The heme‐undecapeptide microperoxidase‐11 (MP‐11) was immobilized on mesoporous antimony‐doped tin oxide (ATO) thin‐film electrodes modified with the positively charged binding promotor polydiallyldimethylammonium chloride. Surface concentrations of MP‐11 of 1.5 nmol cm−2 were sufficiently high to enable spectroelectrochemical analyses. UV/Vis spectroscopy and resonance Raman spectroscopy revealed that immobilized MP‐11 adopts a six‐coordinated low‐spin conformation, as in solution in the presence of a polycation. Cathodic reduction of hydrogen peroxide at potentials close to +500 mV versus Ag/AgCl indicates that the reaction proceeds via a Compound I‐type like intermediate, analogous to natural peroxidases, and confirms mesoporous ATO as a suitable host material for adsorbing the heme‐peptide in its native state. A hydrogen peroxide sensor is proposed by using the bioelectrocatalytic properties of the MP‐11‐modified ATO.
The hybrid evaporation/spin-coating route has been widely
used
for fabrication of highly efficient fully textured perovskite silicon
tandem solar cells and is a promising route for upscaling. Nevertheless,
fundamental aspects of the fabrication process such as the kinetics
of perovskite crystallization and the influence of the environmental
conditions remain uncertain. In this work, we investigate the individual
stages of tandem-relevant 1.66 eV bandgap perovskite formation and
map the structural evolution from the precursor to the perovskite
phase until the degradation phase. We find that the kinetics of these
transitions can be tuned by varying the humidity or the temperature
during the annealing treatment. Specifically, increasing the relative
humidity up to 50% elevates the reaction rate and results in improved
perovskite quality. This is directly reflected in the solar cell power
conversion efficiency with a 3%abs increment on average.
While high annealing temperatures are found to promote large grain
size growth and enhanced crystallinity, we observe that above 150
°C the remnant PbI2 precursor compromises film quality.
Furthermore, the perovskite formation kinetics is fitted using the
Johnson–Mehl–Avrami–Kolmogorov model. The Avrami
constant is found in the range 0.66–0.87, indicating a diffusion-controlled
one-dimensional growth process with an associated activation energy
of 54.49 kJ/mol. Using in situ XRD, this work gives insights on key
process parameters to ensure reproducible synthesis of high-quality
perovskite films.
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