3 research outputs found
Thermally Stable Silver Nanowires-Embedding Metal Oxide for Schottky Junction Solar Cells
Thermally
stable silver nanowires (AgNWs)-embedding metal oxide
was applied for Schottky junction solar cells without an intentional
doping process in Si. A large scale (100 mm<sup>2</sup>) Schottky
solar cell showed a power conversion efficiency of 6.1% under standard
illumination, and 8.3% under diffused illumination conditions which
is the highest efficiency for AgNWs-involved Schottky junction Si
solar cells. Indium–tin–oxide (ITO)-capped AgNWs showed
excellent thermal stability with no deformation at 500 °C. The
top ITO layer grew in a cylindrical shape along the AgNWs, forming
a teardrop shape. The design of ITO/AgNWs/ITO layers is optically
beneficial because the AgNWs generate plasmonic photons, due to the
AgNWs. Electrical investigations were performed by Mott–Schottky
and impedance spectroscopy to reveal the formation of a single space
charge region at the interface between Si and AgNWs-embedding ITO
layer. We propose a route to design the thermally stable AgNWs for
photoelectric device applications with investigation of the optical
and electrical aspects
Enhanced Photocurrents with ZnS Passivated Cu(In,Ga)(Se,S)<sub>2</sub> Photocathodes Synthesized Using a Nonvacuum Process for Solar Water Splitting
Chalcopyrite
CuÂ(In,Ga)Â(Se,S)<sub>2</sub> (CIGS) semiconductors
are potential candidates for use in photoelectrochemical (PEC) hydrogen
generation due to their excellent optical absorption properties and
high conduction band edge position. In the present research, CIGS
thin film was successfully prepared on a transparent substrate (F:SnO<sub>2</sub> glass) using a solution-based process and applied for a photocathode
in solar water splitting, which shows control of the surface state
associated with sulfurization/selenization process significantly influences
on the PEC activity. A ZnS passivation surface layer was introduced,
which effectively suppresses charge recombination by surface states
of CIGS. The CIGS/ZnS/Pt photocathode exhibited highly enhanced PEC
activity (∼24 mA·cm<sup>–2</sup> at −0.3
V vs RHE). The performances of our CIGS photocathode on the transparent
substrate were also characterized under front/back light illumination,
and the incident photon to current conversion efficiency (IPCE) drastically
changed depending on the illumination directions showing decreased
IPCE especially under UV region with back illumination. The slow minority
carrier (electron) transportation is suggested as a limiting factor
for the PEC activity of the CIGS photocathode
Colloidal Wurtzite Cu<sub>2</sub>SnS<sub>3</sub> (CTS) Nanocrystals and Their Applications in Solar Cells
In
the development of low-cost, efficient, and environmentally
friendly thin-film solar cells (TFSCs), the search continues for a
suitable inorganic colloidal nanocrystal (NC) ink that can be easily
used in scalable coating/printing processes. In this work, we first
report on the colloidal synthesis of pure wurtzite (WZ) Cu<sub>2</sub>SnS<sub>3</sub> (CTS) NCs using a polyol-mediated hot injection route,
which is a nontoxic synthesis method. The synthesized material exhibits
a random distribution of CTS nanoflakes with an average lateral dimension
of ∼94 ± 15 nm. We also demonstrate that CTS NC ink can
be used to fabricate low-cost and environmentally friendly TFSCs through
an ethanol-based ink process. The annealing of as-deposited CTS films
was performed under different S vapor pressures in a graphite box
(volume; 12.3 cm<sup>3</sup>), at 580 °C for 10 min using a rapid
thermal annealing (RTA) process. A comparative study on the performances
of the solar cells with CTS absorber layers annealed under different
S vapor pressures was conducted. The device derived from the CTS absorber
annealed at 350 Torr of S vapor pressure showed the best conversion
efficiency 2.77%, which is the first notable efficiency for an CTS
NCs ink-based TFSC. In addition, CTS TFSC’s performance degraded
only slightly after 50 days in air atmosphere and under damp heating
at 90 °C for 50 h, indicating their good stability. These results
confirm that WZ CTS NCs may be very attractive and interesting light-absorbing
materials for fabricating efficient solar-harvesting devices