Among the n-type metal oxide materials used in the planar perovskite solar cells, zinc oxide (ZnO) is a promising candidate to replace titanium dioxide (TiO 2 ) due to its relatively high electron mobility, high transparency, and versatile nanostructures. Here, we present the application of low temperature solution processed ZnO/Al-doped ZnO (AZO) bilayer thin film as electron transport layers (ETLs) in the inverted perovskite solar cells, which provide a stair-case band profile. Experimental results revealed that † A Design Based on Stair-case Band Alignment of Electron Transport Layer for Improving Performance and Stability in Planar Perovskite Solar Cells 1 arXiv:1708.03153v1 [physics.app-ph] 10 Aug 2017 the power conversion efficiency (PCE) of perovskite solar cells were significantly increased from 12.25 to 16.07% by employing the AZO thin film as the buffer layer.Meanwhile, the short-circuit current density (J sc ), open-circuit voltage (V oc ), and fill factor (FF) were improved to 20.58 mA/cm 2 , 1.09V, and 71.6%, respectively. The enhancement in performance is attributed to the modified interface in ETL with staircase band alignment of ZnO/AZO/CH 3 NH 3 PbI 3 , which allows more efficient extraction of photogenerated electrons in the CH 3 NH 3 PbI 3 active layer. Thus, it is demonstrated that the ZnO/AZO bilayer ETLs would benefit the electron extraction and contribute in enhancing the performance of perovskite solar cells.

Optofluidic lasers are emerging building blocks with immense potential in the development of miniaturized light sources, integrated photonics, and sensors. The capability of on-demand lasing output with programmable and continuous wavelength tunability over a broad spectral range enables key functionalities in wavelength-division multiplexing and manipulation of light-matter interactions. However, the ability to control multicolor lasing characteristics within a small mode volume with high reconfigurability remains challenging. The color gamut is also restricted by the number of dyes and emission wavelength of existing materials. In this study, we introduce a fully programmable multicolor laser by encapsulating organic-dye-doped cholesteric liquid crystal microdroplet lasers in an optofluidic fiber. A mechanism for tuning laser emission wavelengths was proposed by manipulating the topologically induced nanoshell structures in microdroplets with different chiral dopant concentrations. Precision control of distinctive lasing wavelengths and colors covering the entire visible spectra was achieved, including monochromatic lasing, dual-color lasing, tri-color lasing, and white colored lasing with tunable color temperatures. Our findings revealed a CIE color map with 145% more perceptible colors than the standard RGB space, shedding light on the development of programmable lasers, multiplexed encoding, and biomedical detection.

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The hydrogenated amorphous silicon thin film solar cell fabricated on the glass substrate patterned by hexagonal nanocylinder array prepared by self-assembled SiO2 nanoparticles and nanosphere lithography was investigated. It is demonstrated that the short-circuit current of the patterned solar cell with 65 nm depth nanocylinder increases from 12.3 to 14.4 mA/cm2, and the efficiency increases from 5.18% to 6.59% as compared to the flat solar cell. These phenomena suggest that both effective light trapping and localized surface plasmon lead to significant improvement of light absorption in amorphous silicon solar cells.

Accuratecharacterizationandreportingoforganicphotovoltaic(OPV)deviceperformanceremainsone\ud of theimportantchallengesinthe field. Thelargespreadamongtheefficiencies ofdeviceswiththesame\ud structure reportedbydifferentgroupsissignificantly causedbydifferentproceduresandequipment\ud used duringtesting.Thepresentedarticleaddressesthisissuebyofferinganewmethodofdevice\ud testing using “suitcase sample” approach combinedwithoutdoortestingthatlimitsthediversityofthe\ud equipment,andastrictmeasurementprotocol.Aroundrobinoutdoorcharacterizationofroll-to-roll\ud coated OPVcellsandmodulesconductedamong46laboratoriesworldwideispresented,wherethe\ud samples andthetestingequipmentwereintegratedinacompactsuitcasethatservedbothasasample\ud transportation toolandasaholderandtestequipmentduringtesting.Inaddition,aninternetbased\ud coordination wasusedviaplasticphotovoltaics.orgthatallowedfastandefficient communicationamong\ud participants andprovidedacontrolledreportingformatfortheresultsthateasedtheanalysisofthe\ud data. Thereporteddeviationsamongthelaboratorieswerelimitedto5%whencomparedtotheSi\ud referencedeviceintegratedinthesuitcaseandwereupto8%whencalculatedusingthelocalirradiance\ud data. Therefore,thismethodoffersafast,cheapandefficient toolforsamplesharingandtestingthat\ud allowsconductingoutdoormeasurementsofOPVdevicesinareproduciblemanner