum to: Branch length similarity entropy-based descriptors for shape representation (Journal of the Korean Physical Society, (2017), 71, 10, (727-732), 10.3938/jkps.71.593)

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Structural, Optical, and Electrical Characterization of p-type Graphene for Various AuCl 3 Doping Concentrations

Single-layer graphene layers have been synthesized by using chemical vapor deposition, subsequently transferred on 300 nm and quartz substrates, and doped with by spin coating for various doping concentrations () from 1 to 10 mM. Based on the -dependent variations of Raman frequencies/peak-intensity ratios, sheet resistance, work function, and Dirac point, measured by structural, optical, and electrical analysis techniques, the p-type nature of graphene is shown to be strengthened with increasing . Especially, as estimated from the drain current-gate voltage curves of graphene field effect transistors, the hole mobility is very little varied with increasing , in strong contrast with the -dependent large variation of electron mobility. These results suggest that is one of the best p-type dopants for graphene and is promising for device applications of the doped graphene.