Self-assembled interlayer aiming at the stability of NiOx based perovskite solar cells

Inorganic NiO_(x) based inverted structure perovskite solar cells (PSCs) is reported to be more stable than that with the organic hole transport materials.In this work,NiO_(x)/MAPbI_(3) interface chemical reaction induced instability of perovskite is unveiled:Ni^(3+) and I^(-) exhibit redox reactions and deprotonation of MA^(+) happens,which result in interface defects and perovskite lattice deformation.Thus the defective interface accelerates the degradation of perovskite by defect pathways from the bottom interface to the perovskite surface contacting H_(2)O/O_(2).Self-assembled interlayer of NH_(2)^(-)end silane on NiO_(x)separates the reactive NiO_(x)and MAPbI_(3),tunes the interface energy states by–NH_(2) end group.As a result,the PSC based on the silane treated NiO_(x)achieves enhanced PCE of 20.1%with decent stability under environmental and extreme conditions (high temperature,high humidity,light infiltration).Our work highlights the interface chemical problem induced PSC instability and a simple interface modification to achieve the stable PSCs.

High-performance solar-blind ultraviolet photodetector based on electrospun TiO2-ZnTiO3 heterojunction nano- wires

High-performance solar-blind UV （ultraviolet） photodetectors （PDs） based on low-dimension semiconducting nanostructures with high sensitivity, excellent cycle stability, and the ability to operate in harsh environments are critical for solar observations, space communication, UV astronomy, and missile tracking. In this study, TiO2-ZnTiO3 heterojunction nanowire-based PDs are successfully developed and used to detect solar-blind UV light. A photoconductive analysis indicates that the fabricated PDs are sensitive to UV illumination, with high sensitivity, good stability, and high reproducibility. Further analysis indicates that the rich existence of grain boundaries within the TiO2-ZnTiO3 nanowire can greatly decrease the dark current and recombination of the electron-hole pairs and thereby significantly increase the device＇s photosensitivity, spectra responsivity （1.1 ～ 106）, and external quantum efficiency （4.3 ～ 108 %）. Moreover, the PDs exhibit good photodetective performance with fast photoresponse and recovery and excellent thermal stability at temperatures as high as 175 ℃. According to these results, TiO2-ZnTiO3 heterojunction nanowires exhibit great potential for applications in high-performance optical electronics and PDs, particularly next-generation photodetectors with the ability to operate in harsh environments.

All-inorganic dual-phase halide perovskite nanorings

In the present work,we report the growth of all-inorganic perovskite nanorings with dual compositional phases of CsPbBr_(3)and CsPb_(2)Br5 via a facile hot injection process.The self-coiling of CsPbBr_(3)-CsPb_(2)Br5 nanorings is driven by the axial stress generated on the outside surface of the as-synthesized nanobelts,which results from the lattice mismatch during the transformation of CsPbBr_(3)to CsPb_(2)Br5.The tailored growth of nanorings could be achieved by adjusting the key experimental parameters such as reaction temperature,reaction time and stirring speed during the cooling process.The photoluminescence intensity and quantum yield of nanorings are higher than those of CsPbBr_(3)nanobelts,accompanied by a narrower full width at half maximum(FWHM),suggesting their high potential for constructing self-assembled optoelectronic nanodevices.