106 research outputs found
Employing surfactant-assisted hydrothermal synthesis to control CuGaO2 nanoparticle formation and improved carrier selectivity of perovskite solar cells
Delafossites like CuGaO2 have appeared as promising p-type semiconductor
materials for opto-electronic applications mainly due to their high optical
transparency and electrical conductivity. However, existing synthetic efforts
usually result in particles with large diameter limiting their performance
relevant to functional electronic applications. In this article, we report a
novel surfactant-assisted hydrothermal synthesis method, which allows the
development of ultrafine (~5 nm) monodispersed p-type CuGaO2 nanoparticles
(NPs). We show that DMSO can be used as a ligand and dispersing solvent for
stabilizing the CuGaO2 NPs. The resulting dispersion is used for the
fabrication of dense, compact functional CuGaO2 electronic layer with
properties relevant to advanced optoelectronic applications. As a proof of
concept, the surfactant-assisted hydrothermal synthesized CuGaO2 is
incorporated as a hole transporting layer (HTL) in the inverted p-i-n
perovskite solar cell device architecture providing improved hole carrier
selectivity and power conversion efficiency compared to conventional PEDOT:PSS
HTL based perovskite solar cells
Room Temperature Nanoparticulate Interfacial Layers for Perovskite Solar Cells via solvothermal synthesis
We present a solvothermal synthetic route to produce monodispersed CuO
nanoparticles (NPs) in the range of 5-10 nm that can be used as hole selective
interfacial layer between indium tin oxide (ITO) and perovskite active layer
for p-i-n perovskite solar cells by a spin casting the dispersions at room
temperature. The bottom electrode interface modification provided by spherical
CuO-NPs at room temperature promotes the formation of high quality perovskite
photoactive layers with large crystal size and strong optical absorption.
Furthermore, it is shown that the nanoparticulate nature of the CuO hole
transporting interfacial layer can be used to improve light manipulation within
perovskite solar cell device structure. The corresponding p-i-n
CH3NH3PbI3-based solar cells show high Voc values of 1.09 V, which is
significantly higher compared to the Voc values obtained with conventional
PEDOT:PSS hole selective contact based perovskite solar cells
Long Thermal Stability of Inverted Perovskite Photovoltaics Incorporating Fullerene-based Diffusion Blocking Layer
In this article, the stability of p-i-n perovskite solar cells is studied
under accelerated heat lifetime conditions (60 oC ,85oC and N2 atmosphere). By
using a combination of buffer layer engineering, impedance spectroscopy and
other characterization techniques, we propose the interaction of the perovskite
active layer with the top Al metal electrode through diffusion mechanisms as
the major thermal degradation pathway for planar inverted perovskite
photovoltaics (PVs) under 85oC heat conditions. We show that by using thick
solution processed fullerene buffer layer the perovskite active layer can be
isolated from the top metal electrode and improve the lifetime performance of
the inverted perovskite photovoltaics at 85 oC. Finally, we present an
optimized solution processed inverted perovskite PV device using thick
fullerene-based diffusion blocking layer with over 1000 hours accelerated heat
lifetime performance at 60oC
Nanoparticulate Metal Oxide Top Electrode Interface Modification Improves the Thermal Stability of Inverted Perovskite Photovoltaics
Solution processed {\gamma}-Fe2O3 nanoparticles via the solvothermal
colloidal synthesis in conjunction with ligand-exchange method are used for
interface modification of the top electrode in inverted perovskite solar cells.
In comparison to more conventional top electrodes such as PC(70)BM/Al and
PC(70)BM/AZO/Al, we show that incorporation of a {\gamma}-Fe2O3 provides an
alternative solution processed top electrode (PC(70)BM/{\gamma}-Fe2O3/Al) that
not only results in comparable power conversion efficiencies but also improved
thermal stability of inverted perovskite photovoltaics. The origin of improved
stability of inverted perovskite solar cells incorporating PC(70)BM/
{\gamma}-Fe2O3/Al under accelerated heat lifetime conditions is attributed to
the acidic surface nature of {\gamma}-Fe2O3 and reduced charge trapped density
within PC(70)BM/ {\gamma}-Fe2O3/Al top electrode interfaces.Comment: 24 pages, 11 figure
Electronic structure of poly-3-hexylthiophene (P3HT) thin film
This work is supported by Russian Foundation for Basic Research (Project 14-08-31088) and Ural Federal University in framework of financial support for young scientists
Characterization of TiOx barrier layers in organic solar cells: XPS and DFT studies
This work was supported by RFBR grant 14-08-31088
Near-field interactions between metal nanoparticle surface plasmons and molecular excitons in thin-films: part I: absorption
In this and the following paper (parts I and II, respectively), we systematically study the interactions between surface plasmons of metal nanoparticles (NPs) with excitons in thin-films of organic media. In an effort to exclusively probe near-field interactions, we utilize spherical Ag NPs in a size-regime where far-field light scattering is negligibly small compared to absorption. In part I, we discuss the effect of the presence of these Ag NPs on the absorption of the embedding medium by means of experiment, numerical simulations, and analytical calculations, all shown to be in good agreement. We observe absorption enhancement in the embedding medium due to the Ag NPs with a strong dependence on the medium permittivity, the spectral position relative to the surface plasmon resonance frequency, and the thickness of the organic layer. By introducing a low index spacer layer between the NPs and the organic medium, this absorption enhancement is experimentally confirmed to be a near field effect In part II, we probe the impact of the Ag NPs on the emission of organic molecules by time-resolved and steady-state photoluminescence measurements
Inverted Perovskite Photovoltaics Using Flame Spray Pyrolysis Solution Based CuAlO2/Cu−O Hole-Selective Contact
We present the functionalization process of a conductive and transparent CuAlO2/Cu-O hole-transporting layer (HTL). The CuAlO2/Cu-O powders were developed by flame spray pyrolysis and their stabilized dispersions were treated by sonication and centrifugation methods. We show that when the supernatant part of the treated CuAlO2/Cu-O dispersions is used for the development of CuAlO2/Cu-O HTLs the corresponding inverted perovskite-based solar cells show improved functionality and power conversion efficiency of up to 16.3% with negligible hysteresis effect
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