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In this work, an efficient and stable inverted planar perovskite solar cell (PSC) with water additive has been prepared in ambient air. Adding moderate water additive to CH 3 NH 3 PbI 3−x Cl x precursor solution leads to growth in quality of CH 3 NH 3 PbI 3−x Cl x film, because the boiling point of water is lower than that of N, N-dimethylformamide. The annealing temperature of the CH 3 NH 3 PbI 3−x Cl x film is controlled to 105 °C (slightly higher than the boiling point of water) to obtain the dense perovskite film rapidly in ambient environment with ~ 40% relative humidity. The highest power conversion efficiency (PCE) of PSC with water additive is 14.02%, higher than that (11.17%) of the reference device without water additive. In addition, the aqueous CH 3 NH 3 PbI 3−x Cl x solution is transformed into the stable perovskite film through the method of rapid annealing. The stable CH 3 NH 3 PbI 3−x Cl x ·nH 2 O system can resist the decomposition of perovskite film and weaken iodide ion migration in PSCs, which enhance stability of the device under the atmospheric environment. After being stored in the air for 120 h, the PSC device with water additive still has an PCE of 12.01%, higher than that (1.64%) of the reference device. [ABSTRACT FROM AUTHOR]

Abstract: Solution-processable functionalized graphene (SPFGraphene) and functionalized multiwalled carbon nanotubes(f-MWCNTs) are introduced for heterojunction solar cell. The performance of the device has improved by the incorporation of both SPFGraphene and f-MWCNTs. The open-circuit voltage (V oc), short-circuit current density (J sc), fill factor (FF) and power conversion efficiency (η) were 0.67V, 4.7mA/cm2, 32%, and 1.05%, respectively. Here, we expect that SPFGraphene acts as exciton dissociation and provide percolation paths for electron transfer, whereas f-MWCNTs provide efficient hole transportation. SPFGraphene and f-MWCNTs incorporation yields better carrier mobility, easy exciton splitting, and suppression of charge recombination, thereby improving photovoltaic action. [ABSTRACT FROM AUTHOR]

Abstract: Herein we report a study of the doping of the poly(2-methoxy-5-(30,70-dimethyloctyloxy)-1,4- phenylenevinylene) (MDMO-PPV), poly (3-oc tylthiophene) (P3OT), to the organic photovoltaic devices based on poly (3-hexylthiophene) (P3HT) and graphene derivative bulk heterojunction structure (BHJ). The addition of the donor polymers to P3HT:Graphene BJT solar cells resulted in a more broad absorption range. The interrelationships between UV–vis absorption, fill factor (FF), energy conversion efficiency (ECE) and current density have been simulated. Dependency of the open-circuit voltage (Voc) was based on different doped donors, which is due to the band structure of BHJ where the energy level difference between the highest occupied molecular orbital (HOMO) of the co-donors and the lowest occupied molecular orbital (LUMO) of the solution-processable functionalized graphene oxide (SPFGO) as acceptor was increased. The investigation indicated that the ECE of the co-donors:SPFGO BHJ solar devices with moderate doped donor amount can be influenced by the change of molecular packing structure, which can be interpreted in terms of incorporating doped donor. The XRD investigation of the complex donors/graphene BHJ solar device showed a well-organized intraplane structure with lamellae oriented normal to the substrate. In addition, The SEM investigation indicated the surface roughness morphology of the hybrid active layer film. [Copyright &y& Elsevier]