5 research outputs found
Monolithic Perovskite-Perovskite-Organic Triple-Junction Solar Cells with a Voltage Output Exceeding 3 V
Monolithic integration of perovskite-perovskite-organic subcells yields a triple-junction solar cell with a record open-circuit voltage of 3.03 V and a power conversion efficiency of 19.4%. The proposed triple-junction architecture represents a milestone toward scalable photovoltaics, targeting efficiencies beyond the limit of single-junction devices.</p
Improved Carrier Transport in Perovskite Solar Cells Probed by Femtosecond Transient Absorption Spectroscopy
CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite thin films have been
deposited on glass/indium tin oxide/hole transport layer (HTL) substrates,
utilizing two different materials as the HTLs. In the first configuration,
the super hydrophilic polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate),
known as PEDOT:PSS, was employed as the HTL material, whereas in the
second case, the nonwetting poly(triarylamine) semiconductor polymer,
known as PTAA, was used. It was found that when PTAA is used as the
HTL material, the averaged power conversion efficiency (PCE) of the
perovskite solar cells (PSCs) remarkably increases from 12.60 to 15.67%.
To explore the mechanism behind this enhancement, the aforementioned
perovskite/HTL arrangements were investigated by time-resolved transient
absorption spectroscopy (TAS) performed under inert conditions. By
means of TAS, the charge transfer, carrier trapping, and hole injection
dynamics from the photoexcited perovskite layers to the HTL can be
directly monitored via the characteristic bleaching profile of the
perovskite at ∼750 nm. TAS studies revealed faster relaxation
times and decay dynamics when the PTAA polymer is employed, which
potentially account for the enhanced PCE observed. The TAS results
are correlated with the structure and crystalline quality of the corresponding
perovskite films, investigated by scanning electron microscopy, X-ray
diffraction, atomic force microscopy, micro-photoluminescence, and
transmittance spectroscopy. It is concluded that TAS is a benchmark
technique for the understanding of the carrier transport mechanisms
in PSCs and constitutes a figure-of-merit tool toward their efficiency
improvement