| dc.description.abstract |
This study evaluates the influence of Ocimum lamiifolium leaf extract (OLE) concentration on
the green synthesis of zinc oxide nano particles (ZnO NPs) and their performance as an Electron
Transport Layer (ETL) in perquisite solar cells (PSCs). Synthesized across five extract-to precursor
ratios (1:2 to 3:2), the ZnO NPs followed a parabolic size trend dictated by competitive
Ostwald ripening and steric crowding kinetics, which were modeled using atomistic Kinetic
Monte Carlo (kMC) simulations. The 2:2 ratio achieved optimal stoichiometric equilibrium,
yielding highly stable, pure nano particles with a 3.19 eV optical bandgap. This sample
demonstrated an experimental crystalline core size of 10.80 nm (XRD) and an optical
confinement size of 12.10 nm (Effective Mass Model), aligning exceptionally well with the kMC
prediction of 10.24 nm (18.16% difference). EDX confirmed high purity with a minor 2.04 wt.%
carbon signature from biomolecular capping. SCAPS-1D photovoltaic simulations proved that
using this optimized ZnO (2:2) sample as an ultra-thin 20 nm ETL minimizes interfacial
recombination and resistance, achieving a peak power conversion efficiency (PCE) of 16.03%
(Jsc = 23.93 mA/cm2, Voc = 1.11V). Increasing the ETL thickness to 90 nm systematically
degraded performance due to bulk carrier trapping. This work highlights kMC validated,
biogenic ZnO as a sustainable, efficient architecture for next-generation PSCs. |
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