Lead-based perovskite solar cells (PSCs) have gained considerable interest since 2009 owing to their excellent optical and electrical properties, achieving a certified efficiency of 25.5% over a 12-year period. However,...
The ultra-sensitive photodetection of different wavelengths holds promising applications in high-performance optoelectronic devices and it requires an efficient and suitable semiconductor unit. Herein, we demonstrated the designable synthesis of 3D-branched hierarchical 3C-SiC/ZnO heterostructures by a three-step process and their assembling into an ultrasensitive photodetector. Microstructure analyses using high-resolution transmission electron microscopy reveal that the hierarchical 3C-SiC/ZnO heterostructure is composed of single-crystal 3C-SiC nanowires as a central stem and numerous well-aligned single-crystalline ZnO nanorods as branch shells. Optoelectronic tests on the 3C-SiC/ZnO heterostructure photodetector verify the outstanding photo-detection performance with an ultrahigh EQE (1.69 × 10%), a superior photoresponsivity (4.8 × 10 A W), a very fast response time (a rise time of 40 ms and a decay time of 60 ms), a high photo-dark current ratio of 187.8 and an excellent photocurrent stability and reproducibility, which is significantly advantageous or comparable to those of ZnO and other inorganic semiconductor nanostructure based photodetectors. To understand the excellent photodetection of hierarchical 3C-SiC/ZnO heterostructures, a band-gap energy diagram describing the photogenerated electron transport process is plotted and the corresponding mechanism is discussed. The strategy proposed in the present work will open up more opportunities for the design and boost of ultra-sensitive photodetectors based on semiconductor heterostructures.
Tin
perovskites have received great concern in solar cell research
owing to their favorable optoelectronic performance and environmental
friendliness. However, due to their poor crystallization and easy
oxidation, the performance improvement for tin-based perovskite solar
cells (TPSCs) is rather challenging. Herein, reductive 3-hydroxytyramine
hydrochloride (DACl) with NH2·HCl and phenol groups
as co-additives with SnF2 is added into the precursor to
modulate perovskite crystallization and inhibit Sn2+ oxidation
for high-performance TPSCs. The Lewis base group of NH2 HCl in DACl could bind to perovskite lattices to modulate the crystallization
with suppressed defects in the bulk and grain boundary, whereas reductive
phenol groups effectively constrain the Sn2+ oxidation.
Moreover, the undissociated DACl decreases the supersaturated concentration
of tin perovskite solution and creates a pre-nucleation site for rapid
nucleation to further regulate crystallization. Consequently, the
DACl-derived TPSCs achieve a high power-conversion efficiency (PCE)
that reaches up to 11%. More impressively, the device remains at 84%
of the initial PCE after full-sun illumination in N2 over
600 h without being encapsulated. This DACl-based synergistic modulation
of a lead-free perovskite demonstrates a feasible approach using one
molecule with different functional groups to manipulate crystallization,
Sn2+ oxidation, and defect reparation of tin perovskite
films, providing a critical guideline for constructing high-quality
perovskites by multifunctional additives with high photovoltaic performance.
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