In this article, we present a new paradigm for organometallic hybrid perovskite solar cell using NiO inorganic metal oxide nanocrystalline as p-type electrode material and realized the first mesoscopic NiO/perovskite/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM) heterojunction photovoltaic device. The photo-induced transient absorption spectroscopy results verified that the architecture is an effective p-type sensitized junction, which is the first inorganic p-type, metal oxide contact material for perovskite-based solar cell. Power conversion efficiency of 9.51% was achieved under AM 1.5 G illumination, which significantly surpassed the reported conventional p-type dye-sensitized solar cells. The replacement of the organic hole transport materials by a p-type metal oxide has the advantages to provide robust device architecture for further development of all-inorganic perovskite-based thin-film solar cells and tandem photovoltaics.

We introduce the use of low temperature sputtered NiOx thin film, which substitutes the PEDOT-PSS and solution-processed NiOx as an effective electron blocking layer for mesoscopic NiO/CH3NH3PbI3 perovskite solar cells. The influences of film thickness and oxygen doping on the photovoltaic performances are scrutinized. The cell efficiency has been improved from 9.51 to 10.7% for devices using NiOx fabricated under pure argon atmosphere. With adequate doping under 10% oxygen flow ratio, we achieved power conversion efficiency of 11.6%. The procedure is large area scalable and has the advantage for cost-effective perovskite-based photovoltaics.

Architectures of perovskite solar cells based on inorganic p-type semiconductor.

There is a mounting effort to use nickel oxide (NiO) as p-type selective electrode for organometal halide perovskite-based solar cells. Recently, an overall power conversion efficiency using this hole acceptor has reached 18%. However, ultrafast spectroscopic investigations on the mechanism of charge injection as well as recombination dynamics have yet to be studied and understood. Using time-resolved terahertz spectroscopy, we show that hole transfer is complete on the subpicosecond time scale, driven by the favorable band alignment between the valence bands of perovskite and NiO nanoparticles (NiO(np)). Recombination time between holes injected into NiO(np) and mobile electrons in the perovskite material is shown to be hundreds of picoseconds to a few nanoseconds. Because of the low conductivity of NiO(np), holes are pinned at the interface, and it is electrons that determine the recombination rate. This recombination competes with charge collection and therefore must be minimized. Doping NiO to promote higher mobility of holes is desirable in order to prevent back recombination.

CD4(+) T cells were activated during the onset of OA, but cartilage damage was more prominent at a later stage. CD4(+) T cells were involved in the pathogenesis of OA: they induced MIP-1γ expression and subsequent osteoclast formation.

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The excitonic relaxation dynamics of perovskite adsorbed on mesoporous thin films of Al2O3 and NiO upon excitation at 450 nm were investigated with femtosecond optical gating of photoluminescence (PL) via up-conversion. The temporal profiles of emission observed in spectral region 670-810 nm were described satisfactorily with a composite consecutive kinetic model and three transient components representing one hot and two cold excitonic relaxations. All observed relaxation dynamics depend on the emission wavelength, showing a systematic time-amplitude correlation for all three components. When the NiO film was employed, we observed an extent of relaxation proceeding through the non-emissive surface state larger than through the direct electronic relaxation channel, which quenches the PL intensity more effectively than on the Al2O3 film. We conclude that perovskite is an effective hole carrier in a p-type electrode for NiO-based perovskite solar cells showing great performance.

New zinc porphyrins Y2 and Y2A2 have been utilized in perovskite solar cells specifically as hole-transporting materials (HTMs) rather than photosensitizers. The combination of MAPbI3 as photosensitizer and porphyrins as HTMs is a potential alternative to well-known MAPbI3/Spiro-OMeTAD hybrids owing to high performance and versatility toward molecular engineering of porphyrin families. A high efficiency of 16.60% is achieved by n-butyl tethered Y2 HTM (V OC = 0.99 V; J SC = 22.82 mA cm–2) which is comparable to that of Spiro-OMeTAD of 18.03% (V OC = 1.06 V; J SC = 22.79 mA cm–2). Both materials possess similar highest occupied molecular orbital level and the same order of magnitude of hole mobility at 10–4 cm2 V–1 s–1. The slightly poorer performance of 10.55% (V OC = 1.01 V; J SC = 17.80 mA cm–2) is obtained for n-dodecyl tethered Y2A2 HTM. This is believed to stem from more surface pinholes when deposited on perovskite leading to an order of magnitude slower mobility.